Overview of pathogenic Escherichia coli, with a focus on Shiga toxin-producing serotypes, global outbreaks (1982-2024) and food safety criteria.

Classification of pathogenic E. coli has been focused either in mammalian host or infection site, which offers limited resolution. This review presents a comprehensive framework for classifying all E. coli branches within a single, unifying figure. This approach integrates established methods based on virulence factors, serotypes and clinical syndromes, offering a more nuanced and informative perspective on E. coli pathogenicity. The presence of the LEE island in pathogenic E. coli is a key genetic marker differentiating EHEC from STEC strains. The coexistence of stx and eae genes within the bacterial genome is a primary characteristic used to distinguish STEC from other pathogenic E. coli strains. The presence of the inv plasmid, Afa/Dr adhesins, CFA-CS-LT-ST and EAST1 are key distinguishing features for identifying pathogenic E. coli strains belonging to EIEC, DAEC, ETEC and EAEC pathotypes respectively. Food microbiological criteria differentiate pathogenic E. coli in food matrices. 'Zero-tolerance' applies to most ready-to-eat (RTE) foods due to high illness risk. Non-RTE foods' roles may allow limited E. coli presence, which expose consumers to potential risk; particularly from the concerning Shiga toxin-producing E. coli (STEC) strains, which can lead to life-threatening complications in humans, including haemolytic uremic syndrome (HUS) and even death in susceptible individuals. These findings suggest that decision-makers should consider incorporating the separate detection of STEC serotypes into food microbiological criteria, in addition to existing enumeration methods. Contamination of STEC is mainly linked to food consumption, therefore, outbreaks of E. coli STEC has been reviewed here and showed a link also to water as a potential contamination route. Since their discovery in 1982, over 39,787 STEC cases associated with 1,343 outbreaks have been documented. The majority of these outbreaks occurred in the Americas, followed by Europe, Asia and Africa. The most common serotypes identified among the outbreaks were O157, the 'Big Six' (O26, O45, O103, O111, O121, and O145), and other serotypes such as O55, O80, O101, O104, O116, O165, O174 and O183. This review provides valuable insights into the most prevalent serotypes implicated in STEC outbreaks and identifies gaps in microbiological criteria, particularly for E. coli non-O157 and non-Big Six serotypes.

A review of conditions influencing fate of Shiga toxin-producing Escherichia coli O157:H7 in leafy greens.

The accuracy of predictive microbial models used in quantitative microbial risk assessment (QMRA) relies on the relevancy of conditions influencing growth or inactivation. The continued use of log-linear models in studies remains widespread, despite evidence that they fail to accurately account for biphasic kinetics or include parameters to account for the effect of environmental conditions within the model equation. Although many experimental studies detail conditions of interest, studies that do not do so lead to uncertainty in QMRA modeling because the applicability of the predictive microbial models to the conditions in the risk scenarios is questionable or must be extrapolated. The current study systematically reviewed 65 articles that provided quantitative data and documented the conditions influencing the inactivation or growth of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in leafy greens. The conditions were identified and categorized as environmental, biological, chemical, and/or processing. Our study found that temperature (n = 37 studies) and sanitizing and washing procedures (n = 12 studies) were the most studied conditions in the farm-to-table continuum of leafy greens. In addition, relative humidity was also established to affect growth and inactivation in more than one stage in the continuum. This study proposes the evaluation of the interactive effects of multiple conditions in processing and storage stages from controlled experiments as they relate to the fate of STEC O157:H7 in leafy greens for future quantitative analysis.

An outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 associated with contaminated lettuce and the cascading risks from climate change, the United Kingdom, August to September 2022.

