STEC Infection Research Articles

Impact of non-pharmaceutical interventions during the COVID-19 pandemic on pathogens transmitted via food in the Netherlands.

The COVID-19 pandemic impacted the transmission of many pathogens. The aim was to determine the effect of non-pharmaceutical interventions on the incidence of diseases transmitted via food. Weekly incidence rates for nine foodborne pathogens were collected from national surveillance registries. Weekly pathogen incidence during lockdown weeks of 2020 and 2021 were compared with corresponding weeks in 2015-2019. The same analyses were performed to determine the effect of self-defined expected impact levels of measures (low, intermediate and high). Eight out of 9 diseases showed a significant decrease in case number in 2020, except for listeriosis, which remained unchanged. The largest decrease was observed for rotavirus gastronteritis A (-81%), norovirus gastroenteritis (-78%), hepatitis A (-75%) and shigellosis (-72). In 2021, lower case numbers were observed for 6 out of 9 diseases compared with 2015-2019, with the largest decrease for shigellosis (-5/%) and hepatitis E (-47%). No significant change was observed for listeriosis, STEC infection and rotavirus gastroenteritis. Overall, measures with increased expected impact level did not result in a larger decrease in number of cases, except for Campylobacter, and norovirus and rotavirus gastroenteritis. Disease transmitted via food significantly decreased during the COVID-19 pandemic, with a more pronounced effect during 2020 than 2021.

Differences between males and females in infectious diseases notifications in the EU/EEA, 2012 to 2021.

BackgroundThere are differences between males and females for most diseases both for exposure and course of illness, including outcome. These differences can be related to biological sex or gender i.e. socio-cultural factors that may impact exposure and healthcare access.AimWe aimed to quantify differences between males and females in infectious disease notifications in Europe and identify countries with these differences significantly different from the European Union and European Economic Area (EU/EEA) average.MethodsNotifiable infectious disease surveillance data are reported by EU/EEA countries to ECDC. We retrieved surveillance data for 2012-2021. Using a cut-off median of annual disability-adjusted life years above 1 per 100,000 population, we included 16 infectious diseases. We calculated median male proportion and interquartile range by disease, year, country and age group and used boxplots to identify outliers.ResultsFor campylobacteriosis, acute hepatitis B, Legionnaires' disease, malaria and HIV and AIDS, all countries had male proportion above 50%. Most countries had a male proportion below 50% for pertussis (25/28 countries), STEC infection (21/28 countries) and Chlamydia trachomatis infection (16/24 countries). Chlamydia trachomatis infection and listeriosis showed the greatest dispersion of male proportion across age groups. Most outliers were countries reporting few cases.ConclusionWe observed important differences in male proportion across infectious disease notifications in EU/EEA countries. For some diseases with high male proportions in all countries, such as HIV and hepatitis B, behaviours play a role in disease transmission. Screening offered to specific populations may explain differences across countries for example for C. trachomatis infection.

Impact of Selenium Nanoparticle-Enriched Lactobacilli Feeding Against Escherichia coli O157:H7 Infection of BALB/c Mice.

The effectiveness of selenium nanoparticle (SeNP)-enriched Lactiplantibacillus plantarum and Lactobacillus acidophilus was studied against Shiga toxin-producing Escherichia coli O157:H7 infection on the intestinal fragments and kidney tissue of BALB/c mice. Gut microbiota-targeted bacteria and E. coli O157:H7 counts were obtained by qPCR and PCR. Histology of ileum, colon, and kidney tissues and Stx secretions were analyzed until one-week post-infection. Mice fed with SeNP Lpb. plantarum in the preinfection feeding groups have lower E. coli O157:H7 counts and lower intestinal damage than those in the infected group. The lowest mean fecal probiotic counts were in the L. acidophilus group (7.61 log 10). In pretreatment groups of SeNP L. acidophilus and L. acidophilus, the mean counts of bacteria decreased to 104CFU/g by day 7. The lowest Stx copy number was demonstrated in SeNP Lpb. plantarum feeding groups' day 7 (P < 0.05). Feeding groups with SeNP Lpb. plantarum had significantly higher members of Lactobacilli in their fecal microbiota than the control group on day 7. It was clarified that Se-enriched Lpb. plantarum and L. acidophilus can be useful as a method of preventing STEC infections. The viability of STEC infection exposure to selenium-enriched Lactobacillus spp. was decreased more than for non-Se-enriched Lactobacillus spp.

