One problem, multiple potential targets: Where are we now in the development of small molecule inhibitors against Shiga toxin?

Shiga toxin-producing Escherichia coli (STEC) are a group of enteric pathogens which carry phage-encoded Shiga toxins (Stx). STEC infections begin with severe abdominal pain and non-bloody diarrhoea, which can progress to bloody diarrhoea after approximately 4-days post-infection. In high-risk groups such as children and the elderly, patients may develop haemolytic uremic syndrome (HUS). HUS is characterised by microangiopathic haemolytic anaemia, thrombocytopenia, and in severe disease acute renal failure. Traditional antibiotics have been linked with increased toxin production due to the activation of recA-mediated bacterial stress response, resulting in poorer patient outcomes. Therefore, treatment relies on supportive therapies. Antivirulence strategies have been explored as an alternative treatment for bacterial infections and blockers of virulence factors such as the Type III Secretion System. Recent improvements in the mechanistic understanding of the Stx pathway have led to the design of inhibitors to disrupt the pathway, leading to toxin-mediated ribosome damage. However, compounds have yet to progress beyond Phase III clinical trials successfully. This review explores the progress in developing small molecule inhibitors by collating lead compounds derived from in-silico and experimental approaches.

Seed-specific expression of porcine verotoxigenic Escherichia coli antigens in tobacco plants as a potential model of edible vaccines.

Vaccines can reduce the use of antibiotics by preventing specific infective diseases in pigs. Plant-based edible vaccines are particularly attractive because, upon oral ingestion via feed, they can elicit the local immune system against a foreign disease-causing organism. The aim of this study was to engineer two different independent lines of tobacco plants for the seed-specific expression of immunogenic proteins of VTEC as a model of an edible vaccine. For each antigen, fifty Nicotiana tabacum L. cv Xanthi leaf disks were transformed by agroinfection for the seed-specific expression of the structural parts of the fimbrial subunit FedF of F18 and the B-subunit of Vt2e genes. The synthetic genes, optimized by the codon adaptation index for their expression in tobacco, were inserted into expression cassettes under the control of ß-conglycinin promoter. Regenerated tobacco plants (T0) were characterized by molecular and immunoenzymatic techniques. Our results showed that both FedF and Vt2eB genes were integrated into tobacco genome efficiently (> 80%) and they are also maintained in the second generation (T1). Western blotting analyses carried out on the positive producing lines, showed the tissue-specific expression in seeds and the temporal protein accumulation in the mid-late maturation phases. The enzyme-linked immunosorbent assay showed seed expression levels of 0.09 to 0.29% (from 138 to 444 µg/g of seeds) and 0.21 to 0.43% (from 321 to 658 µg/g of seeds) of total soluble protein for the FedF and Vt2eB antigens, respectively. This study confirmed the seed-specific expression of the selected antigens in plant seeds. The expression level is suitable for seed-based edible vaccination systems, which could represent a cost-effective way to prevent VTEC infection. Our findings encourage further in vivo studies focused on the activation of the local immune response.

Haemolytic uraemic syndrome in children England, Wales, Northern Ireland, and Ireland: A prospective cohort study.

Haemolytic uraemic syndrome (HUS) caused by infection with Shiga toxin-producing Escherichia coli (STEC) is a relatively rare but potentially fatal multisystem syndrome clinically characterised by acute kidney injury. This study aimed to provide robust estimates of paediatric HUS incidence in England, Wales, Northern Ireland, and the Republic of Ireland by using data linkage and case reconciliation with existing surveillance systems, and to describe the characteristics of the condition. Between 2011 and 2014, 288 HUS patients were included in the study, of which 256 (89.5%) were diagnosed as typical HUS. The crude incidence of paediatric typical HUS was 0.78 per 100,000 person-years, although this varied by country, age, gender, and ethnicity. The majority of typical HUS cases were 1 to 4 years old (53.7%) and female (54.0%). Clinical symptoms included diarrhoea (96.5%) and/or bloody diarrhoea (71.9%), abdominal pain (68.4%), and fever (41.4%). Where STEC was isolated (59.3%), 92.8% of strains were STEC O157 and 7.2% were STEC O26. Comparison of the HUS case ascertainment to existing STEC surveillance data indicated an additional 166 HUS cases were captured during this study, highlighting the limitations of the current surveillance system for STEC for monitoring the clinical burden of STEC and capturing HUS cases.