Shiga-toxin producing Escherichia coli (STEC) O157 is a food-borne pathogen which causes gastrointestinal illness in humans. Ruminants are considered the main reservoir of infection, and STEC exceedance has been associated with heavy rainfall. In September 2022, a large outbreak of STEC O157:H7 was identified in the United Kingdom (UK). A national-level investigation was undertaken to identify the source of the outbreak and inform risk mitigation strategies. Whole genome sequencing (WGS) was used to identify outbreak cases. Overall, 259 cases with illness onset dates between 5 August and 12 October 2022, were confirmed across the UK. Epidemiological investigations supported a UK grown, nationally distributed, short shelf-life food item as the source of the outbreak. Analytical epidemiology and food chain analysis suggested lettuce as the likely vehicle of infection. Food supply chain tracing identified Grower X as the likely implicated producer. Independent of the food chain investigations, a novel geospatial analysis triangulating meteorological, flood risk, animal density and land use data was developed, also identifying Grower X as the likely source. Novel geospatial analysis and One Health approaches are potential tools for upstream data analysis to predict and prevent contamination events before they occur and to support evidence generation in outbreak investigations.

Detection of EPEC and STEC strains isolated from children with diarrhea in Argentina.

Rectal swabs (122) from pediatric patients were analyzed by polymerase chain reaction (PCR) for the detection of EPEC and STEC. STEC isolates were tested for the presence of stx1, stx2, eae, saa and ehxA. All eae-positive samples were tested for the presence of bfpA, and antigen O was determined using the agglutination test. Int1 and Int2 were detected to identify the presence of integrons class 1 and 2, respectively. Escherichia coli was detected in 68% of the samples, of which 18.8% were STEC (2.45%) and EPEC (16.3%). Serogroups STEC O145 and EPEC O130, O113 and O157 were observed, while three strains were non-typable. None of the EPEC strains carrying tbfpA and class 1 and 2 integrons was detected in any of the samples. The results obtained are important considering the virulence profiles found in the isolated EPEC and STEC strains and the serogroups associated with disease in humans.

Molecular and in silico analyses for detection of Shiga toxin-producing Escherichia coli (STEC) and highly pathogenic enterohemorrhagic Escherichia coli (EHEC) using genetic markers located on plasmid, O Island 57 and O Island 71.

BACKGROUND: Due to the diversity of Shiga toxin-producing Escherichia coli (STEC) isolates, detecting highly pathogenic strains in foodstuffs is challenging. Currently, reference protocols for STEC rely on the molecular detection of eae and the stx1 and/or stx2 genes, followed by the detection of serogroup-specific wzx or wzy genes related to the top 7 serogroups. However, these screening methods do not distinguish between samples in which a STEC possessing both determinants are present and those containing two or more organisms, each containing one of these genes. This study aimed to evaluate ecf1, Z2098, Z2099, and nleA genes as single markers and their combinations (ecf1/Z2098, ecf1/Z2099, ecf1/nleA, Z2098/Z2099, Z2098/nleA, and Z2099/nleA) as genetic markers to detect potentially pathogenic STEC by the polymerase chain reaction (PCR) in 96 animal samples, as well as in 52 whole genome sequences of human samples via in silico PCR analyses. RESULTS: In animal isolates, Z2098 and Z2098/Z2099 showed a strong association with the detected top 7 isolates, with 100% and 69.2% of them testing positive, respectively. In human isolates, Z2099 was detected in 95% of the top 7 HUS isolates, while Z2098/Z2099 and ecf1/Z2099 were detected in 87.5% of the top 7 HUS isolates. CONCLUSIONS: Overall, using a single gene marker, Z2098, Z2099, and ecf1 are sensitive targets for screening the top 7 STEC isolates, and the combination of Z2098/Z2099 offers a more targeted initial screening method to detect the top 7 STEC isolates. Detecting non-top 7 STEC in both animal and human samples proved challenging due to inconsistent characteristics associated with the genetic markers studied.

IgG-immunoadsorptions and eculizumab combination in STEC-hemolytic and uremic syndrome pediatric patients with neurological involvement.