HUS with mutations in CFH and STEC infection treated with eculizumab in a 4-year-old girl.

Hemolytic uremic syndrome secondary to Shiga-toxin-producing Escherichia coli infection (STEC-HUS) generally shows a favorable outcome. Few cases develop extra-renal complications, since neurological involvement is an important cause of morbidity and mortality. The role of complement in STEC-HUS has been recently highlighted, and the use of eculizumab in severe cases has been communicated. HUS results from environmental and genetic factors, but the simultaneous occurrence of STEC and complement mutations remains undetermined. A pediatric case with severe STEC-HUS carrying CFH mutations, with favorable response to eculizumab is analyzed. STEC-HUS was diagnosed in a 4-year-old girl with classic HUS, including low C3. Peritoneal dialysis was started due to hypertension, oligoanuria, and pleural effusion. She evolved with generalized tonic-clonic seizures and required mechanical ventilation. MRI reported multiple supra- and infratentorial ischemic lesions with laminar/striatal cortical necrosis and leukoencephalopathy. After two eculizumab doses, a significative stabilization in diuresis, blood pressure, creatinine, and C3 was achieved. At the third week, episodes of massive digestive bleeding and a life-threatening condition required a colectomy thus preserving the ileocecal valve. Due to atypical evolution, a genetic study was considered, identifying two heterozygous variants (CFH S1191L/V1197A). STEC-HUS in patients with a genetic predisposition has been previously reported, but the low frequency of occurrence makes it a rare disease. As in the present case, patients with atypical course might benefit from genetic analysis to evaluate early eculizumab initiation and to better understand its phenotype. A higher resolution version of the Graphical abstract is available as Supplementary information.

Effect of chlorine sanitizer on metabolic responses of Escherichia coli biofilms “big six” during cross-contamination from abiotic surface to sponge cake

The effect of chlorine on Escherichia coli biofilm O157:H7 are well established; however, the effect on biofilm adhesion to food as well as the six emerging E. coli serotypes (“big six”) have not been fully understood. Chlorine sanitization with 1-min 100 mg/L was applied against seven pathogenic E. coli (O111, O121:H19, O45:H2, O26:H11, O103:H11, O145, and O157:H7) biofilms on high-density polyethylene (HDPE) and stainless steel (SS) coupons, respectively. Using sponge cake as a food model, the adhesion behavior was evaluated by comparison of bacteria transfer rate before and after treatment. Besides, the metabolic profiles of biofilms were analyzed by nuclear magnetic resonance (NMR) spectrometer. A significant decrease in transfer rate (79% decline on SS and 33% decline on HDPE) was recorded as well as the distinctive pattern between SS and HDPE coupons was also noticed, with a low population (6–7 log CFU/coupon) attached and low survivals (0–3 log CFU/coupon) upon chlorine on SS, while high population (7–8 log CFU/coupon) attached and high survivals (5–7 log CFU/coupon) on HDPE. Moreover, O121:H19 and O26:H11 demonstrated the highest resistance to chlorine with the least metabolic status and pathways affected. O103:H11, O145, and O111 followed similar metabolic patterns on both surfaces. Distinct metabolic patterns were found in O45:H2 and O157:H7, where the former had more affected metabolic status and pathways on SS but less on HDPE, whereas the latter showed an opposite trend. Overall, a potential contamination source of STEC infection in flour products was demonstrated and metabolic changes induced by chlorine were revealed by NMR-based metabolomics, which provides insights to avoid “big six” biofilms contamination in food.