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 104 CFU/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.

Assessment of Cell Cycle and Induction of Apoptosis by Shiga-like Toxin Produced by Escherichia coli O157:H7 in T47D Breast Cancer Cells Using Flow Cytometry.

BACKGROUND: The low general toxicity against tumors expressing globotriaosylceramide (Gb3) and Shiga-like toxins produced by E. coli have been proposed as an anti-cancer therapy because of their specific target. This study aimed to determine the potency of the local strains of E. coli O157:H7 isolated from humans and cattle as a new breast cancer therapy by analyzing the cell cycle's inhibition and apoptosis induction. MATERIAL AND METHODS: Approximately 10 cultured T47D cells were subjected to Shiga-like toxin produced by four local isolates of E. coli O157:H7, including KL-48 (2) from humans, and SM-25 (1), SM-7 (1), DS-21 (4) from cattle. Using ATCC 43894 as a control, the treatment was observed for 24 h by two replications. In addition, a FITC-Annexin V and PI assay were used to observe apoptosis and necrosis effect, as well as to analyze the cell cycle using propidium iodide (PI) staining. RESULTS: The results showed the toxicity effect of Shiga in the human T47 D cells line. The viability of the cells is subjected to Shiga-like toxins produced by KL-48 (2), SM7 (1), ATCC 43894, SM-25 (1), and DS-21 (4) isolates decreased with 15.20, 16.36, 22.17,  22.64, and 33.86%, in contrary to control of 94.36%. These were supported by the cells entering the late apoptosis of the cell cycle through each isolate with 67.66, 62.60, 63.68, 63.90, and 54.74%, and a control of 0.01%. Also, the necrosis cell for each treatment of 12.73, 19.3, 10.84, 10.53, and 4.86% was higher than the control of 5.51%. These were confirmed by the higher percentage of the cells treated with toxins of KL-48 (2), SM7(1), ATCC 43894, SM-25 (1), and DS-21 (4), which entered G0-G1 of the cell cycle phase with 66.41, 63.37, 61.52, 55.36, and 47.28%, respectively, than control of 40.69%. Additionally, the toxicity effect was supported by an increase in the cells entering the S and the G2-M phase of the cycle for each treatment. CONCLUSION: It is concluded that the Shiga-like toxin produced by E. coli O157:H7 local isolates can be developed as a drug against breast cancer based on its effect to arrest induction of the cell cycle and inducing apoptosis.

Interactions between the Re-Emerging Pathogen Corynebacterium diphtheriae and Host Cells.

Corynebacterium diphtheriae, the etiological agent of diphtheria, is a re-emerging pathogen, responsible for several thousand deaths per year. In addition to diphtheria, systemic infections, often by non-toxigenic strains, are increasingly observed. This indicates that besides the well-studied and highly potent diphtheria toxin, various other virulence factors may influence the progression of the infection. This review focuses on the known components of C. diphtheriae responsible for adhesion, invasion, inflammation, and cell death, as well as on the cellular signaling pathways activated upon infection.

Evidence of on-going transmission of Shiga toxin-producing Escherichia coli O157:H7 following a foodborne outbreak.

In August 2019, public health surveillance systems in Scotland and England identified seven, geographically dispersed cases infected with the same strain (defined as isolates that fell within the same five single nucleotide polymorphism single linage cluster) of Shiga toxin-producing Escherichia coli O157:H7. Epidemiological analysis of enhanced surveillance questionnaire data identified handling raw beef and shopping from the same national retailer (retailer A) as the common exposure. Concurrently, a microbiological survey of minced beef at retail identified the same strain in a sample of minced beef sold by retailer A, providing microbiological evidence of the link. Between September and November 2019, a further four primary and two secondary cases infected with the same strain were identified; two cases developed haemolytic uraemic syndrome. None of the four primary cases reported consumption of beef from retailer A and the transmission route of these subsequent cases was not identified, although all four primary cases visited the same petting farm. Generally, outbreaks of STEC O157:H7 in the UK appear to be distinct, short-lived events; however, on-going transmission linked to contaminated food, animals or environmental exposures and person-to-person contact do occur. Although outbreaks of STEC caused by contaminated fresh produce are increasingly common, undercooked meat products remain a risk of infection.