BACKGROUND: Neurological complications pose a significant threat in pediatric hemolytic and uremic syndrome (HUS) resulting from infections with Shiga toxin-producing Escherichia coli (STEC), with no established treatment. The involvement of complement activation in the pathogenesis of STEC-HUS is acknowledged, and eculizumab (ECZ), a terminal complement blocker, has been documented in several pediatric series with inconsistent results. Antibody-mediated mechanisms have also been suggested, with IgG-immunoadsorption (IgIA) showing promise in adults with neurological complications. We aimed to assess the benefit of combining IgIA with ECZ in pediatric patients with neurological STEC-HUS compared to patients treated with ECZ alone or supportive care. METHODS: Multicenter retrospective study conducted on pediatric patients (< 18 years) with neurological STEC-HUS treated with IgIA + ECZ or ECZ alone from 2010 to 2020 in France. A historical cohort treated with supportive care served as controls. Primary outcome included survival and neurological evaluation at 1-year follow-up (dichotomized as normal vs. abnormal). RESULTS: A total of 42 children were included: 18 treated with IgIA + ECZ, 24 with ECZ alone, and 27 with supportive care. Although there was no significant difference in survival between groups, three deaths occurred in the control group in the acute phase, while none was reported in both the IgIA + ECZ and ECZ alone groups, despite presenting with more severe neurological symptoms for IgIA + ECZ patients. No significant association was found between treatment group and 1-year neurological evaluation after adjustment for age, sex, and initial neurological presentation. CONCLUSIONS: Systematic association of IgIA + ECZ is not supported for all neurological STEC-HUS pediatric patients; potential rescue therapy for severe cases warrants consideration.

The impact of climate variation on the spread of Shiga toxin-producing E. coli.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) is influenced by seasonality, but there is limited understanding of how specific climatic variables contribute to disease spread. This information aids in understanding disease transmission dynamics and could potentially inform public health modeling. METHODS: This retrospective cohort study analyzed public health data from Ontario, Canada, between 2012 and 2021, along with historical climate data from Environment Canada. We employed Seasonal Autoregressive Integrated Moving Average (S-ARIMA) models to assess how temperature and precipitation impact the incidence of STEC infections, measured per 10,000,000 population. RESULTS: The study included 1658 confirmed STEC cases. A significant correlation was found between STEC incidence and climatic variables. Each degree Celsius increase in maximum temperature was associated with a rise of 3 STEC cases per 10,000,000 population (Centers for Disease Control and Prevention (2024)). Additionally, each millimeter of increased precipitation correlated with an increase of 1.1 cases per 10,000,000 population. CONCLUSIONS: The findings demonstrate a significant impact of temperature and precipitation on STEC transmission, highlighting the importance of integrating meteorological data into public health surveillance. This integration may help inform public health responses and support healthcare systems in planning for future outbreaks. Further studies are needed to refine predictive models and develop effective early warning systems for clinical settings.

Shiga toxin-producing Escherichia coli infection as a precipitating factor for atypical hemolytic-uremic syndrome.

BACKGROUND: Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by intravascular hemolysis. It can be classified as either typical, primarily caused by Shiga toxin-producing Escherichia coli (STEC) infection, or as atypical HUS (aHUS), which results from uncontrolled complement activation. METHODS: We report the case of a 9-year-old boy with aHUS due to compound heterozygous complement factor H-related genes (CFHR) 1/3 and CFHR1-CFHR4 deletions, leading to the development of anti-complement factor H (CFH) autoantibodies. The patient presented nephrological and neurological thrombotic microangiopathy with STEC positivity. Additionally, we provide an extensive literature review of aHUS cases initially classified as typical. RESULTS: A total of 11 patients were included, 73% of whom were pediatric. Kidney replacement therapy was required in 73% of patients. The recurrence rate was 55%. All cases were found positive for pathological variants of the complement system genes. The most commonly implicated gene was CFH, while the CFHR genes were involved in 36% of cases, although none exhibited anti-CFH autoantibodies. Anti-complement therapy was administered in 54% of cases, and none of the patients who received it early progressed to kidney failure. CONCLUSIONS: STEC infection does not exclude aHUS diagnosis, and early use of anti-complement therapy might be reasonable in life-threatening conditions. Genetic testing can be helpful in patients with atypical presentations and can confirm the necessity of prolonged anti-complement therapy.

Detection of Shiga toxin-producing Escherichia coli in dairy cows: genetic characterization and inhibition of adherence by cattle anti-STEC antibodies to HEp-2 cell.

