RARE DISEASE
Shiga toxin-associated hemolytic uremic syndrome
Shiga toxin-associated hemolytic uremic syndrome
Shiga toxin-associated hemolytic uremic syndrome
Synonyms: D+ HUS, EHEC-HUS, Hemolytic uremic syndrome associated with Shiga toxin-producing Escherichia coli, Hemolytic uremic syndrome with diarrhea, STEC-HUS, Shiga-like toxin-associated HUS, Stx-HUS, Typical HUS, Typical hemolytic uremic syndrome
Synonyms: D+ HUS, EHEC-HUS, Hemolytic uremic syndrome associated with Shiga toxin-producing Escherichia coli, Hemolytic uremic syndrome with diarrhea, STEC-HUS, Shiga-like toxin-associated HUS, Stx-HUS, Typical HUS, Typical hemolytic uremic syndrome
Synonyms: D+ HUS, EHEC-HUS, Hemolytic uremic syndrome associated with Shiga toxin-producing Escherichia coli, Hemolytic uremic syndrome with diarrhea, STEC-HUS, Shiga-like toxin-associated HUS, Stx-HUS, Typical HUS, Typical hemolytic uremic syndrome
Drug discovery
6
drugs
With orphan designations
Overview
Shiga toxin-associated hemolytic uremic syndrome (STEC-HUS) is a thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, typically triggered by Shiga toxin-producing E. coli (STEC) infections. It often follows bloody diarrhea and can progress to renal failure, neurologic complications, or death. Diagnosis relies on clinical triad confirmation and STEC detection via stool PCR or serology [1][2][6][9].
Burden
Acute kidney failure occurs in 50–70% of patients; mortality ranges 2–5% in children but rises to 20% in adults with comorbidities [6][17][18].
Chronic kidney disease develops in 10–25% of survivors, necessitating lifelong monitoring [13][16].
Annual global economic burden exceeds $400 million, driven by dialysis costs and long-term renal sequelae [6][13].
Therapies
Supportive care: Isotonic fluid resuscitation, dialysis (peritoneal preferred in children), and transfusions (avoid platelets unless bleeding) [3][5][16].
Targeted therapies: Eculizumab use remains controversial; limited evidence supports plasma exchange [3][18].
Investigational: Monoclonal antibodies (e.g., Shigamabs®) and Gb3 analogs show preclinical promise [8][16].
Categories: rare hematological diseases, rare renal diseases, rare transplant-related disorders
Research Papers
624 drug discovery papers about Shiga toxin-associated hemolytic uremic syndrome, with 4 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
624 drug discovery papers about Shiga toxin-associated hemolytic uremic syndrome, with 4 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-09-26 | Gypenosides Mitigate STEC-Induced Intestinal Injury Through Modulation of Ferroptosis Involving the ATF4-CHAC1-GPX4 Axis.
Shiga toxin-producing Escherichia coli (STEC) infection causes severe enteropathies and hemolytic uremic syndrome, yet non-antibiotic therapeutic strategies remain limited. This study evaluated whether gypenosides (GPs) protect against STEC-induced intestinal injury and investigated the underlying mechanisms. Mice were pretreated with GPs prior to STEC challenge, and protective effects were comprehensively assessed through survival analysis, bacterial burden quantification, transcriptomic profiling, flow cytometry, electron microscopy, and Western blotting. GPs significantly improved survival rates, alleviated diarrheal symptoms, reduced bacterial dissemination in systemic organs, and lowered Stx2 toxin levels. Furthermore, GPs effectively restored gut microbiota dysbiosis by enriching beneficial bacterial genera. Transcriptomic analysis suggested that GP treatment was associated with suppression of ferroptosis-related signaling pathways. Ultrastructural examination demonstrated ameliorated mitochondrial vacuolization, and biochemical assays confirmed decreased Fe2+ accumulation and attenuated lipid peroxidation. Mechanistically, these changes were associated with modulation of the ATF4-CHAC1-GPX4 axis and suppression of ferroptosis, together with preservation of mitochondrial integrity. Collectively, these findings identify GPs as a promising protective candidate against STEC-induced intestinal injury and highlight the ATF4-CHAC1-GPX4 axis as a candidate pathway for further mechanistic investigation.
2026-09-11 | The antibiotic NAB815 does not induce SOS response and toxin production in Shiga toxin-producing Escherichia coli at sub-bactericidal concentrations
Hemolytic uremic syndrome (HUS) is a rare but severe clinical condition, primarily caused by Shiga toxin-producing Escherichia coli (STEC) infections. A critical early step in the pathogenesis of HUS is the entry of Shiga toxins (Stx) into the bloodstream, where they interact with circulating blood cells via globotriaosylceramide (Gb3Cer) and Toll-like receptor 4 (TLR4). This triggers the release of Stx-containing extracellular vesicles (EV), a critical late step for HUS onset. Currently, there are no specific therapeutic interventions for HUS, and the management of STEC-infected patients is largely supportive. Antibiotics are generally avoided due to the risk of inducing the bacterial SOS response thereby enhancing Stx phage activation and toxin production. Recently, our group developed NAB815, a polymyxin B derivative capable of inhibiting Stx2a binding to TLR4, thereby reducing the release of Stx-containing EV and enhancing survival in cellular and animal models. However, as NAB815 is an antibiotic, it is unclear whether it might also have an undesirable impact on Stx production via phage activation. Here, we demonstrate that exposure of reporter or wild type clinical STEC strains to NAB815 neither triggered the SOS response nor increased Stx1 or Stx2 amounts. These results indicate that NAB815 may mitigate Stx-mediated toxicity without having an off-target effect on Stx phage activation, supporting its potential as a safe therapeutic intervention for STEC patients.
2026-09-02 | PO01 | SHIGA-TOXIN-PRODUCING ESCHERICHIA COLI ISOLATED FROM FOOD IN LOMBARDY REGION: GENETIC DIVERSITY AND ANTIMICROBIAL RESISTANCE
Aim. Shiga toxin-producing Escherichia coli (STEC) can cause a wide spectrum of clinical manifestations in humans, ranging from mild diarrhea to hemolytic uremic syndrome (HUS), posing a significant threat to public health and healthcare systems worldwide. According to EFSA, STEC is the fourth leading cause of foodborne illness in the European Union, despite being underdiagnosed and underreported. Ruminants, particularly cattle, serve as the natural reservoir for these bacteria, and the ingestion of contaminated food is considered the primary transmission route to humans. This study aimed to characterize the genetic diversity and antimicrobial resistance (AMR) profiles of STEC strains isolated from food products in Lombardy region between 2018 and 2026 to provide comprehensive insights into their distribution and resistance patterns to support evidence-based control, surveillance, and prevention strategies.Methods. STEC detection was performed in accordance with the ISO/TS 13136:2012 + ISS-EU-RL VTEC Met 04 Rev 2 2021, using a real-time PCR targeting the stx1 and stx2 genes (encoding Shiga toxins 1 and 2), as well as the eae gene (encoding intimin). Positive samples underwent an additional real-time PCR to detect the serogroups most frequently associated with human infections in Europe (O111, O26, O103, O145, O157, and O104). STEC strains were isolated, and whole-genome sequencing (WGS) was performed on the Illumina MiSeq platform. Using the ARIES Galaxy Server, serogroups, virulence genes, and AMR genes were determined.Results. A total of 162 STEC strains were isolated, mainly from matrices of bovine origin (cheese – 34%, milk – 17%, and meat – 11%). Virulence gene profiling revealed that stx1 was present in 40% of the isolates, while stx2 was detected in 37%. Notably, 78% of the strains harbored the eae gene which, in association to stx genes, confers more virulence to the strains. In fact, the co-occurrence of stx2 and eae is generally correlated with severe clinical outcomes in humans. A variety of 43 different serogroups was identified among the isolates, suggesting a diversified circulation of strains within the environments of food production. In particular, 16% of the isolates belonged to 4 historically prevalent serogroups (O26 – 9%, O103 – 5%, O145 – 0.6%, O157 – 0.6%). No O111 or O104 strains were detected. Globally recognized emerging serogroups (O80, O113, and O128) were found in 16% of the isolates, underscoring the need of a continuous monitoring of the circulating serogroups, to assess their potential impact on public health. Regarding AMR, 50% of the strains exhibited resistance to at least one antimicrobial agent, and 22% were classified as multidrug-resistant (MDR, resistance to≥3 antimicrobial classes). Crucially, one MDR strain exhibited resistance to azithromycin, a bacteriostatic molecule that seems promising in preventing HUS progression in pediatric patients. The highest resistance rates were observed against β-lactams (61.4%), streptomycin and kanamycin (18.5%), and tetracycline (14.3%), emphasizing the importance of appropriate measures to control antibiotic use in livestock and of rigorous surveillance of AMR profiles in foodborne pathogens.Conclusions. The genetic diversity of STEC isolated from food products in Lombardy region emphasizes the necessity of continuous integrated surveillance through a One Health approach to support Competent Authorities in developing targeted intervention strategies aimed at mitigating foodborne risks and protecting public health.
2026-08-25 | Distribution of Shiga Toxin Genes in Shiga Toxin–Producing Escherichia coli from Healthy Livestock and Poultry in Tunisia: Zoonotic Risk and Association with Integrons
Shiga toxin–producing Escherichia coli produce Shiga toxins, the primary virulence factors responsible for severe gastroenteritis and, in some cases, hemolytic uremic syndrome. The objective of this study was to investigate host- and strain-associated factors influencing the distribution of stx genes by analyzing data from Shiga toxin–producing Escherichia coli strains isolated from fecal samples of healthy livestock and poultry in Tunisia. A total of 116 Shiga toxin–producing Escherichia coli isolates from cattle, camels, and chickens in Tunisia were analyzed for the distribution of stx genes in relation to serogroups, host species, phylogroups, and integron carriage. This analysis was carried out to identify the factors influencing stx gene frequency and to explore potential mechanisms involved in their dissemination among diverse Shiga toxin–producing Escherichia coli serotypes. Shiga toxin genes were detected in all 116 isolates, with stx1 and stx2 identified in 75% (87/116) and 32.8% (38/116) of isolates, respectively. Across the seven tested serogroups (O26, O45, O91, O103, O121, O145, and O157), stx1 was detected in all groups, whereas stx2 was most frequent in serogroup O145 and absent in O121 and O91. The prevalence of stx1 varied significantly by host (p = .002), with the highest proportion in chickens, followed by cattle, while stx2 was most prevalent in camels and secondarily in cattle (p = .001). A significantly higher prevalence of stx2 was observed in phylogroups E and Clade I compared to other phylogroups (p = .005). Furthermore, stx1 was significantly more common in integron-positive isolates than in integron-negative isolates (p = .003). Shiga toxin genes were frequently detected in high-risk serogroups (O103, O145, and O157), predominantly within pathogenic phylogroups B2 and E, indicating an increased zoonotic risk. The significant association between integrons and stx genes (p = .003) suggests the co-selection of virulence and antimicrobial resistance traits, which represents a potential public health risk in Tunisian food animals. Cite this article as: Tayh, G., & Messadi, L. (2026). Distribution of shiga toxin genes in shiga toxin–producing Escherichia coli from healthy livestock and poultry in Tunisia: zoonotic risk and association with integrons. Acta Veterinaria Eurasia, 52, 0260, doi:10.5152/actavet.2026.25260.
