Asymptomatic long-term carriers of Shigatoxin producing Escherichia coli (STEC) are regarded as potential source of STEC-transmission. The prevention of outbreaks via onward spread of STEC is a public health priority. Accordingly, health authorities are imposing far-reaching restrictions on asymptomatic STEC carriers in many countries. Various STEC strains may cause severe hemorrhagic colitis complicated by life-threatening hemolytic uremic syndrome (HUS), while many endemic strains have never been associated with HUS. Even though antibiotics are generally discouraged in acute diarrheal STEC infection, decolonization with short-course azithromycin appears effective and safe in long-term shedders of various pathogenic strains. However, most endemic STEC-strains have a low pathogenicity and would most likely neither warrant antibiotic decolonization therapy nor justify social exclusion policies. A risk-adapted individualized strategy might strongly attenuate the socio-economic burden and has recently been proposed by national health authorities in some European countries. This, however, mandates clarification of strain-specific pathogenicity, of the risk of human-to-human infection as well as scientific evidence of social restrictions. Moreover, placebo-controlled prospective interventions on efficacy and safety of, e.g., azithromycin for decolonization in asymptomatic long-term STEC-carriers are reasonable. In the present community case study, we report new observations in long-term shedding of various STEC strains and review the current evidence in favor of risk-adjusted concepts.