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen associated with severe disease. Cattle are recognized as the primary animal reservoir of STEC. This study reports the occurrence and characterization of STEC from dairy cows and evaluates the inhibition of adherence by cattle anti-STEC antibodies to the HEp-2 cell. From 151 samples, 30% (n = 45) were positive for stx by PCR screening (25.21% of dairy cows and 46.8% of growing calves). From these positive samples, 17 STEC isolates were characterized. In dairy cows, 3 out of 17 samples carried stx2, 3 out of 17 possessed stx1, and 2 out of 17 carried stx1/stx2. In growing cows, 8 out of 17 samples carried stx1 and 1 out of 17 carried stx1/stx2. Other virulence factors such as ehxA, saa, iha, cah, and eae were detected. The strains were typed into 3 E. coli O groups (O26, O91, and O130). The analysis of the HEp-2 adherence assays indicated that all serum from both cattle categories presented high levels of inhibition of adherence. Considering the severity of the symptoms caused by STEC in humans, searching for factors influencing the colonization of STEC in cattle would help identify strategies to avoid transmission and STEC infection.

A Health Threat from Farm to Fork: Shiga Toxin-Producing Escherichia coli Co-Harboring blaNDM-1 and mcr-1 in Various Sources of the Food Supply Chain.

The dissemination of resistant pathogens through food supply chains poses a significant public health risk, spanning from farm to fork. This study analyzed the distribution of Shiga toxin-producing Escherichia coli (STEC) across various sources within the animal-based food supply chain. A total of 500 samples were collected from livestock, poultry, the environment, fisheries, and dairy. Standard microbiological procedures were employed to isolate and identify E. coli isolates, which were further confirmed using MALDI-TOF and virulence-associated genes (VAGs) such as stx1, stx2, ompT, hylF, iutA, fimH, and iss. The phenotypic resistance patterns of the isolates were determined using the disc diffusion method, followed by molecular identification of antibiotic resistance genes (ARGs) through PCR. STEC were subjected to PCR-based O typing using specific primers for different O types. Overall, 154 (30.5%) samples were confirmed as E. coli, of which 77 (50%) were multidrug-resistant (MDR) E. coli. Among these, 52 (67.53%) isolates exhibited an array of VAGs, and 21 (40.38%) were confirmed as STEC based on the presence of stx1 and stx2. Additionally, 12 out of 52 (23.07%) isolates were identified as non-O157 STEC co-harbouring mcr-1 and blaNDM-1. O26 STEC was found to be the most prevalent among the non-O157 types. The results suggest that the detection of STEC in food supply chains may lead to serious health consequences, particularly in developing countries with limited healthcare resources.

A hurdle strategy based on the combination of non-thermal treatments to control diarrheagenic E. coli in cheese.

This study aimed to assess the efficacy of a multi-hurdle process combining mild High Hydrostatic Pressure (HHP) treatments and Thyme Oil (TO) edible films as a non-thermal method to combat pathogenic E. coli (aEPEC and STEC) in raw cow's-milk cheese stored at 7 °C and packaged under modified atmosphere. Changes in headspace atmosphere of cheese packs and treatment effects on Lactic Acid Bacteria (LAB) counts and diarrheagenic E. coli strains (aEPEC and STEC) were evaluated over a 28 d storage period. The results demonstrated that the combined treatment exhibited the most significant antimicrobial effect against both strains compared to individual treatments, achieving reductions of 4.30 and 4.80 log cfu/g after 28 d of storage for aEPEC and STEC, respectively. Notably, the synergistic effect of the combination treatment resulted in the complete inactivation of intact cells for STEC and nearly completed inactivation for aEPEC by the end of the storage period. These findings suggest that the combination of HHP with selected hurdles could effectively enhance microbial inactivation capacity, offering promising alternatives for improving cheese safety without affecting the starter microbiota.

Transition to Whole Genome Sequencing Surveillance: The Impact on National Outbreak Detection and Response for Listeria monocytogenes, Salmonella, Shiga Toxin-Producing Escherichia coli, and Shigella Clusters in Canada, 2015-2021.