2026-08-12 | Protective effects of bismuth hydroxide against hemolytic uremic syndrome caused by Shiga toxin producing Escherichia coli.
Shiga toxin-producing Escherichia coli (STEC) is a major cause of foodborne disease and hemolytic uremic syndrome (HUS), a severe condition for which no specific therapies are currently available. The major virulence factor of STEC is Shiga toxin 2 (Stx2), which is encoded by the Stx2-converting bacteriophage 933 W used in this study, and phage induction plays a central role in toxin release and disease progression.In this study, we evaluated the protective in vivo effects of bismuth hydroxide gel (BHOG), a low-cost gastrointestinal compound with previously described antimicrobial and anti-toxin activities, in a murine model of STEC infection driven by the Stx2-converting bacteriophage 933 W. Mice treated with BHOG showed significantly higher survival rates compared than untreated controls (P = 0.0115), together with preservation of renal function, evidenced by significantly lower blood urea nitrogen and plasma urea levels (P < 0.05). Histological analysis demonstrated significantly reduced intestinal and renal tissues damage in treated animals compared with untreated controls. Overall, our findings provide in vivo evidence supporting a protective effect of BHOG against Shiga toxin-mediated disease. This study suggests that bismuth-based compounds may represent a potential adjunct to, or an alternative strategy for, the management of STEC-associated disease.
proteins
2026-08-26 | Inhibitory Effects of Oxysterlina 3, Satanin 1, and Curvicin Cecropins on the Growth and stx2 Gene Expression of Shiga Toxin-Producing Escherichia coli (STEC).
Shiga toxin-producing Escherichia coli (STEC) poses a significant health risk, with Stx1 and Stx2 as key virulence factors associated with hemolytic uremic syndrome (HUS). Current STEC treatment relies on supportive care, avoiding antimicrobial therapy. This study evaluates the antibacterial activity of three cecropin peptides and their effect on the expression of the stx2 gene in STEC. Employing microdilution assays and RT-qPCR, all three cecropins demonstrated antibacterial efficacy, displaying MIC and MBC values of 12.5 µg/mL, and decreased gene expression levels following treatment. Notably, these cecropins not only inhibited STEC growth but also significantly reduced stx2 mRNA expression. These findings underscore the therapeutic potential of cecropins as an alternative treatment for STEC infections and suggest they may mitigate associated complications.
2026-02-07 | Shiga Toxin 1a Blunts Shiga Toxin 2a-pathogenic Effects in Blood.
Once released into human blood, Shiga toxins (Stx) interact with platelets and leukocytes, stimulating them to form aggregates and to release pathogenic extracellular vesicles (EV) containing Stx. These EV are considered the trigger driving the transition from bloody diarrhea to the life-threatening hemolytic uremic syndrome (HUS) during human infections by Stx-producing Escherichia coli (STEC). In children, HUS is characterized by hemolytic anemia, thrombocytopenia, and acute renal failure. The risk of any STEC-infected patient of developing HUS varies significantly depending on the Stx type produced by the bacteria, i.e., it is negligible for Shiga toxin 1 (Stx1), relevant for Shiga toxin 2 (Stx2), and considerably reduced when both toxins are present.To mimic what happens in the bloodstream of patients, human blood was challenged with Stx2a, Stx1a, or both toxins, and the formation of leukocyte/platelet aggregates was evaluated by direct-flow cytometric analysis. Pathogenic blood cell-derived EV were then isolated, their number and size determined by nanoparticle tracking analysis, and their proteins characterized by capillary Western blotting.We found that the presence of Stx1a during Stx2a challenge significantly reduced the formation of pathogenic EV, particularly the large (>300 nm) EV population causing HUS development. Notably, the amount of Stx2a significantly decreased in Stx1a + Stx2a-triggered EV with respect to Stx2a-induced EV.Our findings suggest that in STEC-infected children the presence of Stx1 in association with Stx2 reduces the risk of developing HUS by lowering the release of Stx2-containing blood cell-derived EV which are considered the main culprits for HUS onset.
2024-09-27 | The Role of the N-Terminal Domain of Thrombomodulin and the Potential of Recombinant Human Thrombomodulin as a Therapeutic Intervention for Shiga Toxin-Induced Hemolytic-Uremic Syndrome.
Hemolytic-uremic syndrome (HUS) is a rare complication of an infection with Shiga toxin (Stx)-producing Escherichia coli (STEC-HUS), characterized by severe acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia, and specific therapy is still lacking. Thrombomodulin (TM) is a multi-domain transmembrane endothelial cell protein and its N-terminal domain has been implicated in the pathophysiology of some cases of HUS. Indeed, the administration of recombinant human TM (rhTM) may have efficacy in HUS. We used a Stx-based murine model of HUS to characterize the role of the N-terminal domain of TM. We show that mice lacking that domain (TMLed (-/-)) are more sensitive to Stx, with enhanced HUS progression seen at 4 days and increased mortality at 7 days post-HUS induction. In spite of these changes, renal function was less affected in surviving Stx-challenged TMLed (-/-) mice compared to their wild-type counterparts TMLed (+/+) at 7 days. Contrary to few clinical case reports from Japan, the administration of rhTM (0.06 mg/kg) to wild-type mice (C57BL/6J) with HUS did not protect against disease progression. This overall promising, but also contradictory body of evidence, requires further systematic preclinical and clinical investigations to clarify the role of TM in HUS as a potential therapeutic strategy.
2023-10-02 | Comparative evaluation of antimicrobial activity of human granulysin, bovine and porcine NK-lysins against Shiga toxin-producing Escherichia coli O157:H7.
Shiga toxin-producing Escherichia coli (STEC) O157:H7 (O157) is a foodborne pathogen causing human disease ranging from hemorrhagic colitis and hemolytic uremic syndrome to kidney failure, while remaining harmless to cattle, its primary reservoir. The severity of the human disease associated mainly with Shiga toxin production and a global emergence of antibiotic resistant STEC highlights the need for effective non-antibiotic, pre-harvest strategies to reduce O157 in cattle, the principal source of human infection. Towards this goal three synthetic antimicrobial peptides (AMPs): human granulysin (hGRNL), bovine NK-lysin (bNK2A), and porcine NK-lysin (pNKL), were tested in vitro against O157 isolates. As expected, circular dichroism spectroscopy findings were consistent with a predominantly α-helical conformation for all three AMPs in an environment mimicking bacterial outer surface or liposaccharides. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations of hGRNL (200 μM), bNK2A (12.5 μM against strain 86-24 and 25 μM against EDL933), and pNKL (6.25 μM) were determined using the Clinical and Laboratory Standards Institute broth microdilution method in Müeller-Hinton broth (cation-adjusted). The bNK2A and pNKL AMPs did not induce Shiga toxin expression in O157 at MIC, as there was a significant decrease or no change in toxin expression following 4- or 20 h incubation with the AMPs; bNK2A p <0.0001 (4 h) and p = 0.4831 (20 h); pNKL p <0.0001 (4 h) and p = 0.0001 (20 h). Propidium iodide uptake assay revealed faster O157 membrane damage or killing kinetics with bNK2A and pNKL compared to hGRNL. Nonetheless, transmission electron microscopy demonstrated that all three AMPs mediated damage to O157 membranes. In contrast, the three AMPs showed minimal cytotoxicity (<2%) against cattle red blood cells at tested concentrations (0.39-50 μM). Overall, our results demonstrate the potential for bNK2A and pNKL to be further developed into novel non-antibiotic agents to reduce O157 shedding in cattle.
2022-09-23 | Targeting the innate repair receptor axis via erythropoietin or pyroglutamate helix B surface peptide attenuates hemolytic-uremic syndrome in mice
Hemolytic-uremic syndrome (HUS) can occur as a systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli and is characterized by microangiopathic hemolytic anemia and acute kidney injury. Hitherto, therapy has been limited to organ-supportive strategies. Erythropoietin (EPO) stimulates erythropoiesis and is approved for the treatment of certain forms of anemia, but not for HUS-associated hemolytic anemia. EPO and its non-hematopoietic analog pyroglutamate helix B surface peptide (pHBSP) have been shown to mediate tissue protection via an innate repair receptor (IRR) that is pharmacologically distinct from the erythropoiesis-mediating receptor (EPO-R). Here, we investigated the changes in endogenous EPO levels in patients with HUS and in piglets and mice subjected to preclinical HUS models. We found that endogenous EPO was elevated in plasma of humans, piglets, and mice with HUS, regardless of species and degree of anemia, suggesting that EPO signaling plays a role in HUS pathology. Therefore, we aimed to examine the therapeutic potential of EPO and pHBSP in mice with Stx-induced HUS. Administration of EPO or pHBSP improved 7-day survival and attenuated renal oxidative stress but did not significantly reduce renal dysfunction and injury in the employed model. pHBSP, but not EPO, attenuated renal nitrosative stress and reduced tubular dedifferentiation. In conclusion, targeting the EPO-R/IRR axis reduced mortality and renal oxidative stress in murine HUS without occurrence of thromboembolic complications or other adverse side effects. We therefore suggest that repurposing EPO for the treatment of patients with hemolytic anemia in HUS should be systematically investigated in future clinical trials.
vaccines
2026-07-22 | Towards scalable production of recombinant EIT as a protective antigen against EHEC.
Cattle are the major reservoir and an important source of environmental dissemination of enterohemorrhagic E. coli (EHEC), a human pathogen responsible for outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. Preharvest vaccines are aimed to reduce bacterial carriage and consequently, the impact of this zoonosis. The chimeric antigen EIT has demonstrated to be protective against EHEC in murine models. In a recent study, we proposed a simple and cost-effective approach for a vaccine formulation for cattle, in which EIT was expressed and recovered from the periplasm of the laboratory strain E. coli BL21. As a proof-of-concept, the protective efficacy in mice as well as the induction of humoral immune responses in bovines were verified. In this work, we aimed to improve the production of the recombinant antigen EIT using E. coli fed-batch fermentations. An initial screening was conducted to select the medium that best sustained EIT expression using lactose for heterologous induction. M9 medium supplemented with yeast extract yielded the highest relative levels of EIT and was used for subsequent fermentation in a stirred-tank bioreactor. Thus, EIT concentration and volumetric productivity increased by approximately 600% compared to shake-flask cultivations, while EIT yield relative to biomass and specific productivity increased by approximately 130%. Following thermal permeabilization of cells for antigen recovery, the method yielded, overall, about 350 doses per L of fermented culture. The process was reproducible across three independent fermentations while retaining EIT antigenicity, as assessed by ELISA, and functionality, as it could induce antibodies that inhibited actin pedestal formation in in vitro infection assays. Thus, heterologous EIT expression was successfully transferred to a stirred-tank bioreactor, increasing antigen output and establishing a basis for further development of a scalable process for EHEC vaccine applications.