Detection of SHIGA-TOXIN producing E. coli in some retail markets in Egypt using qPCR assay with special reference to serotyping

Background: Shiga toxin-producing Escherichia coli are dangerous foodborne pathogens that represent a severe public health issue worldwide. Raw foods are considered an important source of STEC infection in humans. Objective: In the current study, STEC contamination was investigated in 80 raw foods (chicken, beef, and milk) and water collected from different localities of Greater Cairo using Real-Time PCR. Moreover, the virulence genes of isolates were characterized. Results: STEC was detected in eight samples, (7 beef and 1 chicken), which represent about 10% of the tested samples. Positive beef and chicken samples show the presence of 13 and 2 STEC genes, respectively. Five samples were positive for eaeA (intemin), two samples were positive for stx1 gene and eight samples were positive for stx2 gene. Beef samples reveal the highest incidence of virulence gene stx2 (35%), followed by eaeA (20%), then stx1 (10%). The incidence of STEC was lower in chicken samples and the prevalence of virulence gene was 5% for stx2 and eaeA, respectively. Stx2 gene was the most prevalent subtype identified in beef samples. Serotyping of isolated STEC strains (14) revealed isolation of seven STEC strains belong to O157 serogroup, two strains belong to O111and five strains belong to serogroup O26. Conclusion: The current study concluded that recovery of STEC from raw chicken and beef samples is of important concern.

Neurological involvement in children with hemolytic uremic syndrome

Our objective was to establish the rate of neurological involvement in Shiga toxin-producing Escherichia coli–hemolytic uremic syndrome (STEC-HUS) and describe the clinical presentation, management and outcome. A retrospective chart review of children aged ≤ 16 years with STEC-HUS in Children’s Health Ireland from 2005 to 2018 was conducted. Laboratory confirmation of STEC infection was required for inclusion. Neurological involvement was defined as encephalopathy, focal neurological deficit, and/or seizure activity. Data on clinical presentation, management, and outcome were collected. We identified 240 children with HUS; 202 had confirmed STEC infection. Neurological involvement occurred in 22 (11%). The most common presentation was seizures (73%). In the neurological group, 19 (86%) were treated with plasma exchange and/or eculizumab. Of the 21 surviving children with neurological involvement, 19 (91%) achieved a complete neurological recovery. A higher proportion of children in the neurological group had renal sequelae (27% vs. 12%, P = .031). One patient died from multi-organ failure.Conclusion: We have identified the rate of neurological involvement in a large cohort of children with STEC-HUS as 11%. Neurological involvement in STEC-HUS is associated with good long-term outcome (complete neurological recovery in 91%) and a low case-fatality rate (4.5%) in our cohort.What is Known:• HUS is associated with neurological involvement in up to 30% of cases.• Neurological involvement has been reported as predictor of poor outcome, with associated increased morbidity and mortality.What is New:• The incidence of neurological involvement in STEC-HUS is 11%.• Neurological involvement is associated with predominantly good long-term outcome (90%) and a reduced case-fatality rate (4.5%) compared to older reports.