Between 2017 and 2019, pulsed-field gel electrophoresis was replaced by whole genome sequencing (WGS) for identifying enteric disease clusters in Canada. The number and characteristics of all clusters of Listeria monocytogenes, Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Shigella spp. between 2015 and 2021 were analyzed. Following the transition to WGS, an increase in the number of Salmonella, STEC, and Shigella clusters was noted, whereas the number of clusters of L. monocytogenes decreased. Unlike previous subtyping methods, WGS provided increased resolution to identify discrete clusters of Salmonella Enteritidis. This led to the identification of a number of outbreaks linked to frozen raw breaded chicken products and ultimately a change in food safety policy to reduce the number of illnesses associated with these products. Other pathogens did not experience a similar increase in the number of outbreaks detected. Although WGS did provide increased confidence in the genetic relatedness of cases and isolates, challenges remained in collecting epidemiological data to link these illnesses to a common source.

A rapid on-site loop-mediated isothermal amplification technology as an early warning system for the detection of Shiga toxin-producing Escherichia coli in water.

Shiga toxin-producing Escherichia coli (STEC) is an important waterborne pathogen capable of causing serious gastrointestinal infections with potentially fatal complications, including haemolytic-uremic syndrome. All STEC serogroups harbour genes that encode at least one Shiga toxin (stx1 and/or stx2), which constitute the primary virulence factors of STEC. Loop-mediated isothermal amplification (LAMP) enables rapid real-time pathogen detection with a high degree of specificity and sensitivity. The aim of this study was to develop and validate an on-site portable diagnostics workstation employing LAMP technology to permit rapid real-time STEC detection in environmental water samples. Water samples (n=28) were collected from groundwater wells (n=13), rivers (n=12), a turlough (n=2) and an agricultural drain (n=1) from the Corrib catchment in Galway. Water samples (100 ml) were passed through a 0.22 µm filter, and buffer was added to elute captured cells. Following filtration, eluates were tested directly using LAMP assays targeting stx1, stx2 and E. coli phoA genes. The portable diagnostics workstation was used in field studies to demonstrate the on-site testing capabilities of the instrument. Real-time PCR assays targeting stx1 and stx2 genes were used to confirm the results. The limit of detection for stx1, stx2 and phoA LAMP assays were 2, 2 and 6 copies, respectively. Overall, stx1, stx2 and phoA genes were detected by LAMP in 15/28 (53.6 %), 9/28 (32.2 %) and 24/28 (85.7 %) samples, respectively. For confirmation, the LAMP results for stx1 and stx2 correlated perfectly (100 %) with those obtained using PCR. The portable diagnostics workstation exhibited high sensitivity throughout the on-site operation, and the average time from sample collection to final result was 40 min. We describe a simple, transferable and efficient diagnostic technology for on-site molecular analysis of various water sources. This method allows on-site testing of drinking water, enabling evidence-based decision-making by public health and water management authorities.

Percutaneous transcatheter treatment for partial anomalous pulmonary right venous connection to the superior caval vein without atrial septal defect.

We developed technique similar to transcatheter treatment for superior sinus venosus defects to treat a patient with a Partial Anomalous Pulmonary Venous Connection of the right upper pulmonary veins (RUPV) without an atrial septal defect. A double transseptal puncture was performed, and the left atrium (LA) was connected with the RUPV using a covered stent. The blood flow from the superior vena cava was directed to the right atrium (RA) using a second covered stent.

Using a customized telescoped stent complex in the percutaneous treatment of a residual superior sinus venosus defect.

The management of superior sinus venosus defects (SVD) via transcatheter covered stent (CS) placement is becoming an acceptable alternative to open heart surgery. Though the medium-term success of this procedure has been described, residual shunting from damage to the covering of the implanted stents, use of stents which are too short and unanticipated shortening of stents may result in immediate or short-term procedural failure. In such cases, placement of a second CS may be required to address a residual defect. Preprocedural prediction of the length of stent required for residual leak treatment may not be as accurate as predicting the required stent length in a native defect, meaning that compassionate use applications to facilitate acquiring non-standard stent and balloon combinations may not be practical. We present a successful case of residual SVD closure using a novel sutured telescoping stent technique. Further collaboration with industry should encourage regulatory approval of longer CS, to mitigate the need for potentially unpredictable modifications such as this.

Occurrence, serotypes and virulence characteristics of Shiga toxin-producing and Enteropathogenic Escherichia coli isolates from dairy cattle in South Africa.