2025-08-28 | In Silico Design of a Multiepitope Vaccine Against Intestinal Pathogenic Escherichia coli Based on the 2011 German O104:H4 Outbreak Strain Using Reverse Vaccinology and an Immunoinformatic Approach.
While most Escherichia coli strains are harmless members of the gastrointestinal microbiota, certain pathogenic variants can cause severe intestinal and extraintestinal diseases. A notable outbreak of E. coli O104:H4, involving both enteroaggregative (EAEC) and enterohemorrhagic (EHEC) strains, occurred in Europe, resulting in symptoms ranging from bloody diarrhea to life-threatening colitis and hemolytic uremic syndrome (HUS). Since treatment options remain limited and have changed little over the past 40 years, there is an urgent need for an effective vaccine. Such a vaccine would offer major public health and economic benefits by preventing severe infections and reducing outbreak-related costs. A multiepitope vaccine approach, enabled by advances in immunoinformatics, offers a promising strategy for targeting HUS-causing E. coli (O104:H4 and O157:H7 serotypes) with minimal disruption to normal microbiota. This study aimed to design an immunogenic multiepitope vaccine (MEV) construct using bioinformatics and immunoinformatic tools. Comparative proteomic analysis identified 672 proteins unique to E. coli O104:H4, excluding proteins shared with the nonpathogenic E. coli K-12-MG1655 strain and those shorter than 100 amino acids. Subcellular localization (P-SORTb) identified 17 extracellular or outer membrane proteins. Four proteins were selected as vaccine candidates based on transmembrane domains (TMHMM), antigenicity (VaxiJen), and conservation among EHEC strains. Epitope prediction revealed ten B-cell, four cytotoxic T-cell, and three helper T-cell epitopes. Four MEVs with different adjuvants were designed and assessed for solubility, stability, and antigenicity. Structural refinement (GALAXY) and docking studies confirmed strong interaction with Toll-Like Receptor 4 (TLR4). In silico immune simulations (C-ImmSim) indicated robust humoral and cellular immune responses. In Conclusions, the proposed MEV construct demonstrated promising immunogenicity and warrants further validation in experimental models.
2025-01-01 | Raw datasets and image files supporting “Developing a simple, cost-effective proof-of-concept vaccine candidate against EHEC for cattle Item
Enterohemorrhagic Escherichia coli (EHEC) is a zoonotic pathogen responsible for severe human diseases, including hemorrhagic diarrhea and hemolytic uremic syndrome (HUS), primarily mediated by Shiga toxins (Stx). Intestinal colonization depends on the type III secretion system (T3SS), which induces attaching and effacing (A/E) lesions. Cattle are the main reservoir, and preharvest vaccines are key to reducing human exposure.In this work, we engineered a chimeric antigen EIT (EspA36-192-Intimin653-935-Tir258-361) to be expressed in the periplasm of E. coli BL21, enabling simple extraction by thermal shock. To favor scalable production, the process avoids the use of antibiotics, chemical inducers, and mechanical disruption, while remaining compatible with standard infrastructure and low-cost adjuvants.Immunization of mice with an EIT-enriched periplasmic fraction (EIT-PF) induced strong antibody responses with enhanced functional activity against A/E pedestal formation in vitro, and accelerated clearance of experimental E. coli O157 infection in mice. A three-dose EIT-PF immunization was tested in cattle. Notably, a single EIT-PF dose elicited antibodies that recognized multiple EHEC serotypes and EPEC, as well as each chimera component, effectively interfering with T3SS-dependent pedestal formation in vitro. Our findings support EIT-PF as a broadly reactive, proof-of-concept vaccine candidate for cattle; further studies are required to assess efficacy under field conditions.
2024-12-21 | Cryo-EM structures of engineered Shiga toxin-based immunogens capable of eliciting neutralizing antibodies with therapeutic potential against Hemolytic Uremic Syndrome
ABSTRACT Shiga toxin-producing Escherichia coli -associated hemolytic uremic syndrome (STEC-HUS) is a serious disease that causes renal failure predominantly in children. Despite its significant impact, there are currently no licensed vaccines or effective therapies available. The B subunits of Shiga toxins 1 and 2 (Stx1B and Stx2B) are suitable targets for developing neutralizing antibodies, but their pentameric assembly is unstable when isolated from the whole toxin. Taking advantage of the oligomeric symmetry shared between Stx1B and Stx2B with the lumazine synthase from Brucella spp. (BLS), we have previously engineered the chimeric toxoids BLS-Stx1B and BLS-Stx2B as immunogens to generate therapeutic equine polyclonal antibodies. The resulting product (INM004) has successfully passed phases 1 and 2 clinical trials, and a phase 3 has been launched in Argentina and seven European countries. In this work, we present the cryo-EM structures of BLS-Stx1B and BLS-Stx2B, which confirm that these engineered immunogens effectively stabilize the StxB pentamers. Moreover, our results reveal that both chimeric constructs present high flexibility at their extremes, corresponding to motions of the StxBs with respect to the BLS core. Additionally, we present structural evidence of the interaction between the chimeras and polyclonal Fab (pFab) fragments derived from INM004, demonstrating that the elicited neutralizing antibodies block most of the interaction surface of the toxins with their cellular receptors. These findings further validate this promising antibody-based therapy for mitigating STEC-HUS and demonstrate that the BLS-Stx1B and BLS-Stx2B chimeras are potential candidates for developing a human vaccine.
2024-12-11 | Development of intimin-enriched outer membrane vesicles (OMVs) as a vaccine to control intestinal carriage of Enterohemorrhagic Escherichia coli
Enterohemorrhagic Escherichia coli (EHEC) are foodborne pathogens causing severe human infections including hemorrhagic colitis and hemolytic uremic syndrome (HUS), particularly in children. Ruminants are the main reservoir of EHEC which colonize their intestinal tract through a mechanism involving the bacterial outer membrane adhesin intimin. Vaccination of cattle has shown efficacy in reducing EHEC O157:H7 shedding in feces. However, most of these vaccines are based on purified proteins and/or require the addition of adjuvants, resulting in expensive vaccines that are not used by breeders. This study introduces the development of a new type of vaccine based on Outer Membrane Vesicles (OMVs) carrying the C-terminal domain of intimin (Int280). A vaccine which combines OMVs carrying luminal Int280 and OMVs displaying surface-exposed Int280 was produced using two addressing systems based on PelB peptide signal and Lpp-OmpA hybrid protein, respectively. This mixed vaccine was tested in a mouse model as a proof of concept using the murine host-specific intestinal pathogen Citrobacter rodentium which shares a similar intimin-based adhesion mechanism with EHEC. Vaccination of mice with OMV-Int280 elicited a strong anti-intimin IgG response. Interestingly, we observed a shortened C. rodentium fecal shedding duration in immunized mice compared to the control group. This OMVs-intimin vaccine therefore represents a promising candidate for the control of EHEC intestinal carriage and fecal shedding in ruminants. IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) are foodborne pathogenic bacteria causing intestinal infection that may lead to hemorrhagic colitis and hemolytic uremic syndrome (HUS) particularly in young children. There is no effective treatment, and antibiotics are contraindicated because they promote the development of HUS. Vaccination of ruminants, the main reservoir of EHEC, has been proposed as an important strategy to reduce the fecal shedding of EHEC to reduce transmission to humans. Outer Membrane Vesicles (OMVs) derived from E. coli are a highly attractive vaccine platform. Here, we produced OMVs enriched with the C-terminal part of the intimin (Int280). As a proof of concept, we used a mice model of Citrobacter rodentium colonization as a surrogate for EHEC intestinal colonization. Vaccination elicited antibodies against intimin and decreased the duration of fecal shedding of C. rodentium . Therefore, this OMV-Int280 vaccine is a promising candidate to control EHEC intestinal carriage and fecal shedding in ruminants.
antibodies
2026-09-26 | TLR4: A Potential Therapeutic Target in the Experimental Pathogenesis of Hemolytic-Uremic Syndrome.
Childhood infections by Shiga toxin (Stx)-producing Escherichia coli (STEC) cause bloody diarrhea and the life-threatening hemolytic-uremic syndrome (HUS). Stx2, produced by STEC in the gut, is released into the bloodstream and interacts with circulating cells (monocytes, neutrophils, and platelets) through two different receptors: Gb3Cer (globotriaosylceramide) and Toll-like receptor 4 (TLR4). Consequently, blood cells form leukocyte/platelet aggregates and release pathogenic Stx2-containing extracellular vesicles (EVs) that, by damaging the kidney, induce the transition from bloody diarrhea to HUS. Human blood was incubated with Stx2 to induce the formation of neutrophil/platelet and platelet-only aggregates (observed in May-Grünwald Giemsa-stained blood smears) and pathogenic blood cell-derived EVs (isolated by size-exclusion chromatography or differential centrifugation) toxic to Vero cells (assessed by a viability assay). In the presence of a monoclonal antibody against TLR4 (anti-TLR4), the formation of neutrophil/platelet and platelet-only aggregates was greatly reduced compared to treatment with Stx2 alone. Moreover, anti-TLR4 significantly decreased the total mass of pathogenic blood cell-derived EVs produced by Stx2 (detected by nanoparticle tracking analysis), which proved less toxic to Vero cells than those produced by Stx2 alone. The impairment of the Stx2-TLR4 axis obtained during the experimental pathogenesis of HUS provides proof-of-concept evidence supporting TLR4 as a potential therapeutic target.
2026-08-05 | Favorable Outcome With Eculizumab in Hemolytic Uremic Syndrome Presenting With Severe Neurological Complications: A Case Report.
Thrombotic microangiopathies (TMAs) are a group of rare, life-threatening disorders characterized by a classic triad of MAHA, severe thrombocytopenia, and ischemic tissue injury. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are the main types of TMAs. Based on the cause, HUS can be classified as typical or atypical. We present the case of a 4-year-old child referred to King Fahad Medical City in Riyadh, Saudi Arabia, with complaints of bloody diarrhea, vomiting, and fever. The condition progressed to altered consciousness, seizures, and quadriparesis. Upon admission, the patient received plasma infusion and underwent peritoneal dialysis. Eculizumab therapy was initiated 1 week after the presentation. Hematological and renal parameters improved rapidly, but neurological recovery was gradual, with significant progress observed over 6 years of follow-up. This case highlights that severe neurological manifestations can be an initial feature of HUS, not just TTP. Eculizumab was effective and life-saving in pediatric patients with TMA and severe neurological involvement, though CNS recovery may take years.