Shiga toxin-producing Escherichia (E.) coli (STEC) are zoonotic foodborne pathogens of significant public health importance. While ruminants are considered the main reservoir, wild animals are increasingly acknowledged as carriers and potential reservoirs of STEC. The aim of this study was to determine the occurrence of STEC in a total of 59 faecal samples of hunted wild boars (Sus scrofa) from two different regions in Switzerland (canton Thurgau in northern Switzerland and canton Ticino in southern Switzerland), and to characterise the isolates using a whole genome sequencing approach. After an enrichment step, Shiga-toxin encoding genes (stx) were detected by real-time PCR in 41 % (95 % confidence interval (95 %CI) 0,29 - 0,53) of the samples, and STEC were subsequently recovered from 22 % (95 %CI 0,13 - 0,34) of the same samples. Seven different serotypes and six different sequence types (STs) were found, with O146:H28 ST738 (n = 4) and O100:H20 ST2514 (n = 4) predominating. Subtyping of stx identified isolates with stx1c/stx2b (n = 1), stx2a (n = 1), stx2b (n = 6), and stx2e (n = 6). No isolate contained the eae gene, but all harboured additional virulence genes, most commonly astA (n = 10), hlyE (n = 9), and hra (n = 9). STEC O11:H5, O21:H21, and O146:H28 harboured virulence factors associated with extra-intestinal pathogenic E. coli (ExPEC), and STEC O100:H20 and O155:H26 possessed sta1 and/or stb and were STEC/enterotoxigenic E. coli (ETEC) hybrid pathotypes. Our results show that wild boars are carriers of STEC which may be distributed in the environment, possibly leading to the contamination of agricultural crops and water sources. The serogroups included STEC O146 which belongs to the most common non-O157 serogroups associated with human illness in Europe, with implications for public health. Since Stx2e-producing STEC have frequently been reported in swine and pork, STEC O100:H20 harbouring stx2e in faeces of wild boars may be relevant to free-range systems of pig farming because of the potential risk of transmission events at the wildlife-livestock interface.
Shigtoxin produzierende Escherichia (E.) coli (STEC) sind zoonotische, lebensmittelbedingte Krankheitserreger von grosser Bedeutung für die öffentliche Gesundheit. Während Wiederkäuer als Hauptreservoir gelten, gelten Wildtiere zunehmend als Überträger und potenzielle Reservoire von STEC. Ziel dieser Studie war es, das Vorkommen von STEC in insgesamt 59 Kotproben von gejagten Wildschweinen (Sus scrofa) aus zwei verschiedenen Regionen der Schweiz (Kanton Thurgau in der Nordschweiz und Kanton Tessin in der Südschweiz) zu bestimmen und die Isolate mittels vollständiger Genomsequenzierung zu charakterisieren. Nach einem Anreicherungsschritt wurden Shigatoxin-kodierende Gene (stx) durch eine Echtzeit-PCR in 41 % (95 %-Konfidenzintervall (95 %-KI) 0,29 – 0,53) der Proben nachgewiesen, wovon aus 22 % (95 % CI 0,13 – 0,34) derselben Proben STEC gewonnen wurden. Es wurden sieben verschiedene Serotypen und sechs verschiedene Sequenztypen (STs) gefunden, wobei hauptsächlich O146:H28 ST738 (n = 4) und O100:H20 ST2514 (n = 4) vorkamen. Die stx-Subtypen stx1c/stx2b (n = 1), stx2a (n = 1), stx2b (n = 6) und stx2e (n = 6) wurden identifiziert. Kein Isolat enthielt das eae-Gen, aber alle enthielten zusätzliche Virulenzgene, am häufigsten astA (n = 10), hlyE (n = 9) und hra (n = 9). STEC O11:H5, O21:H21 und O146:H28 enthielten Virulenzfaktoren, die mit extraintestinalen pathogenen E. coli (ExPEC) assoziiert sind, und STEC O100:H20 und O155:H26 besassen sta1 und/oder stb und waren STEC/enterotoxigene E. coli (ETEC)-Hybridpathotypen. Unsere Ergebnisse zeigen, dass Wildschweine Träger von STEC sind und diese somit in der Umwelt verbreitet werden können, was möglicherweise auch zur Kontamination landwirtschaftlicher Nutzpflanzen und Wasserquellen führt. Zu den Serogruppen gehörte STEC O146, einer der häufigsten nicht-O157-Serogruppen, welche europaweit von kranken Menschen isoliert wird und ein Risiko für die öffentliche Gesundheit darstellt. Da bei Schweinen häufig über Stx2e-produzierende STEC berichtet wurde, kann angenommen werden, dass Wildschweine ein potenzielles Risiko zur Übertragung von STEC O100:H20, die stx2e enthalten, auf Schweine in Freilandhaltungssysteme darstellen könnten.
Les Escherichia (E.) coli producteurs de shiga-toxine (STEC) sont des agents pathogènes zoonotiques d’origine alimentaire qui revêtent une grande importance pour la santé publique. Alors que les ruminants sont considérés comme le principal réservoir, les animaux sauvages sont de plus en plus souvent reconnus comme porteurs et réservoirs potentiels de STEC. L’objectif de cette étude était de déterminer la présence de STEC dans un total de 59 échantillons fécaux de sangliers (Sus scrofa) chassés provenant de deux régions différentes de Suisse (canton de Thurgovie dans le nord de la Suisse et canton du Tessin dans le sud de la Suisse) et de caractériser les isolats en utilisant une approche de séquençage du génome entier. Après une étape d’enrichissement, les gènes codant pour la Shiga-toxine (stx) ont été détectés par PCR en temps réel dans 41% (intervalle de confiance à 95% (95%CI) 0,29 - 0,53) des échantillons, et les STEC ont ensuite été récupérés dans 22% (95%CI 0,13 - 0,34) des mêmes échantillons. Sept sérotypes différents et six types de séquence (ST) différents ont été trouvés, avec une prédominance de O146:H28 ST738 (n = 4) et O100:H20 ST2514 (n = 4). Le sous-typage des stx a permis d’identifier des isolats avec stx1c/stx2b (n = 1), stx2a (n = 1), stx2b (n = 6) et stx2e (n = 6). Aucun isolat ne contenait le gène eae, mais tous hébergeaient d’autres gènes de virulence, le plus souvent astA (n = 10), hlyE (n = 9) et hra (n = 9). Les STEC O11:H5, O21:H21 et O146:H28 présentaient des facteurs de virulence associés à des E. coli pathogènes extra-intestinaux (ExPEC), et les STEC O100:H20 et O155:H26 possédaient sta1 et/ou stb et étaient des pathotypes hybrides STEC/E. coli entérotoxinogène (ETEC).
Gli Escherichia coli (E. coli) che producono la tossina Shiga (STEC) sono patogeni di origine alimentare di notevole importanza per la salute pubblica. Anche se i ruminanti sono considerati come il serbatoio principale, gli animali selvatici sono sempre più spesso identificati come portatori e potenziali serbatoi della STEC. Lo scopo di questo studio è di determinare la presenza della STEC in 59 campioni fecali di cinghiali selvatici cacciati (Sus scrofa) provenienti da due regioni differenti della Svizzera, il canton Turgovia nella Svizzera settentrionale e il canton Ticino nella Svizzera meridionale, e di caratterizzare gli isolati mediante un sequenziamento del genoma completo. Dopo una fase di arricchimento, i geni che codificano la tossina Shiga (stx) sono stati rilevati mediante PCR in tempo reale nel 41% (intervallo di confidenza al 95% (IC 95%) 0,29 - 0,53) dei campioni, e le STEC sono state successivamente recuperate nel 22% (IC 95% 0,13 - 0,34) degli stessi campioni. Sono stati identificati sette diversi sierotipi e sei diversi tipi di sequenza (ST), con O146:H28 ST738 (n = 4) e O100:H20 ST2514 (n = 4) predominanti. La sottotipizzazione di stx ha identificato isolati con stx1c/stx2b (n = 1), stx2a (n = 1), stx2b (n = 6) e stx2e (n = 6). Nessun isolato conteneva il gene eae, ma tutti contenevano geni di virulenza aggiuntivi, di cui i più comuni che sono stati rilevato sono astA (n = 10), hlyE (n = 9) e hra (n = 9). Le STEC O11:H5, O21:H21 e O146:H28 possedevano fattori di virulenza associati patogeni extra-intestinali di E. coli (ExPEC), e le STEC O100:H20 e O155:H26 possedevano sta1 e/o stb e appartenevano a patotipi ibridi STEC/E. coli enterotossigenici (ETEC).