Shiga toxin-producing and Enteropathogenic Escherichia coli are foodborne pathogens commonly associated with diarrheal disease in humans. This study investigated the presence of STEC and EPEC in 771 dairy cattle fecal samples which were collected from 5 abattoirs and 9 dairy farms in South Africa. STEC and EPEC were detected, isolated and identified using culture and PCR. Furthermore, 339 STEC and 136 EPEC isolates were characterized by serotype and major virulence genes including stx1, stx2, eaeA and hlyA and the presence of eaeA and bfpA in EPEC. PCR screening of bacterial sweeps which were grown from fecal samples revealed that 42.2% and 23.3% were STEC and EPEC positive, respectively. PCR serotyping of 339 STEC and 136 EPEC isolates revealed 53 different STEC and 19 EPEC serotypes, respectively. The three most frequent STEC serotypes were O82:H8, OgX18:H2, and O157:H7. Only 10% of the isolates were classified as "Top 7" STEC serotypes: O26:H2, 0.3%; O26:H11, 3.2%; O103:H8, 0.6%; and O157:H7, 5.9%. The three most frequent EPEC serotypes were O10:H2, OgN9:H28, and O26:H11. The distribution of major virulence genes among the 339 STEC isolates was as follows: stx1, 72.9%; stx2, 85.7%; eaeA, 13.6% and hlyA, 69.9%. All the 136 EPEC isolates were eaeA-positive but bfpA-negative, while 46.5% carried hlyA. This study revealed that dairy cattle are a major reservoir of STEC and EPEC in South Africa. Further comparative studies of cattle and human STEC and EPEC isolates will be needed to determine the role played by dairy cattle STEC and EPEC in the occurrence of foodborne disease in humans.Please kindly check and confirm the country and city name in affiliation [6].This affiliation is correct.Please kindly check and confirm the affiliationsConfirmed. All Affiliations are accurate.

The Use of Antimicrobial Washes to Inactivate Shiga Toxin-Producing Escherichia coli from In-Shell Pecans and Wash Water Contaminated by Different Inoculation Routes.

In-shell pecans are typically harvested after falling from trees to the ground, presenting a potential route of contamination of foodborne pathogens from soil contact. In-shell pecans are often subjected to various processing or washing steps prior to being shelled. This study determined Shiga toxin-producing Escherichia coli (STEC) reductions after treatment with antimicrobial washes on direct and soil-inoculated in-shell pecans and evaluated the cross-contamination potential of the spent pecan washes after treatment. Pecans were directly and soil-inoculated with an STEC cocktail (O157:H7, O157:NM, O121, O26). Direct inoculation was achieved by spraying the STEC cocktail on the pecans. For soil-inoculation pecans, autoclaved soil was sprayed with the STEC cocktail, homogenized for 2 min, and used to coat in-shell pecans. Inoculated pecans were washed in treatments of 2% lactic acid (LA), 1,000 ppm free chlorine (sodium hypochlorite; NaClO), hot water (HW; 85 ± 2 °C), or ambient water (C [control]; 18 ± 2 °C) for 2, 5, and 10 min and diluted to enumerate STEC populations. After treatments, 100 mL of the spent wash was vacuum filtered through a 0.45-µm membrane and plated on selective agar. HW significantly reduced STEC populations from pecans with and without soil regardless of treatment time (p < 0.05), NaClO reduced STEC populations more than the ambient control wash on directly inoculated pecans, but there were no significant differences between STEC reductions from ambient water (C), LA, and NaClO treatments on soil-inoculated pecans (p > 0.05). Larger STEC populations were enumerated from ambient water wash compared to the antimicrobial washes (p < 0.05). The HW, LA, and NaClO treatments were effective at maintaining the quality of the wash water, with STEC levels being generally at or below the detection limit (<1 CFU/100 mL), while HW was the most effective at reducing STEC from in-shell pecans with and without a soil coating (>5-log CFU/mL reductions).

Shiga Toxin-Producing Escherichia coli Strains from Romania: A Whole Genome-Based Description.