2026-08-01 | Two-Edged Sword: A Case Report of Systemic Thrombotic Microangiopathy Induced by Anti–Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Therapy and Cured With Eculizumab Therapy in a Patient With Lung Adenocarcinoma
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as osimertinib, are standard first-line therapy for advanced non-small-cell lung cancer (NSCLC) with activating EGFR mutations. While the main renal side effects of EGFR TKIs are typically prerenal acute kidney injury (AKI) and tubular damage, glomerular diseases, especially thrombotic microangiopathy (TMA), are extremely rare. This report documents a case of systemic TMA induced by osimertinib, which responded successfully to complement-targeted therapy. A 61-year-old female with lung adenocarcinoma developed systemic TMA (manifested by AKI, microangiopathic hemolytic anemia, and thrombocytopenia) after approximately 11 months of osimertinib treatment. Renal biopsy confirmed renal TMA complicated by acute tubular injury. Following the exclusion of other common etiologies (Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome [STEC-HUS], thrombotic thrombocytopenic purpura [TTP], and major complement gene mutations linked to atypical HUS [aHUS]), the TMA was attributed to osimertinib. The patient achieved rapid and complete remission with eculizumab, a monoclonal antibody targeting complement component 5 (C5). Reinitiating low-dose osimertinib triggered TMA recurrence, which resolved after medication discontinuation. The patient was then successfully transitioned to furmonertinib (another EGFR-TKI) with eculizumab protection. After 3.5 months of treatment, eculizumab was discontinued, and the patient has since maintained stable clinical and hematological status.
2026-07-25 | Typical or atypical hemolytic uremic syndrome? That is the question.
An 11-month-old boy with a clinical diagnosis of hemolytic uremic syndrome (HUS) associated with Shiga toxin-producing Escherichia coli infection (STEC-HUS) and a documented presence of both Shiga toxin (Stx) 1 and 2 in his stool showed an unexpected drop in platelet count during recovery (day 13 after diagnosis, day 10 after platelet nadir). Although clinically mild (from 305,000/mm3 to 216,000/mm3), this decline diverged from the expected platelet course observed in a cohort of 148 confirmed STEC-HUS patients treated at our center during the last decade and described in detail elsewhere, raising suspicion of an overlapping condition. Differential diagnoses were therefore investigated. ADAMTS13 activity and homocysteine levels were within normal range, and blood tests revealed a C3 level of 0.62 g/L. Given the unusual course of platelet count, which further dropped to 157,000/mm3, alongside the decreased C3 level, atypical HUS (aHUS) was suspected and treated accordingly with intravenous eculizumab. Platelet count peaked at 417,000/mm3 within 7 days, kidney function normalized, and the patient was discharged 23 days after admission. Genetic analysis revealed two heterozygous rare variants of uncertain significance: p.(Gly759Arg) and p.(Gly110Arg) in the complement factor H (CFH) and factor I (CFI) genes, respectively. Given the diagnostic uncertainty, C5 inhibition (C5i) was discontinued, but HUS relapsed 3.5 months later following a febrile upper respiratory tract infection. This case highlights the diagnostic challenge of discriminating aHUS when STEC infection coexists. As variants in complement regulatory genes (including pathogenic, likely pathogenic, or variants of unknown significance) are not uncommon in the general population, careful monitoring of platelet count using disease-specific reference trajectories may represent a clinically useful tool to detect early deviation from classical STEC-HUS evolution and prompt timely C5i, preventing severe consequences.
2026-07-08 | [Shiga toxin-producing Escherichia coli O80 pyelonephritis complicated by hemolytic uremic syndrome in a 3-year-old girl].
Typical hemolytic uremic syndrome (HUS) in children most often follows a gastrointestinal infection caused by Shiga toxin-producing Escherichia coli (STEC). In STEC gastrointestinal infections, antibiotic therapy is generally not recommended because of the risk of increased Shiga toxin release. Extraintestinal STEC infections, including urinary tract infections, are rare and raise a therapeutic dilemma. We report the case of a 3-year-old girl with acute pyelonephritis who subsequently developed HUS despite appropriate antibiotic therapy. Urine and stool cultures identified a Shiga toxin-producing E. coli O80 strain. This case highlights that STEC may cause urinary tract infections, a rare presentation that can precede HUS, and emphasizes the complexity of therapeutic management.
other
2026-05-27 | Treatment of Shiga toxin-producing E. coli infection by CRISPR-Cas-targeted cleavage of the Shiga toxin gene in animal models.
Escherichia coli is not only a ubiquitous gut commensal but also an opportunistic pathogen responsible for severe intestinal and extraintestinal infections. Shiga toxin-producing E. coli (STEC) poses a notable public health threat, particularly in children, where infections can lead to bloody diarrhea and progress to hemolytic uremic syndrome, a life-threatening condition with long-term complications. Antibiotics are contraindicated in STEC infections because of their potential to induce prophages carrying Shiga toxin (stx) genes, triggering toxin production. Here, we developed a CRISPR-based antimicrobial strategy using a Cas12 nuclease to selectively eliminate O157 STEC clinical isolates, cleaving more than 99% of stx variants, and prevent toxin release. To enable targeted delivery, we engineered a bacteriophage-derived capsid to specifically transfer a nonreplicative DNA payload to E. coli O157, preventing its dissemination. Our therapeutic candidate, EB003, reduced bacterial burden in a murine STEC colonization model. Moreover, EB003 mitigated clinical symptoms, abrogated Stx-mediated toxicity, and accelerated epithelial repair at therapeutically relevant doses in an infant rabbit disease model. These findings demonstrate the potential of CRISPR-based antimicrobials for treating STEC infections and support further clinical development of EB003 as a precision therapeutic against antibiotic-refractory bacterial pathogens.
2025-11-07 | Spatially and Multivalent Matched Neutralizing Aptamer-Based DNA Nanostructure Alleviates Shiga Toxin Type 2 Infection.
Shiga toxin type 2 (Stx2) is a risk factor for acute bloody diarrhea and hemolytic uremic syndrome, which has posed a major threat to global public health. Currently, there is a lack of effective strategies to combat Stx2 infection. Herein, according to the structural characteristics and infection mechanism of Stx2, we have designed a structure mediated by self-assembling DNA tetrahedral nanoframes (TDN), which can orderly assemble three neutral aptamers (TDN-S) to prevent Stx2 from entering cells and inhibit Stx2 infection. The neutralizing aptamers SA, SB, and SC can respectively bind to the three sites (sites 1, 2, and 3) on the Stx2 B subunit, which coincidentally occupy the binding sites of Stx2 and Gb3 receptor. Benefiting from the simultaneous capture of three active sites, spatial matching, and the steric hindrance effect, TDN-S exhibits excellent neutralization efficiency against Stx2. The inhibition ability of Stx2 infection in vitro was evaluated by cell viability, intracellular fluorescence imaging, and ROS levels, and the inhibition rate was as high as 80.44%. The TDN-S significantly reduces the damage to the liver, kidneys, and intestines and the inflammatory response in vivo. Overall, the neutralization strategy with multimodal interaction provides a new way to alleviate the Stx2 toxicity and serves as a model for other wide-range toxin-like inhibitions.
2025-02-28 | Treatment of STEC infection via CRISPR-Cas targeted cleavage of the Shiga toxin gene in animal models
Abstract Escherichia coli is a ubiquitous gut commensal but also an opportunistic pathogen responsible for severe intestinal and extra-intestinal infections. Shiga toxin-producing E. coli (STEC) pose a significant public health threat, particularly in children, where infections can lead to bloody diarrhea and progress to hemolytic uremic syndrome (HUS), a life-threatening condition with long-term complications. Antibiotics are contraindicated in STEC infections due to their potential to induce prophages carrying Shiga toxin ( stx) genes, triggering toxin production. Here, we present a CRISPR-based antimicrobial strategy that selectively targets and eliminates O157 STEC clinical isolates while preventing toxin release. We designed a Cas12 nuclease to cleave >99% of all stx variants found in O157 strains, leading to bacterial killing and suppression of toxin production. To enable targeted delivery, we engineered a bacteriophage-derived capsid to specifically transfer a non-replicative DNA payload to E. coli O157, preventing its dissemination. In a mouse STEC colonization model, our therapeutic candidate, EB003, reduced bacterial burden by a factor of 3×10 3 . In an infant rabbit disease model, EB003 mitigated clinical symptoms, abrogated stx-mediated toxicity, and accelerated epithelial repair at therapeutically relevant doses. These findings demonstrate the potential of CRISPR-based antimicrobials for treating STEC infections and support further clinical development of EB003 as a precision therapeutic against antibiotic-refractory bacterial pathogens.
2025-01-08 | CRISPR/Cas Systems as Diagnostic and Potential Therapeutic Tools for Enterohemorrhagic Escherichia coli.
Following its discovery as an adaptive immune system in prokaryotes, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) system has been developed into a multifaceted genome editing tool. This review compiles findings aimed at implementation of this technology for selective elimination or attenuation of enterohemorrhagic Escherichia coli (EHEC). EHEC are important zoonotic foodborne pathogens that cause hemorrhagic colitis and can progress to the life-threatening hemolytic uremic syndrome (HUS). Advancements in the application of CRISPR methodology include laboratory detection and identification of EHEC, genotyping, screening for pathogenic potential, and engineering probiotics to reduce microbial shedding by cattle, the primary source of human infection. Genetically engineered phages or conjugative plasmids have been designed to target and inactivate genes whose products are critical for EHEC virulence.
2024-10-26 | Gb3 trisaccharide-bearing exosomes as a novel neutralizer for Shiga toxin type 1
Abstract Shiga toxin types 1 (Stx1) and 2 (Stx2), produced by Shiga toxin-producing Escherichia coli (STEC) and Shigella dysenteriae , are key virulence factors responsible for severe foodborne diseases, such as hemorrhagic colitis and hemolytic uremic syndrome (HUS). The receptors for Stxs are Gb3 and P1 glycotope, which contain the Galα1→4Gal epitope and are synthesized by human α1,4-galactosyltransferase (A4galt). Stx-related infections pose a global public health challenge, owing to the limited therapeutic options due to the restricted use of antibiotics. Therefore, there is an urgent need to develop novel therapeutic strategies. This study proposes an innovative strategy utilizing exosomes derived from CHO-Lec2 cells, which were modified with Functional-Spacer-Lipid (FSL) conjugates bearing the Gb3 carbohydrate epitope (exo-Gb3-FSL). Flow cytometry analysis confirmed the presence of Galα1→4Gal disaccharides on exo-Gb3-FSL constructs, enabling them to bind Stx1. Moreover, using CHO-Lec2 cells evaluated the ability of exo-Gb3-FSL agents to bind Stx1 and protect these cells from Stx1-mediated cytotoxicity. For Stx1-treated CHO-Lec2 cells, increased cell survival was observed when using 25 µM exo-Gb3-FSL constructs, compared to control cells. These findings highlight the potential of exosome-based anti-Stx1 agents as promising alternatives to conventional therapies. This innovative strategy may provide novel directions for studies on Stx1 neutralization, offering a valuable strategy for the treatment of Stx-related diseases. Highlights - Exo-Gb3-FSL constructs hold Stx1 binding Galα1→4Gal epitope. - Stx1 was effectively bound by exo-Gb3-FSL constructs. - Exo-Gb3-FSL protected CHO-Lec2 cells from Stx1. - Exo-Gb3-FSL is a promising anti-Stx1 agent.
small molecules
2026-09-26 | Gypenosides Mitigate STEC-Induced Intestinal Injury Through Modulation of Ferroptosis Involving the ATF4-CHAC1-GPX4 Axis.