Complete genome sequence of Escherichia coli K_EC180, a bacterium producing shiga-like toxin isolated from swine feces.

Escherichia coli normally colonizes the lower intestine of animals and humans, but some serotypes are foodborne pathogens. The Escherichia coli K_EC180 was isolated from swine feces that were collected from a weaner pig. In this genome announcement, E. coli K_EC180 was sequenced using PacBio RS II and Illumina NextSeq 500 platforms. The complete chromosome of E. coli K_EC180 is composed of one circular chromosome (5,017,281 bp) with 50.4% of guanine + cytosine (G + C) content, 4,935 of coding sequence (CDS), 88 of tRNA, and 22 of rRNA genes. The complete genome of E. coli K_EC180 contains the toxin genes such as shiga-like toxins (stxA and stxB).

Epidemiological investigation of recurrent outbreaks of haemolytic uraemic syndrome caused by Shiga toxin-producing Escherichia coli serotype O55:H7 in England, 2014-2018.

Recurrent outbreaks of haemolytic uraemic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC) serotype O55:H7 occurred in England between 2014 and 2018. We reviewed the epidemiological evidence to identify potential source(s) and transmission routes of the pathogen, and to assess the on-going risk to public health. Over the 5-year period, there were 43 confirmed and three probable cases of STEC O55:H7. The median age of cases was 4 years old (range 6 months to 69 years old) and over half of all cases were female (28/46, 61%). There were 36/46 (78.3%) symptomatic cases, and over half of all cases developed HUS (25/46, 54%), including two fatal cases. No common food or environmental exposures were identified, although the majority of cases lived in rural or semi-rural environments and reported contact with both wild and domestic animals. This investigation informed policy on the clinical and public health management of HUS caused by STEC other than serotype O157:H7 (non-O157 STEC) in England, including comprehensive testing of all household contacts and household pets and more widespread use of polymerase chain reaction assays for the rapid diagnosis of STEC-HUS.

Potent in vitro antitumor activity of B-subunit of Shiga toxin conjugated to the diphtheria toxin against breast cancer.

Immunotoxins are protein-based drugs consist of a target-specific binding domain and a cytotoxic domain to eliminate target cells. Such compounds are potentially therapeutic to combat diseases such as cancer. Generally, the B-subunit of Shiga toxin (STXB) receptor, globotriaosylceramide (Gb3), is expressed in high amounts on a number of human tumors cancer cells. In this study, we evaluated a new antitumor candidate called DT389-STXB chimeric protein, which genetically fused the DT to B-subunit of Shiga-like toxin (STXB). First a chimeric protein, encoding DT389-STXB was synthesized. The optimized chimeric protein expressed in E.coli BL21 (DE3) and confirmed by anti-His Western blot analysis. T47D, SKBR3, 4T1 and MCF7 cell lines were treated separately with purified DT389-STXB recombinant protein and functional activity of DT389-STXB was analyzed by the cell enzyme-linked immunosorbentassay (ELISA), MTT, ICC, Western blot and apoptosis tests. The results indicated that the recombinant DT389-STXB fusion protein with a molecular weight of 53 kDa was successfully expressed in E.coli BL21 (DE3) and the anti-His western-blot was used to confirm the presence of the protein. The DT389-STXB fusion protein attached to T47D, SKBR3 and 4T1 cell lines with the proper affinity and induced dose-dependent cytotoxicity against GB3-expressing cancer cells in vitro. Our results showed that DT389-STXB fusion protein may be a promising candidate for antitumor therapy agent against breast cancer; however, further studies are required to explore its efficacy in vivo for therapeutic applications.