BACKGROUND: Intestinal infections caused by a shigatoxin-positive Escherichia coli (mostly of the serogroups O26, O45, O103, O111, O121, O145 and especially O157) are a common cause of hemolytic-uremic syndrome. Hemolytic-uremic syndrome was first linked with an E. coli urinary tract infection 40 years ago.
METHODS: We conducted a systematic review of the literature addressing the association between E. coli urinary tract infection and hemolytic-uremic syndrome.
RESULTS: For the final analysis, we retained 23 original reports published since 1979. Five unselected pediatric case series addressed the possible occurrence of hemolytic-uremic syndrome after an acute symptomatic E. coli urinary tract infection among 266 cases and found the mentioned association in 8 (3.0%) cases. We also found 28 individual cases (17 females and 11 males) of hemolytic-uremic syndrome preceded by an E. coli urinary tract infection: 16 children aged from 2 days to 6.0 years and 12 adults aged from 22 to 75 years. Testing for shigatoxin, performed in 19 cases, was positive in 15 cases. E. coli serotyping was performed in 18 cases: testing for serotype O157, O103 and O145 was positive in one, one and two cases, respectively, while testing for serotype O26, O45, O111 and O121 was always negative.
CONCLUSIONS: Hemolytic-uremic syndrome rarely occurs after an acute E. coli urinary tract infection. It affects both children and adults and is mostly caused by germs that are shigatoxin-positive.

Introduction: Hemolytic-uremic syndrome (HUS) is a common cause for intrarenal acute kidney injury in childhood. More than 90% of HUS cases are associated with an infection by Shigatoxin-producing Escherichia coli (STEC) whereas the reminder comprises a heterogeneous group (here classified as Non-STEC-HUS). Renal impairment can persist in patients with HUS. This study presents data from four decades investigating the short- and long-term outcome of HUS in childhood. Materials and Methods: In a retrospective single-center-study clinical and laboratory data of the acute phase and of 1- to 10-year follow-up visits of children with HUS were analyzed. Results: 92 HUS-patients were identified from 1996 to 2014 (STEC-HUS-group: n = 76; Non-STEC-HUS-group: n = 16) and 220 HUS-patients between 1976 and 1995. STEC-HUS was increasingly caused by Non-O157 strains and mortality rate declined over the past decades (1.3 vs. 9.5%). Renal sequelae persisted more often in the group 1976-1995 (39.3%) than in the group 1996-2014 (28.3%), but more than 50% of all patients were lost to follow-up. Conclusion: Although renal outcome has improved over the investigated last decades, patients with HUS still face a high risk of permanent renal damage. These findings underline the importance of a consequent long-term follow-up in HUS-patients.

Shiga toxin-producing Escherichia coli (STEC) is a significant cause of gastrointestinal infection and the haemolytic-uremic syndrome (HUS). STEC outbreaks are commonly associated with food but animal contact is increasingly being implicated in its transmission. We report an outbreak of STEC affecting young infants at a nursery in a rural community (three HUS cases, one definite case, one probable case, three possible cases and five carriers, based on the combination of clinical, epidemiological and laboratory data) identified using culture-based and molecular techniques. The investigation identified repeated animal contact (animal farming and petting) as a likely source of STEC introduction followed by horizontal transmission. Whole genome sequencing (WGS) was used for real-time investigation of the incident and revealed a unique strain of STEC O26:H11 carrying stx2a and intimin. Following a public health intervention, no additional cases have occurred. This is the first STEC outbreak reported from Israel. WGS proved as a useful tool for rapid laboratory characterization and typing of the outbreak strain and informed the public health response at an early stage of this unusual outbreak.