Shiga toxin-producing Escherichia coli (STEC) infection causes severe enteropathies and hemolytic uremic syndrome, yet non-antibiotic therapeutic strategies remain limited. This study evaluated whether gypenosides (GPs) protect against STEC-induced intestinal injury and investigated the underlying mechanisms. Mice were pretreated with GPs prior to STEC challenge, and protective effects were comprehensively assessed through survival analysis, bacterial burden quantification, transcriptomic profiling, flow cytometry, electron microscopy, and Western blotting. GPs significantly improved survival rates, alleviated diarrheal symptoms, reduced bacterial dissemination in systemic organs, and lowered Stx2 toxin levels. Furthermore, GPs effectively restored gut microbiota dysbiosis by enriching beneficial bacterial genera. Transcriptomic analysis suggested that GP treatment was associated with suppression of ferroptosis-related signaling pathways. Ultrastructural examination demonstrated ameliorated mitochondrial vacuolization, and biochemical assays confirmed decreased Fe2+ accumulation and attenuated lipid peroxidation. Mechanistically, these changes were associated with modulation of the ATF4-CHAC1-GPX4 axis and suppression of ferroptosis, together with preservation of mitochondrial integrity. Collectively, these findings identify GPs as a promising protective candidate against STEC-induced intestinal injury and highlight the ATF4-CHAC1-GPX4 axis as a candidate pathway for further mechanistic investigation.
2026-09-11 | The antibiotic NAB815 does not induce SOS response and toxin production in Shiga toxin-producing Escherichia coli at sub-bactericidal concentrations
Hemolytic uremic syndrome (HUS) is a rare but severe clinical condition, primarily caused by Shiga toxin-producing Escherichia coli (STEC) infections. A critical early step in the pathogenesis of HUS is the entry of Shiga toxins (Stx) into the bloodstream, where they interact with circulating blood cells via globotriaosylceramide (Gb3Cer) and Toll-like receptor 4 (TLR4). This triggers the release of Stx-containing extracellular vesicles (EV), a critical late step for HUS onset. Currently, there are no specific therapeutic interventions for HUS, and the management of STEC-infected patients is largely supportive. Antibiotics are generally avoided due to the risk of inducing the bacterial SOS response thereby enhancing Stx phage activation and toxin production. Recently, our group developed NAB815, a polymyxin B derivative capable of inhibiting Stx2a binding to TLR4, thereby reducing the release of Stx-containing EV and enhancing survival in cellular and animal models. However, as NAB815 is an antibiotic, it is unclear whether it might also have an undesirable impact on Stx production via phage activation. Here, we demonstrate that exposure of reporter or wild type clinical STEC strains to NAB815 neither triggered the SOS response nor increased Stx1 or Stx2 amounts. These results indicate that NAB815 may mitigate Stx-mediated toxicity without having an off-target effect on Stx phage activation, supporting its potential as a safe therapeutic intervention for STEC patients.
2026-09-02 | PO01 | SHIGA-TOXIN-PRODUCING ESCHERICHIA COLI ISOLATED FROM FOOD IN LOMBARDY REGION: GENETIC DIVERSITY AND ANTIMICROBIAL RESISTANCE
Aim. Shiga toxin-producing Escherichia coli (STEC) can cause a wide spectrum of clinical manifestations in humans, ranging from mild diarrhea to hemolytic uremic syndrome (HUS), posing a significant threat to public health and healthcare systems worldwide. According to EFSA, STEC is the fourth leading cause of foodborne illness in the European Union, despite being underdiagnosed and underreported. Ruminants, particularly cattle, serve as the natural reservoir for these bacteria, and the ingestion of contaminated food is considered the primary transmission route to humans. This study aimed to characterize the genetic diversity and antimicrobial resistance (AMR) profiles of STEC strains isolated from food products in Lombardy region between 2018 and 2026 to provide comprehensive insights into their distribution and resistance patterns to support evidence-based control, surveillance, and prevention strategies.Methods. STEC detection was performed in accordance with the ISO/TS 13136:2012 + ISS-EU-RL VTEC Met 04 Rev 2 2021, using a real-time PCR targeting the stx1 and stx2 genes (encoding Shiga toxins 1 and 2), as well as the eae gene (encoding intimin). Positive samples underwent an additional real-time PCR to detect the serogroups most frequently associated with human infections in Europe (O111, O26, O103, O145, O157, and O104). STEC strains were isolated, and whole-genome sequencing (WGS) was performed on the Illumina MiSeq platform. Using the ARIES Galaxy Server, serogroups, virulence genes, and AMR genes were determined.Results. A total of 162 STEC strains were isolated, mainly from matrices of bovine origin (cheese – 34%, milk – 17%, and meat – 11%). Virulence gene profiling revealed that stx1 was present in 40% of the isolates, while stx2 was detected in 37%. Notably, 78% of the strains harbored the eae gene which, in association to stx genes, confers more virulence to the strains. In fact, the co-occurrence of stx2 and eae is generally correlated with severe clinical outcomes in humans. A variety of 43 different serogroups was identified among the isolates, suggesting a diversified circulation of strains within the environments of food production. In particular, 16% of the isolates belonged to 4 historically prevalent serogroups (O26 – 9%, O103 – 5%, O145 – 0.6%, O157 – 0.6%). No O111 or O104 strains were detected. Globally recognized emerging serogroups (O80, O113, and O128) were found in 16% of the isolates, underscoring the need of a continuous monitoring of the circulating serogroups, to assess their potential impact on public health. Regarding AMR, 50% of the strains exhibited resistance to at least one antimicrobial agent, and 22% were classified as multidrug-resistant (MDR, resistance to≥3 antimicrobial classes). Crucially, one MDR strain exhibited resistance to azithromycin, a bacteriostatic molecule that seems promising in preventing HUS progression in pediatric patients. The highest resistance rates were observed against β-lactams (61.4%), streptomycin and kanamycin (18.5%), and tetracycline (14.3%), emphasizing the importance of appropriate measures to control antibiotic use in livestock and of rigorous surveillance of AMR profiles in foodborne pathogens.Conclusions. The genetic diversity of STEC isolated from food products in Lombardy region emphasizes the necessity of continuous integrated surveillance through a One Health approach to support Competent Authorities in developing targeted intervention strategies aimed at mitigating foodborne risks and protecting public health.
2026-08-25 | Distribution of Shiga Toxin Genes in Shiga Toxin–Producing Escherichia coli from Healthy Livestock and Poultry in Tunisia: Zoonotic Risk and Association with Integrons
Shiga toxin–producing Escherichia coli produce Shiga toxins, the primary virulence factors responsible for severe gastroenteritis and, in some cases, hemolytic uremic syndrome. The objective of this study was to investigate host- and strain-associated factors influencing the distribution of stx genes by analyzing data from Shiga toxin–producing Escherichia coli strains isolated from fecal samples of healthy livestock and poultry in Tunisia. A total of 116 Shiga toxin–producing Escherichia coli isolates from cattle, camels, and chickens in Tunisia were analyzed for the distribution of stx genes in relation to serogroups, host species, phylogroups, and integron carriage. This analysis was carried out to identify the factors influencing stx gene frequency and to explore potential mechanisms involved in their dissemination among diverse Shiga toxin–producing Escherichia coli serotypes. Shiga toxin genes were detected in all 116 isolates, with stx1 and stx2 identified in 75% (87/116) and 32.8% (38/116) of isolates, respectively. Across the seven tested serogroups (O26, O45, O91, O103, O121, O145, and O157), stx1 was detected in all groups, whereas stx2 was most frequent in serogroup O145 and absent in O121 and O91. The prevalence of stx1 varied significantly by host (p = .002), with the highest proportion in chickens, followed by cattle, while stx2 was most prevalent in camels and secondarily in cattle (p = .001). A significantly higher prevalence of stx2 was observed in phylogroups E and Clade I compared to other phylogroups (p = .005). Furthermore, stx1 was significantly more common in integron-positive isolates than in integron-negative isolates (p = .003). Shiga toxin genes were frequently detected in high-risk serogroups (O103, O145, and O157), predominantly within pathogenic phylogroups B2 and E, indicating an increased zoonotic risk. The significant association between integrons and stx genes (p = .003) suggests the co-selection of virulence and antimicrobial resistance traits, which represents a potential public health risk in Tunisian food animals. Cite this article as: Tayh, G., & Messadi, L. (2026). Distribution of shiga toxin genes in shiga toxin–producing Escherichia coli from healthy livestock and poultry in Tunisia: zoonotic risk and association with integrons. Acta Veterinaria Eurasia, 52, 0260, doi:10.5152/actavet.2026.25260.
2026-08-12 | Protective effects of bismuth hydroxide against hemolytic uremic syndrome caused by Shiga toxin producing Escherichia coli.
Shiga toxin-producing Escherichia coli (STEC) is a major cause of foodborne disease and hemolytic uremic syndrome (HUS), a severe condition for which no specific therapies are currently available. The major virulence factor of STEC is Shiga toxin 2 (Stx2), which is encoded by the Stx2-converting bacteriophage 933 W used in this study, and phage induction plays a central role in toxin release and disease progression.In this study, we evaluated the protective in vivo effects of bismuth hydroxide gel (BHOG), a low-cost gastrointestinal compound with previously described antimicrobial and anti-toxin activities, in a murine model of STEC infection driven by the Stx2-converting bacteriophage 933 W. Mice treated with BHOG showed significantly higher survival rates compared than untreated controls (P = 0.0115), together with preservation of renal function, evidenced by significantly lower blood urea nitrogen and plasma urea levels (P < 0.05). Histological analysis demonstrated significantly reduced intestinal and renal tissues damage in treated animals compared with untreated controls. Overall, our findings provide in vivo evidence supporting a protective effect of BHOG against Shiga toxin-mediated disease. This study suggests that bismuth-based compounds may represent a potential adjunct to, or an alternative strategy for, the management of STEC-associated disease.
proteins
2026-08-26 | Inhibitory Effects of Oxysterlina 3, Satanin 1, and Curvicin Cecropins on the Growth and stx2 Gene Expression of Shiga Toxin-Producing Escherichia coli (STEC).