MO1024CLOSTRIDIUM SEPTICUM INFECTION COMPLICATING HEMOLYTIC UREMIC SYNDROME: A CASE REPORT AND LITERATURE REVIEW

Abstract Background and Aims C.septicum is an anaerobic bacterium that resides in the gastrointestinal tract of herbivores. Its presence in human fecal flora is still debated, being found in only 2.8% of healthy adults. Transmitted by oral-fecal route, it reaches the systemic circulation, causing bacteremia, myonecrosis, bowel necrosis, intracranial abscesses/encephalitis. Shiga-toxin producing E. Coli related hemolytic uremic syndrome (STEC-HUS) is a thrombotic microangiopathy characterized by hemolytic anemia, thrombocytopenia and kidney damage, related to STEC infection. Severe presentation includes gastrointestinal and neurologic involvement. Microangiopathic lesions in the colonic mucosa can facilitate the colonization of systemic circulation by C.septicum, spreading the superinfection. Since the first report in 1988, very few cases of STEC-HUS complicated by C.septicum superinfection have been described in literature and thus the factors predicting clinical outcome are not clear. Method We describe the case of a 5-years-old girl admitted for anemia, AKI, thrombocytopenia and diarrhea. Previous history was unremarkable. STEC-HUS diagnosis was made. Despite prompt conservative treatment, 12h later her clinical condition worsened, showing ESKD needing dialysis, abdominal pain, progressive hyporesponsiveness. The brain CT scan showed pneumocephalus and encephalitis; blood cultures were drawn and broad-spectrum antibiotic therapy was set (Tab.1). Cardiovascular instability prevented surgical treatment of pneumocephalus to be done. The patient died shortly after because of septic shock. Post-mortem stool and blood cultures confirmed STEC infection complicated by C.Septicum. Previous literature on this specific clinical picture has been reviewed and summarized. Results Eleven additional cases (7 males) have been previously described. Mean age of presentation was 2.9 years. A; abdominal symptoms (commonly distention and pain) were reported in all cases, while ESRD was present in 10 cases. Six patients presented fever. Central nervous system presentation as pneumocephalus was associated with poor prognosis, while surgical treatment availability of brain lesions to survival. In one case the infection caused myonecrosis (Tab. 1). The mortality rate was about 60%. In 7 cases, clinical conditions worsened in less than 24h and this was in all cases related to poor outcome. Conclusion C.septicum superinfection complicating STEC-HUS is a rare but fearsome complication to be aware of. Rapid diagnosis and surgical treatment are essential for the successful management of this particular condition.

A fatal case of Shiga toxin-producing Escherichia coli linked to a private drinking water supply.

In May 2017, a fatal case of Shiga toxin-producing &lt;i&gt;Escherichia coli&lt;/i&gt; (STEC) with haemolytic uremic syndrome was investigated by the Victorian Department of Health and Human Services and a local government authority. Investigation revealed the case used rainwater harvested from the roof of their home and stored in tanks as a private drinking water supply, despite the availability of a reticulated supply from the local water authority. &lt;i&gt;Escherichia coli&lt;/I&gt; Stx1 and Stx2 genes were detected in a water sample collected from the private drinking water supply, consistent with those earlier identified in the case’s faecal sample. This case study highlights the potential risks of STEC infection from private drinking water supplies, the importance of proper maintenance of such supplies, and the preferable use of reticulated water supplies when available. It also demonstrated an effective collaboration between local and state government for an environmental public health investigation.

Shiga toxin-producing Escherichia coli in household members of children with hemolytic uremic syndrome.

The objective is to establish the frequency of STEC infections in household contacts of HUS patients. We studied 292 household contacts of 82 HUS patients attended from 2010 to 2018. In HUS cases, diagnostic criteria were (1) isolation and characterization of STEC strains, (2) detection of free fecal Shiga toxin (FFStx), and (3) detection of anti-O serogroup-specific antibodies. Contacts were studied by screening of stx genes by polymerase chain reaction and/or STEC isolation from stool samples. Clonal relation of STEC strains was established by pulsed-field gel electrophoresis (PFGE). Frequencies of HUS patients without STEC isolation with STEC-positive contacts were determined. Serotypes and stx-genotypes in patients and contacts were analyzed. Thirty (36.6%) HUS patients had 36 STEC-positive contacts. Fourteen (38.8%) were children, 20 adults, and 2 dogs. One sibling developed HUS, 6 contacts had gastrointestinal symptoms, and the rest were asymptomatic. In 5 of 30 HUS patients, STEC infection could not be confirmed, and 2 cases were diagnosed only by FFStx detection. Of the remaining 23 HUS patients, 16 had E. coli O157 and 7 E. coli O145 infection. Serotype and/or stx-genotype concordance was established in 19 (83%) of 23 HUS patients and their contacts. Five HUS cases and their contacts studied by PFGE showed macrorestriction patterns with more than 90% similarity. Nearly one third of HUS patients had STEC-positive family contacts, and one third of them were children. Early identification is important to prevent ongoing contamination among family and institutional contacts and to facilitate prompt detection of HUS in STEC-positive contacts.