The zoonotic Shiga toxin-producing Escherichia coli (STEC) group is unanimously regarded as exceptionally hazardous for humans. This study aimed to provide a genomic perspective on the STEC recovered sporadically from humans and have a foundation of internationally comparable data. Fifty clinical STEC isolates, representing the culture-confirmed infections reported by the STEC Reference Laboratory between 2016 and 2023, were subjected to whole-genome sequencing (WGS) analysis and sequences were interpreted using both commercial and public free bioinformatics tools. The WGS analysis revealed a genetically diverse population of STEC dominated by non-O157 serogroups commonly reported in human STEC infections in the European Union. The O26:H11 strains of ST21 lineage played a major role in the clinical disease resulting in hospitalisation and cases of paediatric HUS in Romania surpassing the O157:H7 strains. The latter were all clade 7 and mostly ST1804. Notably, among the Romanian isolates was a stx2a-harbouring cryptic clade I strain associated with a HUS case, stx2f- and stx2e-positive strains, and hybrid strains displaying a mixture of intestinal and extraintestinal virulence genes were found. As a clearer picture emerges of the STEC strains responsible for infections in Romania, further surveillance efforts are needed to uncover their prevalence, sources, and reservoirs.

Vacation in Egypt associated with Shiga toxin-producing Escherichia coli infection in children and adolescents, northern Italy, 2023.

BackgroundHaemolytic uremic syndrome (HUS) is a severe complication of infection with Shiga toxin-producing Escherichia coli (STEC). Although the reservoirs of STEC are known, the source of the infection of sporadic cases is often unknown. In 2023, we observed several cases of bloody diarrhoea with STEC infection in children and adolescents returning from vacations.AimWe aimed to explore the association between travel and bloody diarrhoea with STEC infection in children and adolescents.MethodsWe included all children and adolescents with bloody diarrhoea with STEC infection identified in 2023 by the ItalKid-HUS Network surveillance system in northern Italy. We interviewed children's families and sent a questionnaire on recent travels abroad. The exposure time was between 3 days after arrival abroad and 5 days after return home. A self-controlled case series (SCCS) design was used in the analysis.ResultsOf the 43 cases, 11 developed HUS. Twenty-three cases did not travel abroad, while 20 had travelled to several destinations. The incidence rate ratio (IRR) associated with travel to Egypt was 88.6 (95% confidence interval (CI): 17.0-462). Serotype analysis excluded the possibility of a single strain causing the infections. We did not find the source of the infections.ConclusionThere is an elevated risk of acquiring STEC infection with bloody diarrhoea and HUS associated with travel to Egypt. Specific investigations to identify the source are needed to implement effective preventive measures.

Antibiotic Resistance and Genomic Analysis of Shiga Toxin-Producing Escherichia coli from Dairy Cattle, Raw Milk, and Farm Environment in Shaanxi Province, China.

To investigate the epidemiology of Shiga toxin-producing Escherichia coli (STEC) in dairy cattle, 975 samples (185 feces, 34 silage, 36 cattle drinking water, 360 raw milk, and 360 teat skin swabs) were collected from two dairy farms in Baoji and Yangling, Shaanxi Province, China, and were screened for STEC. Whole-genome sequencing was used to analyze the genomic characteristics and potential transmission of STEC isolates. A total of 32 samples were contaminated with STEC, including 4.0% (19/479) in Farm A and 2.6% (13/496) in Farm B. Compared with adult cows (4.5%), nonadult cows had a higher rate (21.3%) of STEC colonization. A total of 14 serotypes and 11 multilocus sequence typing were identified in 32 STEC isolates, among which O55:H12 (25.0%) and ST101 (31.3%) were the most predominant, respectively. Six stx subtypes/combinations were identified, including stx1a (53.1%), stx2g (15.6%), stx2d, stx2a+stx2d, stx1a+stx2a (6.3%, for each), and stx2a (3.1%). Of 32 STEC isolates, 159 virulence genes and 27 antibiotic resistance genes were detected. Overall, STEC isolates showed low levels of resistance to the 16 antibiotics tested (0-40.6%), with most common resistance to ampicillin (40.6%). The phylogenetic analysis confirmed that STEC in the gut of cattle can be transmitted through feces. The results of this study help to improve our understanding of the epidemiological aspects of STEC in dairy cattle and provide early warning and control of the prevalence and spread of the bacterium.