Shiga toxin-producing Escherichia coli (STEC) poses a significant health risk, with Stx1 and Stx2 as key virulence factors associated with hemolytic uremic syndrome (HUS). Current STEC treatment relies on supportive care, avoiding antimicrobial therapy. This study evaluates the antibacterial activity of three cecropin peptides and their effect on the expression of the stx2 gene in STEC. Employing microdilution assays and RT-qPCR, all three cecropins demonstrated antibacterial efficacy, displaying MIC and MBC values of 12.5 µg/mL, and decreased gene expression levels following treatment. Notably, these cecropins not only inhibited STEC growth but also significantly reduced stx2 mRNA expression. These findings underscore the therapeutic potential of cecropins as an alternative treatment for STEC infections and suggest they may mitigate associated complications.
2026-02-07 | Shiga Toxin 1a Blunts Shiga Toxin 2a-pathogenic Effects in Blood.
Once released into human blood, Shiga toxins (Stx) interact with platelets and leukocytes, stimulating them to form aggregates and to release pathogenic extracellular vesicles (EV) containing Stx. These EV are considered the trigger driving the transition from bloody diarrhea to the life-threatening hemolytic uremic syndrome (HUS) during human infections by Stx-producing Escherichia coli (STEC). In children, HUS is characterized by hemolytic anemia, thrombocytopenia, and acute renal failure. The risk of any STEC-infected patient of developing HUS varies significantly depending on the Stx type produced by the bacteria, i.e., it is negligible for Shiga toxin 1 (Stx1), relevant for Shiga toxin 2 (Stx2), and considerably reduced when both toxins are present.To mimic what happens in the bloodstream of patients, human blood was challenged with Stx2a, Stx1a, or both toxins, and the formation of leukocyte/platelet aggregates was evaluated by direct-flow cytometric analysis. Pathogenic blood cell-derived EV were then isolated, their number and size determined by nanoparticle tracking analysis, and their proteins characterized by capillary Western blotting.We found that the presence of Stx1a during Stx2a challenge significantly reduced the formation of pathogenic EV, particularly the large (>300 nm) EV population causing HUS development. Notably, the amount of Stx2a significantly decreased in Stx1a + Stx2a-triggered EV with respect to Stx2a-induced EV.Our findings suggest that in STEC-infected children the presence of Stx1 in association with Stx2 reduces the risk of developing HUS by lowering the release of Stx2-containing blood cell-derived EV which are considered the main culprits for HUS onset.
2024-09-27 | The Role of the N-Terminal Domain of Thrombomodulin and the Potential of Recombinant Human Thrombomodulin as a Therapeutic Intervention for Shiga Toxin-Induced Hemolytic-Uremic Syndrome.
Hemolytic-uremic syndrome (HUS) is a rare complication of an infection with Shiga toxin (Stx)-producing Escherichia coli (STEC-HUS), characterized by severe acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia, and specific therapy is still lacking. Thrombomodulin (TM) is a multi-domain transmembrane endothelial cell protein and its N-terminal domain has been implicated in the pathophysiology of some cases of HUS. Indeed, the administration of recombinant human TM (rhTM) may have efficacy in HUS. We used a Stx-based murine model of HUS to characterize the role of the N-terminal domain of TM. We show that mice lacking that domain (TMLed (-/-)) are more sensitive to Stx, with enhanced HUS progression seen at 4 days and increased mortality at 7 days post-HUS induction. In spite of these changes, renal function was less affected in surviving Stx-challenged TMLed (-/-) mice compared to their wild-type counterparts TMLed (+/+) at 7 days. Contrary to few clinical case reports from Japan, the administration of rhTM (0.06 mg/kg) to wild-type mice (C57BL/6J) with HUS did not protect against disease progression. This overall promising, but also contradictory body of evidence, requires further systematic preclinical and clinical investigations to clarify the role of TM in HUS as a potential therapeutic strategy.
2023-10-02 | Comparative evaluation of antimicrobial activity of human granulysin, bovine and porcine NK-lysins against Shiga toxin-producing Escherichia coli O157:H7.
Shiga toxin-producing Escherichia coli (STEC) O157:H7 (O157) is a foodborne pathogen causing human disease ranging from hemorrhagic colitis and hemolytic uremic syndrome to kidney failure, while remaining harmless to cattle, its primary reservoir. The severity of the human disease associated mainly with Shiga toxin production and a global emergence of antibiotic resistant STEC highlights the need for effective non-antibiotic, pre-harvest strategies to reduce O157 in cattle, the principal source of human infection. Towards this goal three synthetic antimicrobial peptides (AMPs): human granulysin (hGRNL), bovine NK-lysin (bNK2A), and porcine NK-lysin (pNKL), were tested in vitro against O157 isolates. As expected, circular dichroism spectroscopy findings were consistent with a predominantly α-helical conformation for all three AMPs in an environment mimicking bacterial outer surface or liposaccharides. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations of hGRNL (200 μM), bNK2A (12.5 μM against strain 86-24 and 25 μM against EDL933), and pNKL (6.25 μM) were determined using the Clinical and Laboratory Standards Institute broth microdilution method in Müeller-Hinton broth (cation-adjusted). The bNK2A and pNKL AMPs did not induce Shiga toxin expression in O157 at MIC, as there was a significant decrease or no change in toxin expression following 4- or 20 h incubation with the AMPs; bNK2A p <0.0001 (4 h) and p = 0.4831 (20 h); pNKL p <0.0001 (4 h) and p = 0.0001 (20 h). Propidium iodide uptake assay revealed faster O157 membrane damage or killing kinetics with bNK2A and pNKL compared to hGRNL. Nonetheless, transmission electron microscopy demonstrated that all three AMPs mediated damage to O157 membranes. In contrast, the three AMPs showed minimal cytotoxicity (<2%) against cattle red blood cells at tested concentrations (0.39-50 μM). Overall, our results demonstrate the potential for bNK2A and pNKL to be further developed into novel non-antibiotic agents to reduce O157 shedding in cattle.
2022-09-23 | Targeting the innate repair receptor axis via erythropoietin or pyroglutamate helix B surface peptide attenuates hemolytic-uremic syndrome in mice
Hemolytic-uremic syndrome (HUS) can occur as a systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli and is characterized by microangiopathic hemolytic anemia and acute kidney injury. Hitherto, therapy has been limited to organ-supportive strategies. Erythropoietin (EPO) stimulates erythropoiesis and is approved for the treatment of certain forms of anemia, but not for HUS-associated hemolytic anemia. EPO and its non-hematopoietic analog pyroglutamate helix B surface peptide (pHBSP) have been shown to mediate tissue protection via an innate repair receptor (IRR) that is pharmacologically distinct from the erythropoiesis-mediating receptor (EPO-R). Here, we investigated the changes in endogenous EPO levels in patients with HUS and in piglets and mice subjected to preclinical HUS models. We found that endogenous EPO was elevated in plasma of humans, piglets, and mice with HUS, regardless of species and degree of anemia, suggesting that EPO signaling plays a role in HUS pathology. Therefore, we aimed to examine the therapeutic potential of EPO and pHBSP in mice with Stx-induced HUS. Administration of EPO or pHBSP improved 7-day survival and attenuated renal oxidative stress but did not significantly reduce renal dysfunction and injury in the employed model. pHBSP, but not EPO, attenuated renal nitrosative stress and reduced tubular dedifferentiation. In conclusion, targeting the EPO-R/IRR axis reduced mortality and renal oxidative stress in murine HUS without occurrence of thromboembolic complications or other adverse side effects. We therefore suggest that repurposing EPO for the treatment of patients with hemolytic anemia in HUS should be systematically investigated in future clinical trials.
vaccines
2026-07-22 | Towards scalable production of recombinant EIT as a protective antigen against EHEC.
Cattle are the major reservoir and an important source of environmental dissemination of enterohemorrhagic E. coli (EHEC), a human pathogen responsible for outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. Preharvest vaccines are aimed to reduce bacterial carriage and consequently, the impact of this zoonosis. The chimeric antigen EIT has demonstrated to be protective against EHEC in murine models. In a recent study, we proposed a simple and cost-effective approach for a vaccine formulation for cattle, in which EIT was expressed and recovered from the periplasm of the laboratory strain E. coli BL21. As a proof-of-concept, the protective efficacy in mice as well as the induction of humoral immune responses in bovines were verified. In this work, we aimed to improve the production of the recombinant antigen EIT using E. coli fed-batch fermentations. An initial screening was conducted to select the medium that best sustained EIT expression using lactose for heterologous induction. M9 medium supplemented with yeast extract yielded the highest relative levels of EIT and was used for subsequent fermentation in a stirred-tank bioreactor. Thus, EIT concentration and volumetric productivity increased by approximately 600% compared to shake-flask cultivations, while EIT yield relative to biomass and specific productivity increased by approximately 130%. Following thermal permeabilization of cells for antigen recovery, the method yielded, overall, about 350 doses per L of fermented culture. The process was reproducible across three independent fermentations while retaining EIT antigenicity, as assessed by ELISA, and functionality, as it could induce antibodies that inhibited actin pedestal formation in in vitro infection assays. Thus, heterologous EIT expression was successfully transferred to a stirred-tank bioreactor, increasing antigen output and establishing a basis for further development of a scalable process for EHEC vaccine applications.
2025-08-28 | In Silico Design of a Multiepitope Vaccine Against Intestinal Pathogenic Escherichia coli Based on the 2011 German O104:H4 Outbreak Strain Using Reverse Vaccinology and an Immunoinformatic Approach.
While most Escherichia coli strains are harmless members of the gastrointestinal microbiota, certain pathogenic variants can cause severe intestinal and extraintestinal diseases. A notable outbreak of E. coli O104:H4, involving both enteroaggregative (EAEC) and enterohemorrhagic (EHEC) strains, occurred in Europe, resulting in symptoms ranging from bloody diarrhea to life-threatening colitis and hemolytic uremic syndrome (HUS). Since treatment options remain limited and have changed little over the past 40 years, there is an urgent need for an effective vaccine. Such a vaccine would offer major public health and economic benefits by preventing severe infections and reducing outbreak-related costs. A multiepitope vaccine approach, enabled by advances in immunoinformatics, offers a promising strategy for targeting HUS-causing E. coli (O104:H4 and O157:H7 serotypes) with minimal disruption to normal microbiota. This study aimed to design an immunogenic multiepitope vaccine (MEV) construct using bioinformatics and immunoinformatic tools. Comparative proteomic analysis identified 672 proteins unique to E. coli O104:H4, excluding proteins shared with the nonpathogenic E. coli K-12-MG1655 strain and those shorter than 100 amino acids. Subcellular localization (P-SORTb) identified 17 extracellular or outer membrane proteins. Four proteins were selected as vaccine candidates based on transmembrane domains (TMHMM), antigenicity (VaxiJen), and conservation among EHEC strains. Epitope prediction revealed ten B-cell, four cytotoxic T-cell, and three helper T-cell epitopes. Four MEVs with different adjuvants were designed and assessed for solubility, stability, and antigenicity. Structural refinement (GALAXY) and docking studies confirmed strong interaction with Toll-Like Receptor 4 (TLR4). In silico immune simulations (C-ImmSim) indicated robust humoral and cellular immune responses. In Conclusions, the proposed MEV construct demonstrated promising immunogenicity and warrants further validation in experimental models.