Predicting Hemolytic Uremic Syndrome and Renal Replacement Therapy in Shiga Toxin-producing Escherichia coli-infected Children.

Shiga toxin-producing Escherichia coli (STEC) infections are leading causes of pediatric acute renal failure. Identifying hemolytic uremic syndrome (HUS) risk factors is needed to guide care. We conducted a multicenter, historical cohort study to identify features associated with development of HUS (primary outcome) and need for renal replacement therapy (RRT) (secondary outcome) in STEC-infected children without HUS at initial presentation. Children aged <18 years who submitted STEC-positive specimens between January 2011 and December 2015 at a participating study institution were eligible. Of 927 STEC-infected children, 41 (4.4%) had HUS at presentation; of the remaining 886, 126 (14.2%) developed HUS. Predictors (all shown as odds ratio [OR] with 95% confidence interval [CI]) of HUS included younger age (0.77 [.69-.85] per year), leukocyte count ≥13.0 × 103/μL (2.54 [1.42-4.54]), higher hematocrit (1.83 [1.21-2.77] per 5% increase) and serum creatinine (10.82 [1.49-78.69] per 1 mg/dL increase), platelet count <250 × 103/μL (1.92 [1.02-3.60]), lower serum sodium (1.12 [1.02-1.23 per 1 mmol/L decrease), and intravenous fluid administration initiated ≥4 days following diarrhea onset (2.50 [1.14-5.46]). A longer interval from diarrhea onset to index visit was associated with reduced HUS risk (OR, 0.70 [95% CI, .54-.90]). RRT predictors (all shown as OR [95% CI]) included female sex (2.27 [1.14-4.50]), younger age (0.83 [.74-.92] per year), lower serum sodium (1.15 [1.04-1.27] per mmol/L decrease), higher leukocyte count ≥13.0 × 103/μL (2.35 [1.17-4.72]) and creatinine (7.75 [1.20-50.16] per 1 mg/dL increase) concentrations, and initial intravenous fluid administration ≥4 days following diarrhea onset (2.71 [1.18-6.21]). The complex nature of STEC infection renders predicting its course a challenge. Risk factors we identified highlight the importance of avoiding dehydration and performing close clinical and laboratory monitoring.

1098. Clinical Features and Outcomes of United States Marine Corps Recruits Hospitalized With Shiga Toxin-Producing Escherichia coli Infection and Hemolytic–Uremic Syndrome

BackgroundShiga toxin-producing Escherichia coli (STEC) is associated with potentially life-threatening dysentery, along with its most feared complication, the hemolytic–uremic syndrome (HUS), occurring in up to 20% of STEC-infected patients. 10–30% of patients may experience chronic renovascular and neurologic sequelae after acute resolution. We describe clinical features and outcomes of a young, male military recruit population hospitalized for STEC infection and HUS in 2017.MethodsBetween October and November 2017, an STEC outbreak occurred at Marine Corps Recruit Depot San Diego (MCRD-SD) affecting 244 recruits, including 30 who required hospitalization. Polymerase chain reaction and pulsed-field gel electrophoresis of stool culture isolates demonstrated stx2-positive E. coli O157:H7. Thirty recruits required hospitalization; the remaining 214 underwent daily clinical evaluation and laboratory testing at MCRD with daily crystalloid volume expansion until the resolution of dysentery.Results50% (15/30) of hospitalized recruits developed HUS and were initially managed with volume expansion until the onset of oliguria. Five recruits with severe HUS required hemodialysis; six required intensive critical care unit (ICU) admission; and three suffered from respiratory failure requiring mechanical ventilation. Average length of hospitalization was 10 days. Patients requiring hemodialysis received an average 7.4 days of renal replacement. Three patients experienced encephalopathy with seizures and were managed with levetiracetam and corticosteroids for Stx-induced cerebral edema. One patient received eculizumab, a terminal complement inhibitor approved for atypical HUS, with resolution of seizures and return to his neurocognitive baseline but with persistent electroencephalographic abnormalities. There were no deaths, and all recruits had recovery of renal function.ConclusionThis case series represents the largest STEC-HUS outbreak affecting a military population. Rates of HUS and mortality were lower than seen in prior outbreaks, in part due to a high level of baseline health and early detection and management of suspect cases. Early volume expansion and close monitoring of cases may have reduced the risk for HUS progression and long-term renal sequelae.Disclosures All authors: No reported disclosures.