Diarrhea-associated hemolytic uremic syndrome (D+HUS) is a common thrombotic microangiopathy during childhood and early identification of parameters predicting poor outcome could enable timely intervention. This study aims to establish the accuracy of BUN-to-serum creatinine ratio at admission, in addition to other parameters in predicting the clinical course and outcome. Records were searched for children between 1 January 2008 and 1 January 2015 admitted with D+HUS. A complicated course was defined as developing one or more of the following: neurological dysfunction, pancreatitis, cardiac or pulmonary involvement, hemodynamic instability, and hematologic complications while poor outcome was defined by death or development of chronic kidney disease. Thirty-four children were included from which 11 with a complicated disease course/poor outcome. Risk of a complicated course/poor outcome was strongly associated with oliguria (p = 0.000006) and hypertension (p = 0.00003) at presentation. In addition, higher serum creatinine (p = 0.000006) and sLDH (p = 0.02) with lower BUN-to-serum creatinine ratio (p = 0.000007) were significantly associated with development of complications. A BUN-to-sCreatinine ratio ≤40 at admission was a sensitive and highly specific predictor of a complicated disease course/poor outcome.
CONCLUSIONS: A BUN-to-serum Creatinine ratio can accurately identify children with D+HUS at risk for a complicated course and poor outcome. What is Known: • Oliguria is a predictor of poor long-term outcome in D+HUS What is New: • BUN-to-serum Creatinine ratio at admission is an entirely novel and accurate predictor of poor outcome and complicated clinical outcome in D+HUS • Early detection of the high risk group in D+HUS enabling early treatment and adequate monitoring.

The current study was undertaken to characterize Escherichia coli and other Enterobacteriaceae in raw and pasteurized producer-distributor bulk milk (PDBM). A total of 258 samples were collected from purchase points in 8 provinces in South Africa. The samples were tested for antibiotic residues, phosphatase, total aerobic bacteria, coliforms, and E. coli counts. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for identification of isolates. Escherichia coli isolates were characterized for virulence factors, antimicrobial resistance, serotypes, and presumptive E. coli O157:H7. Antibiotic residues and alkaline phosphatase were detected in 2% of both raw and pasteurized PDBM (n=258) and 21% pasteurized PDBM (n=104) samples, respectively. A total of 729 isolates belonging to 21 genera and 59 species were identified. Escherichia coli, Enterobacter cloacae, Klebsiella oxytoca, and Raoultella ornithinolytica were the most abundant species. Spoilage Enterobacteriaceae species exceeded 50% of the total isolates. Escherichia coli was detected and isolated from 36% of the milk samples. Thirty-one E. coli isolates harbored virulence genes stx1/stx2 and 38% (n=121) were presumptive O157:H7. The prevalence of samples with presumptive shigatoxin producing E. coli was 10%. Antimicrobial-resistant E. coli isolates were detected in 70% of the milk samples with 36% of stx1/stx2 positive E. coli showing multi-drug resistance. Information obtained from the study will be used for modeling the public health risk posed by milkborne pathogens in PDBM, which in many cases is consumed by poor and vulnerable members of the population.

BACKGROUND: We report the case of a patient with Shiga toxin (Stx)-associated hemolytic-uremic syndrome (HUS) (STEC-HUS) with a concomitant heterozygous mutation of the gene coding for complement Factor H (CFH).
METHODS: An 18-month-old patient presented with hemolytic anemia and thrombotic microangiopathy in the context of acute gastroenteritis. While the patient did not show kidney or other organ failure, he had persistent hemolysis and complement 3 activation (low C3), leading to the decision to commence immunotherapy with eculizumab (Soliris®) together with transient antibiotic coverage and meningococcal vaccination. Patient outcome was favorable. Diagnostic work-up identified Escherichia coli-associated Type 2 Shiga toxin. Complement analysis showed a heterozygous mutation of the CFH gene (c.2103 G>A, p. Trp701X) resulting in a quantitative CFH defect.
CONCLUSIONS: We report a case of STEC-HUS with a quantitative CFH defect caused by a mutation of the CFH gene. To the best of our knowledge, very few cases of STEC-HUS with complement gene mutation have been reported, but none to date with a CFH mutation. We therefore suggest that complement analyses be performed in patients diagnosed with STEC-HUS in association with low C3 levels, especially in patients presenting with severe or unexpected clinical symptoms.

Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely.

The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22-44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31-17.60) mg/dl, lactate dehydrogenase 1944 (753-2792) U/l, platelets 33 (19-124)/nl and haemoglobin 6.2 (5.2-7.8) g/dl; median (range)], all patients were discharged after 33 (range 19-43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84-2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66-1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a separate pathophysiological mechanism, importantly contributing to Stx2-mediated acute kidney failure. Specifically in young adults, an excellent outcome can be achieved by supportive therapy only.