2025-01-01 | Raw datasets and image files supporting “Developing a simple, cost-effective proof-of-concept vaccine candidate against EHEC for cattle Item
Enterohemorrhagic Escherichia coli (EHEC) is a zoonotic pathogen responsible for severe human diseases, including hemorrhagic diarrhea and hemolytic uremic syndrome (HUS), primarily mediated by Shiga toxins (Stx). Intestinal colonization depends on the type III secretion system (T3SS), which induces attaching and effacing (A/E) lesions. Cattle are the main reservoir, and preharvest vaccines are key to reducing human exposure.In this work, we engineered a chimeric antigen EIT (EspA36-192-Intimin653-935-Tir258-361) to be expressed in the periplasm of E. coli BL21, enabling simple extraction by thermal shock. To favor scalable production, the process avoids the use of antibiotics, chemical inducers, and mechanical disruption, while remaining compatible with standard infrastructure and low-cost adjuvants.Immunization of mice with an EIT-enriched periplasmic fraction (EIT-PF) induced strong antibody responses with enhanced functional activity against A/E pedestal formation in vitro, and accelerated clearance of experimental E. coli O157 infection in mice. A three-dose EIT-PF immunization was tested in cattle. Notably, a single EIT-PF dose elicited antibodies that recognized multiple EHEC serotypes and EPEC, as well as each chimera component, effectively interfering with T3SS-dependent pedestal formation in vitro. Our findings support EIT-PF as a broadly reactive, proof-of-concept vaccine candidate for cattle; further studies are required to assess efficacy under field conditions.
2024-12-21 | Cryo-EM structures of engineered Shiga toxin-based immunogens capable of eliciting neutralizing antibodies with therapeutic potential against Hemolytic Uremic Syndrome
ABSTRACT Shiga toxin-producing Escherichia coli -associated hemolytic uremic syndrome (STEC-HUS) is a serious disease that causes renal failure predominantly in children. Despite its significant impact, there are currently no licensed vaccines or effective therapies available. The B subunits of Shiga toxins 1 and 2 (Stx1B and Stx2B) are suitable targets for developing neutralizing antibodies, but their pentameric assembly is unstable when isolated from the whole toxin. Taking advantage of the oligomeric symmetry shared between Stx1B and Stx2B with the lumazine synthase from Brucella spp. (BLS), we have previously engineered the chimeric toxoids BLS-Stx1B and BLS-Stx2B as immunogens to generate therapeutic equine polyclonal antibodies. The resulting product (INM004) has successfully passed phases 1 and 2 clinical trials, and a phase 3 has been launched in Argentina and seven European countries. In this work, we present the cryo-EM structures of BLS-Stx1B and BLS-Stx2B, which confirm that these engineered immunogens effectively stabilize the StxB pentamers. Moreover, our results reveal that both chimeric constructs present high flexibility at their extremes, corresponding to motions of the StxBs with respect to the BLS core. Additionally, we present structural evidence of the interaction between the chimeras and polyclonal Fab (pFab) fragments derived from INM004, demonstrating that the elicited neutralizing antibodies block most of the interaction surface of the toxins with their cellular receptors. These findings further validate this promising antibody-based therapy for mitigating STEC-HUS and demonstrate that the BLS-Stx1B and BLS-Stx2B chimeras are potential candidates for developing a human vaccine.
2024-12-11 | Development of intimin-enriched outer membrane vesicles (OMVs) as a vaccine to control intestinal carriage of Enterohemorrhagic Escherichia coli
Enterohemorrhagic Escherichia coli (EHEC) are foodborne pathogens causing severe human infections including hemorrhagic colitis and hemolytic uremic syndrome (HUS), particularly in children. Ruminants are the main reservoir of EHEC which colonize their intestinal tract through a mechanism involving the bacterial outer membrane adhesin intimin. Vaccination of cattle has shown efficacy in reducing EHEC O157:H7 shedding in feces. However, most of these vaccines are based on purified proteins and/or require the addition of adjuvants, resulting in expensive vaccines that are not used by breeders. This study introduces the development of a new type of vaccine based on Outer Membrane Vesicles (OMVs) carrying the C-terminal domain of intimin (Int280). A vaccine which combines OMVs carrying luminal Int280 and OMVs displaying surface-exposed Int280 was produced using two addressing systems based on PelB peptide signal and Lpp-OmpA hybrid protein, respectively. This mixed vaccine was tested in a mouse model as a proof of concept using the murine host-specific intestinal pathogen Citrobacter rodentium which shares a similar intimin-based adhesion mechanism with EHEC. Vaccination of mice with OMV-Int280 elicited a strong anti-intimin IgG response. Interestingly, we observed a shortened C. rodentium fecal shedding duration in immunized mice compared to the control group. This OMVs-intimin vaccine therefore represents a promising candidate for the control of EHEC intestinal carriage and fecal shedding in ruminants. IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) are foodborne pathogenic bacteria causing intestinal infection that may lead to hemorrhagic colitis and hemolytic uremic syndrome (HUS) particularly in young children. There is no effective treatment, and antibiotics are contraindicated because they promote the development of HUS. Vaccination of ruminants, the main reservoir of EHEC, has been proposed as an important strategy to reduce the fecal shedding of EHEC to reduce transmission to humans. Outer Membrane Vesicles (OMVs) derived from E. coli are a highly attractive vaccine platform. Here, we produced OMVs enriched with the C-terminal part of the intimin (Int280). As a proof of concept, we used a mice model of Citrobacter rodentium colonization as a surrogate for EHEC intestinal colonization. Vaccination elicited antibodies against intimin and decreased the duration of fecal shedding of C. rodentium . Therefore, this OMV-Int280 vaccine is a promising candidate to control EHEC intestinal carriage and fecal shedding in ruminants.
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2026-09-26 | TLR4: A Potential Therapeutic Target in the Experimental Pathogenesis of Hemolytic-Uremic Syndrome.
Childhood infections by Shiga toxin (Stx)-producing Escherichia coli (STEC) cause bloody diarrhea and the life-threatening hemolytic-uremic syndrome (HUS). Stx2, produced by STEC in the gut, is released into the bloodstream and interacts with circulating cells (monocytes, neutrophils, and platelets) through two different receptors: Gb3Cer (globotriaosylceramide) and Toll-like receptor 4 (TLR4). Consequently, blood cells form leukocyte/platelet aggregates and release pathogenic Stx2-containing extracellular vesicles (EVs) that, by damaging the kidney, induce the transition from bloody diarrhea to HUS. Human blood was incubated with Stx2 to induce the formation of neutrophil/platelet and platelet-only aggregates (observed in May-Grünwald Giemsa-stained blood smears) and pathogenic blood cell-derived EVs (isolated by size-exclusion chromatography or differential centrifugation) toxic to Vero cells (assessed by a viability assay). In the presence of a monoclonal antibody against TLR4 (anti-TLR4), the formation of neutrophil/platelet and platelet-only aggregates was greatly reduced compared to treatment with Stx2 alone. Moreover, anti-TLR4 significantly decreased the total mass of pathogenic blood cell-derived EVs produced by Stx2 (detected by nanoparticle tracking analysis), which proved less toxic to Vero cells than those produced by Stx2 alone. The impairment of the Stx2-TLR4 axis obtained during the experimental pathogenesis of HUS provides proof-of-concept evidence supporting TLR4 as a potential therapeutic target.
2026-08-05 | Favorable Outcome With Eculizumab in Hemolytic Uremic Syndrome Presenting With Severe Neurological Complications: A Case Report.
Thrombotic microangiopathies (TMAs) are a group of rare, life-threatening disorders characterized by a classic triad of MAHA, severe thrombocytopenia, and ischemic tissue injury. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are the main types of TMAs. Based on the cause, HUS can be classified as typical or atypical. We present the case of a 4-year-old child referred to King Fahad Medical City in Riyadh, Saudi Arabia, with complaints of bloody diarrhea, vomiting, and fever. The condition progressed to altered consciousness, seizures, and quadriparesis. Upon admission, the patient received plasma infusion and underwent peritoneal dialysis. Eculizumab therapy was initiated 1 week after the presentation. Hematological and renal parameters improved rapidly, but neurological recovery was gradual, with significant progress observed over 6 years of follow-up. This case highlights that severe neurological manifestations can be an initial feature of HUS, not just TTP. Eculizumab was effective and life-saving in pediatric patients with TMA and severe neurological involvement, though CNS recovery may take years.
2026-08-01 | Two-Edged Sword: A Case Report of Systemic Thrombotic Microangiopathy Induced by Anti–Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Therapy and Cured With Eculizumab Therapy in a Patient With Lung Adenocarcinoma
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as osimertinib, are standard first-line therapy for advanced non-small-cell lung cancer (NSCLC) with activating EGFR mutations. While the main renal side effects of EGFR TKIs are typically prerenal acute kidney injury (AKI) and tubular damage, glomerular diseases, especially thrombotic microangiopathy (TMA), are extremely rare. This report documents a case of systemic TMA induced by osimertinib, which responded successfully to complement-targeted therapy. A 61-year-old female with lung adenocarcinoma developed systemic TMA (manifested by AKI, microangiopathic hemolytic anemia, and thrombocytopenia) after approximately 11 months of osimertinib treatment. Renal biopsy confirmed renal TMA complicated by acute tubular injury. Following the exclusion of other common etiologies (Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome [STEC-HUS], thrombotic thrombocytopenic purpura [TTP], and major complement gene mutations linked to atypical HUS [aHUS]), the TMA was attributed to osimertinib. The patient achieved rapid and complete remission with eculizumab, a monoclonal antibody targeting complement component 5 (C5). Reinitiating low-dose osimertinib triggered TMA recurrence, which resolved after medication discontinuation. The patient was then successfully transitioned to furmonertinib (another EGFR-TKI) with eculizumab protection. After 3.5 months of treatment, eculizumab was discontinued, and the patient has since maintained stable clinical and hematological status.
2026-07-25 | Typical or atypical hemolytic uremic syndrome? That is the question.