678. Outbreak of Shiga Toxin-Producing Escherichia coli Infections at Marine Corps Recruit Depot (MCRD), San Diego and Camp Pendleton, California: October–November, 2017

BackgroundShiga toxin-producing Escherichia coli (STEC) infections are a major cause of foodborne illness and the principal cause of hemolytic-uremic syndrome (HUS). In November 2017, CDC and the US Navy responded to an outbreak of STEC illnesses in military recruits at the Marine Corps Recruit Depot in San Diego (MCRD). We investigated to determine the source of this outbreak and identify prevention and mitigation measures.MethodsIn October 2017, medical staff identified a high number of gastrointestinal (GI) illnesses at MCRD. Recruits with diarrhea submitted stool specimens for culture and/or culture-independent diagnostic testing (CIDT) for GI pathogens. We performed pulsed-field gel electrophoresis (PFGE) on culture isolates. Case-patients were defined as confirmed (PFGE-confirmed STEC infection matching outbreak strains), probable (diagnosis of HUS and/or CIDT evidence of STEC), or suspected (bloody diarrhea). We conducted environmental evaluations of dining facilities, training areas, and barracks. A case–control study was performed using PFGE-confirmed case-patients and platoon-matched controls. We performed product traceback for foods identified as exposure risks by interview or case–control study.ResultsWe identified 64 confirmed, 105 probable, and 91 suspected case-patients. Thirty case-patients required hospitalization and 15 had HUS. Ages ranged from 17 to 28 years (median: 18 years). Poor hygiene practices among recruits and inconsistent cooking temperatures within dining facilities were noted. Forty-three case-patients and 135 controls were interviewed about food, hygiene, and environmental exposures. Consumption of undercooked beef was significantly associated with illness (mOR 2.40, CI 1.04–5.72, P = 0.04). We identified a single ground beef supplier for MCRD, but dining facility records did not document the dates on which specific lots of ground beef were used.ConclusionCase–control analysis and environmental observations suggested undercooked ground beef as a potential source for this outbreak. We recommended the Navy and Marine Corps retain lot information, address food handling concerns, and improve hygiene among recruits.Disclosures All authors: No reported disclosures.

Experimental Application of Organic-Inorganic Hybrid Coatings with Adsorbed Bacteriophages for Reducing the Risk of STEC Infections.

A new approach to prevention of STEC infection is based on the synergic effect of combined bactericidal activity of bacteriophages and organic-inorganic hybrid coating of metals. The coatings are characterized by superhydrophilic or superhydrophobic properties and multimodal granularity with the texture incorporating metal oxide nanoparticles and bacteriophages. Superhydrophilic surfaces are characterized by significantly higher bactericidal activity than superhydrophobic ones. The cytotoxicity of superhydrophobic surfaces can be increased due to antibacterial activity of bacteriophages combined with the superhydrophobic characteristics of the materials.

Emergency Department Management of Stec Infection: a Multi-national, Multi-specialty Survey

Emergency Department Management of Stec Infection: a Multi-national, Multi-specialty Survey

Shiga Toxin (Verotoxin)-producing Escherichia coli and Foodborne Disease: A Review.