An 11-month-old boy with a clinical diagnosis of hemolytic uremic syndrome (HUS) associated with Shiga toxin-producing Escherichia coli infection (STEC-HUS) and a documented presence of both Shiga toxin (Stx) 1 and 2 in his stool showed an unexpected drop in platelet count during recovery (day 13 after diagnosis, day 10 after platelet nadir). Although clinically mild (from 305,000/mm3 to 216,000/mm3), this decline diverged from the expected platelet course observed in a cohort of 148 confirmed STEC-HUS patients treated at our center during the last decade and described in detail elsewhere, raising suspicion of an overlapping condition. Differential diagnoses were therefore investigated. ADAMTS13 activity and homocysteine levels were within normal range, and blood tests revealed a C3 level of 0.62 g/L. Given the unusual course of platelet count, which further dropped to 157,000/mm3, alongside the decreased C3 level, atypical HUS (aHUS) was suspected and treated accordingly with intravenous eculizumab. Platelet count peaked at 417,000/mm3 within 7 days, kidney function normalized, and the patient was discharged 23 days after admission. Genetic analysis revealed two heterozygous rare variants of uncertain significance: p.(Gly759Arg) and p.(Gly110Arg) in the complement factor H (CFH) and factor I (CFI) genes, respectively. Given the diagnostic uncertainty, C5 inhibition (C5i) was discontinued, but HUS relapsed 3.5 months later following a febrile upper respiratory tract infection. This case highlights the diagnostic challenge of discriminating aHUS when STEC infection coexists. As variants in complement regulatory genes (including pathogenic, likely pathogenic, or variants of unknown significance) are not uncommon in the general population, careful monitoring of platelet count using disease-specific reference trajectories may represent a clinically useful tool to detect early deviation from classical STEC-HUS evolution and prompt timely C5i, preventing severe consequences.
2026-07-08 | [Shiga toxin-producing Escherichia coli O80 pyelonephritis complicated by hemolytic uremic syndrome in a 3-year-old girl].
Typical hemolytic uremic syndrome (HUS) in children most often follows a gastrointestinal infection caused by Shiga toxin-producing Escherichia coli (STEC). In STEC gastrointestinal infections, antibiotic therapy is generally not recommended because of the risk of increased Shiga toxin release. Extraintestinal STEC infections, including urinary tract infections, are rare and raise a therapeutic dilemma. We report the case of a 3-year-old girl with acute pyelonephritis who subsequently developed HUS despite appropriate antibiotic therapy. Urine and stool cultures identified a Shiga toxin-producing E. coli O80 strain. This case highlights that STEC may cause urinary tract infections, a rare presentation that can precede HUS, and emphasizes the complexity of therapeutic management.
other
2026-05-27 | Treatment of Shiga toxin-producing E. coli infection by CRISPR-Cas-targeted cleavage of the Shiga toxin gene in animal models.
Escherichia coli is not only a ubiquitous gut commensal but also an opportunistic pathogen responsible for severe intestinal and extraintestinal infections. Shiga toxin-producing E. coli (STEC) poses a notable public health threat, particularly in children, where infections can lead to bloody diarrhea and progress to hemolytic uremic syndrome, a life-threatening condition with long-term complications. Antibiotics are contraindicated in STEC infections because of their potential to induce prophages carrying Shiga toxin (stx) genes, triggering toxin production. Here, we developed a CRISPR-based antimicrobial strategy using a Cas12 nuclease to selectively eliminate O157 STEC clinical isolates, cleaving more than 99% of stx variants, and prevent toxin release. To enable targeted delivery, we engineered a bacteriophage-derived capsid to specifically transfer a nonreplicative DNA payload to E. coli O157, preventing its dissemination. Our therapeutic candidate, EB003, reduced bacterial burden in a murine STEC colonization model. Moreover, EB003 mitigated clinical symptoms, abrogated Stx-mediated toxicity, and accelerated epithelial repair at therapeutically relevant doses in an infant rabbit disease model. These findings demonstrate the potential of CRISPR-based antimicrobials for treating STEC infections and support further clinical development of EB003 as a precision therapeutic against antibiotic-refractory bacterial pathogens.
2025-11-07 | Spatially and Multivalent Matched Neutralizing Aptamer-Based DNA Nanostructure Alleviates Shiga Toxin Type 2 Infection.
Shiga toxin type 2 (Stx2) is a risk factor for acute bloody diarrhea and hemolytic uremic syndrome, which has posed a major threat to global public health. Currently, there is a lack of effective strategies to combat Stx2 infection. Herein, according to the structural characteristics and infection mechanism of Stx2, we have designed a structure mediated by self-assembling DNA tetrahedral nanoframes (TDN), which can orderly assemble three neutral aptamers (TDN-S) to prevent Stx2 from entering cells and inhibit Stx2 infection. The neutralizing aptamers SA, SB, and SC can respectively bind to the three sites (sites 1, 2, and 3) on the Stx2 B subunit, which coincidentally occupy the binding sites of Stx2 and Gb3 receptor. Benefiting from the simultaneous capture of three active sites, spatial matching, and the steric hindrance effect, TDN-S exhibits excellent neutralization efficiency against Stx2. The inhibition ability of Stx2 infection in vitro was evaluated by cell viability, intracellular fluorescence imaging, and ROS levels, and the inhibition rate was as high as 80.44%. The TDN-S significantly reduces the damage to the liver, kidneys, and intestines and the inflammatory response in vivo. Overall, the neutralization strategy with multimodal interaction provides a new way to alleviate the Stx2 toxicity and serves as a model for other wide-range toxin-like inhibitions.
2025-02-28 | Treatment of STEC infection via CRISPR-Cas targeted cleavage of the Shiga toxin gene in animal models
Abstract Escherichia coli is a ubiquitous gut commensal but also an opportunistic pathogen responsible for severe intestinal and extra-intestinal infections. Shiga toxin-producing E. coli (STEC) pose a significant public health threat, particularly in children, where infections can lead to bloody diarrhea and progress to hemolytic uremic syndrome (HUS), a life-threatening condition with long-term complications. Antibiotics are contraindicated in STEC infections due to their potential to induce prophages carrying Shiga toxin ( stx) genes, triggering toxin production. Here, we present a CRISPR-based antimicrobial strategy that selectively targets and eliminates O157 STEC clinical isolates while preventing toxin release. We designed a Cas12 nuclease to cleave >99% of all stx variants found in O157 strains, leading to bacterial killing and suppression of toxin production. To enable targeted delivery, we engineered a bacteriophage-derived capsid to specifically transfer a non-replicative DNA payload to E. coli O157, preventing its dissemination. In a mouse STEC colonization model, our therapeutic candidate, EB003, reduced bacterial burden by a factor of 3×10 3 . In an infant rabbit disease model, EB003 mitigated clinical symptoms, abrogated stx-mediated toxicity, and accelerated epithelial repair at therapeutically relevant doses. These findings demonstrate the potential of CRISPR-based antimicrobials for treating STEC infections and support further clinical development of EB003 as a precision therapeutic against antibiotic-refractory bacterial pathogens.
2025-01-08 | CRISPR/Cas Systems as Diagnostic and Potential Therapeutic Tools for Enterohemorrhagic Escherichia coli.
Following its discovery as an adaptive immune system in prokaryotes, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) system has been developed into a multifaceted genome editing tool. This review compiles findings aimed at implementation of this technology for selective elimination or attenuation of enterohemorrhagic Escherichia coli (EHEC). EHEC are important zoonotic foodborne pathogens that cause hemorrhagic colitis and can progress to the life-threatening hemolytic uremic syndrome (HUS). Advancements in the application of CRISPR methodology include laboratory detection and identification of EHEC, genotyping, screening for pathogenic potential, and engineering probiotics to reduce microbial shedding by cattle, the primary source of human infection. Genetically engineered phages or conjugative plasmids have been designed to target and inactivate genes whose products are critical for EHEC virulence.
2024-10-26 | Gb3 trisaccharide-bearing exosomes as a novel neutralizer for Shiga toxin type 1
Abstract Shiga toxin types 1 (Stx1) and 2 (Stx2), produced by Shiga toxin-producing Escherichia coli (STEC) and Shigella dysenteriae , are key virulence factors responsible for severe foodborne diseases, such as hemorrhagic colitis and hemolytic uremic syndrome (HUS). The receptors for Stxs are Gb3 and P1 glycotope, which contain the Galα1→4Gal epitope and are synthesized by human α1,4-galactosyltransferase (A4galt). Stx-related infections pose a global public health challenge, owing to the limited therapeutic options due to the restricted use of antibiotics. Therefore, there is an urgent need to develop novel therapeutic strategies. This study proposes an innovative strategy utilizing exosomes derived from CHO-Lec2 cells, which were modified with Functional-Spacer-Lipid (FSL) conjugates bearing the Gb3 carbohydrate epitope (exo-Gb3-FSL). Flow cytometry analysis confirmed the presence of Galα1→4Gal disaccharides on exo-Gb3-FSL constructs, enabling them to bind Stx1. Moreover, using CHO-Lec2 cells evaluated the ability of exo-Gb3-FSL agents to bind Stx1 and protect these cells from Stx1-mediated cytotoxicity. For Stx1-treated CHO-Lec2 cells, increased cell survival was observed when using 25 µM exo-Gb3-FSL constructs, compared to control cells. These findings highlight the potential of exosome-based anti-Stx1 agents as promising alternatives to conventional therapies. This innovative strategy may provide novel directions for studies on Stx1 neutralization, offering a valuable strategy for the treatment of Stx-related diseases. Highlights - Exo-Gb3-FSL constructs hold Stx1 binding Galα1→4Gal epitope. - Stx1 was effectively bound by exo-Gb3-FSL constructs. - Exo-Gb3-FSL protected CHO-Lec2 cells from Stx1. - Exo-Gb3-FSL is a promising anti-Stx1 agent.
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Drug Discovery Landscape
6 orphan drug designations for Shiga toxin-associated hemolytic uremic syndrome.
6 orphan drug designations for Shiga toxin-associated hemolytic uremic syndrome.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
Phage-derived, non-replicative delivery vector carrying a DNA payload encoding an RNA-guided nuclease that targets stx genes of Shiga toxin-producing Escherichia coli (STEC) | gene therapies | FDA | — | Eligo Bioscience SA |
neutralizing equine anti-Stx hyperimmune immunoglobulin F(ab')2 fragment | antibodies | FDA | Inmunova SA | |
eculizumab | antibodies | FDA | Alexion Pharmaceuticals, Inc. | |
chimeric monoclonal antibodies, c-alphaStx2 | antibodies | FDA | — | Taro Pharmaceuticals Inc. |
humanized monoclonal antibody against Shiga-like toxin II | antibodies | FDA | — | Teijin America, Inc. |
Synsorb Pk | other | FDA | Synsorb Biotech Inc. |
“Terminated” – programs with discontinued clinical trials, or with no updates reported for 5 years after completion or 12 years after the last trial started.
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