Shiga toxin (verotoxin)-producing Escherichia coli (STEC) is an important cause of foodborne disease. Since outcomes of the infections with STEC have a broad range of manifestation from asymptomatic infection or mild intestinal discomfort, to bloody diarrhea, hemolytic uremic syndrome (HUS), end-stage renal disease (ESRD), and death, the disease is a serious burden in public health and classified as a notifiable infectious disease in many countries. Cattle and other ruminants are considered to be the major reservoirs of STEC though isolation of STEC from other animals have been reported. Hence, the source of contamination extends to a wide range of foods, not only beef products but also fresh produce, water, and environment contaminated by excretes from the animals, mainly cattle. A low- infectious dose of STEC makes the disease relatively contagious, and causes outbreaks with unknown contamination sources and, therefore, as a preventive measure against STEC infection, it is important to obtain characteristics of prevailing STEC isolates in the region through robust surveillance. Analysis of the isolates by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA) could help finding unrecognized foodborne outbreaks due to consumption of respective contaminated sources. However, though the results of molecular analysis of the isolates could indicate linkage of sporadic cases of STEC infection, it is hardly concluded that the cases are related via contaminated food source if it were not for epidemiological information. Therefore, it is essential to combine the results of strain analysis and epidemiological investigation rapidly to detect rapidly foodborne outbreaks caused by bacteria. This article reviews STEC infection as foodborne disease and further discusses key characteristics of STEC including pathogenesis, clinical manifestation, prevention and control of STEC infection. We also present the recent situation of the disease in Japan based on the surveillance of STEC infection.

Effectiveness of F18+ Fimbrial Antigens Released by a Novel Autolyzed Salmonella Expression System as a Vaccine Candidate against Lethal F18+ STEC Infection.

Porcine edema disease (ED) caused by Shiga toxin 2e producing Escherichia coli expressing F18ab+ fimbriae (F18ab+STEC) frequently occurs in post-weaned piglets, resulting in a significant economic loss in swine industries worldwide. In the present study, we proposed an efficient prevention scheme against ED in which the attenuated Salmonella Typhimurium inactivated by the E-mediated cell lysis to deliver target antigens, FedF and FedA, which function in fimbrial-mediated adhesion and as a major subunit of F18ab+fimbriae, respectively. The co-expression of FedA and FedF protein with outer membrane protein A signal peptide was confirmed in the resultant strains JOL1460 and JOL1464 by immunoblot analysis. Immunization with the candidate strains in mice led to the significant generation of immunoglobulin (Ig) G, specific to both antigens and secretory IgA specific to FedF (P < 0.05). The titers of IgG isotypes, IgG1 and IgG2a, used as markers for T-helpers (Th)-2 and Th-1lymphocytes, respectively, also significantly increased in the immunized group (P < 0.05). The increase in CD3+CD4+ T lymphocyte subpopulation and in vitro proliferative activity was observed in in vivo stimulated splenocytes, which indicated the immunostimulatory effect of the candidate strains. Moreover, the immunized mice were completely protected from a lethal challenge against wild-type F18+STEC whereas 28% of mice died in the non-immunized group. This study demonstrated that the inactivated Salmonella system could efficiently release FedF and FedA and induce robust immune responses specific to the target antigens, which is sufficient to protect the mice from the lethal challenge.

Transmission pathways for sporadic Shiga-toxin producing E. coli infections: A systematic review and meta-analysis.

Shiga-toxin E. coli infections remain a public health concern because of the severity of the gastrointestinal illness and associated complications. Transmission pathways are typically elucidated from outbreaks, with foodborne transmission the primary source. However, most STEC cases are sporadic. This systematic review aimed to identify the most common pathways for sporadic STEC transmission and quantify their importance. We systematically reviewed epidemiological studies of sporadic (non-outbreak) STEC cases that investigated potential risk factors. Searches were run in Medline, EMBASE, and Scopus. Included studies needed to confirm STEC infection and investigate ≥20 cases. 31 studies were included, of which 25 were case-control or case-case studies. 62.5% found consumption of undercooked/raw meat associated with STEC infection while 70.4% found contact with animals or their environment a risk factor. Random-effects meta-analysis provided pooled odds ratios and population attributable fraction (PAF). The PAF was 19% for undercooked/raw meat, followed by person to person transmission at 15%. Contact with animals and visiting farm environments had PAFs of 14% and 12% respectively. Out of potential sources for STEC exposure, undercooked meat and contact with animals and their environment were the most frequently found transmission routes. Decreasing the chances of acquiring the bacteria by these methods would additionally cut down on the other major transmission route, person-to-person spread.

Protection against Shiga-Toxigenic Escherichia coli by Non-Genetically Modified Organism Receptor Mimic Bacterial Ghosts.

Shiga-toxigenic Escherichia coli (STEC) causes severe gastrointestinal infections in humans that may lead to life-threatening systemic sequelae, such as the hemolytic uremic syndrome (HUS). Rapid diagnosis of STEC infection early in the course of disease opens a window of opportunity for therapeutic intervention, for example, by administration of agents that neutralize Shiga toxin (Stx) in the gut lumen. We previously developed a recombinant bacterium that expresses a mimic of the Stx receptor globotriaosyl ceramide (Gb3) on its surface through modification of the lipopolysaccharide (A. W. Paton, R. Morona, and J. C. Paton, Nat Med 6:265-270, 2000, http://dx.doi.org/10.1038/73111). This construct was highly efficacious in vivo, protecting mice from otherwise fatal STEC disease, but the fact that it is a genetically modified organism (GMO) has been a barrier to clinical development. In the present study, we have overcome this issue by development of Gb3 receptor mimic bacterial ghosts (BGs) that are not classified as GMOs. Gb3-BGs neutralized Stx1 and Stx2 in vitro with high efficiency, whereas alternative Gb3-expressing non-GMO subbacterial particles (minicells and outer membrane blebs) were ineffective. Gb3-BGs were highly efficacious in a murine model of STEC disease. All mice (10/10) treated with Gb3-BGs survived challenge with a highly virulent O113:H21 STEC strain and showed no pathological signs of renal injury. In contrast, 6/10 mice treated with control BGs succumbed to STEC challenge, and survivors exhibited significant weight loss, neutrophilia, and histopathological evidence of renal damage. Thus, Gb3-BGs offer a non-GMO approach to treatment of STEC infection in humans, particularly in an outbreak setting.

The epidemiology, microbiology and clinical impact of Shiga toxin-producing Escherichia coli in England, 2009-2012.

Between 1 January 2009 and 31 December 2012 in England, a total of 3717 cases were reported with evidence of Shiga toxin-producing E. coli (STEC) infection, and the crude incidence of STEC infection was 1·80/100 000 person-years. Incidence was highest in children aged 1-4 years (7·63/100 000 person-years). Females had a higher incidence of STEC than males [rate ratio (RR) 1·24, P < 0·001], and white ethnic groups had a higher incidence than non-white ethnic groups (RR 1·43, P < 0·001). Progression to haemolytic uraemic syndrome (HUS) was more frequent in females and children. Non-O157 STEC strains were associated with higher hospitalization and HUS rates than O157 STEC strains. In STEC O157 cases, phage type (PT) 21/28, predominantly indigenously acquired, was also associated with more severe disease than other PTs, as were strains encoding stx2 genes. Incidence of STEC was over four times higher in people residing in rural areas than urban areas (RR 4·39, P < 0·001). Exposure to livestock and/or their faeces was reported twice as often in cases living in rural areas than urban areas (P < 0·001). Environmental/animal contact remains an important risk factor for STEC transmission and is a significant driver in the burden of sporadic STEC infection. The most commonly detected STEC serogroup in England was O157. However, a bias in testing methods results in an unquantifiable under-ascertainment of non-O157 STEC infections. Implementation of PCR-based diagnostic methods designed to detect all STEC, to address this diagnostic deficit, is therefore important.