Shiga-Like Toxin Produced by Local Isolates of Escherichia coli O157:H7 Induces Apoptosis of the T47 Breast Cancer Cell Line.

PURPOSE: It has been suggested that Shiga-like toxins produced by Escherichia coli O157:H7 could be used as novel therapeutic agents against malignant tumors. In addition, the antitumor potency of local isolates from Indonesia, which are known to be less toxic than the control isolate ATCC 43894, has not yet been tested. The study aimed to analyze local strains of E. coli O157:H7 as a proapoptosis agent on the T47 breast cancer cell line. METHODS: As many as 30 culture cells of T47D breast cancer cell line were subjected to purified extracts of Shiga-like toxin originating from 5 local isolates of E. coli O157:H7: KL-48(2), SM-25(1), SM-7(1), DS-21(4), and 1 isolate ATCC 43894 which was used as a control. Toxin production of each isolate was detected using a sandwich enzyme-linked immunosorbent assay, and the treatment of cell lines was observed for 24 hours, with 2 replications; 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide tests and acridine orange/ethidium bromide double staining assays were used for detection and analyses of apoptosis. RESULTS: The study showed 2 local strains of E. coli O157:H7 (codes KL-48(2) and SM-25(1)) had toxins positive at titer 5 and 10 µg/100 µL. These titers were lower than the control isolate ATCC 43894, but they had a necrosis effect higher (P < .05), ie, 80.3%, than control isolate, ie, 63.3%. Other local strain SM-25(1) also had a good necrosis effect. It has a nondifferent necrosis effect (P > .05) with the control isolate ATCC 43894, ie, 13.0% from 13.3%. CONCLUSION: This study concludes that the Shiga toxin produced by E. coli O157:H7 local isolate (Indonesia) has potential as a proapoptotic and/or necrotic agent for treating T47 breast cancer cell lines, as effectively as ATCC 43894 control isolates.

Point-of-care multiplex-PCR enables germ identification in haemolytic uremic syndrome 94 h earlier than stool culture.

Haemolytic uremic syndrome often affects children causing a relevant morbidity and mortality. We compared the time to diagnosis by multiplex-PCR and stool culture in 15 children from two centres. Multiplex-PCR accelerated the time to diagnosis by 94 (95% confidence interval, 80-119; P = 0.0007) hours. Multiplex-PCR offers a time advantage of stool culture that may aid in earlier identification of outbreak clusters.

Expression of a Shiga-Like Toxin during Plastic Colonization by Two Multidrug-Resistant Bacteria, Aeromonas hydrophila RIT668 and Citrobacter freundii RIT669, Isolated from Endangered Turtles (Clemmys guttata).

Aeromonas hydrophila RIT668 and Citrobacter freundii RIT669 were isolated from endangered spotted turtles (Clemmys guttata). Whole-genome sequencing, annotation and phylogenetic analyses of the genomes revealed that the closest relative of RIT668 is A. hydrophila ATCC 7966 and Citrobacter portucalensis A60 for RIT669. Resistome analysis showed that A. hydrophila and C. freundii harbor six and 19 different antibiotic resistance genes, respectively. Both bacteria colonize polyethylene and polypropylene, which are common plastics, found in the environment and are used to fabricate medical devices. The expression of six biofilm-related genes-biofilm peroxide resistance protein (bsmA), biofilm formation regulatory protein subunit R (bssR), biofilm formation regulatory protein subunit S (bssS), biofilm formation regulator (hmsP), toxin-antitoxin biofilm protein (tabA) and transcriptional activator of curli operon (csgD)-and two virulence factors-Vi antigen-related gene (viaB) and Shiga-like toxin (slt-II)-was investigated by RT-PCR. A. hydrophila displayed a >2-fold increase in slt-II expression in cells adhering to both polymers, C. freundii adhering on polyethylene displayed a >2-fold, and on polypropylene a >6-fold upregulation of slt-II. Thus, the two new isolates are potential pathogens owing to their drug resistance, surface colonization and upregulation of a slt-II-type diarrheal toxin on polymer surfaces.

Investigation into a national outbreak of STEC O157:H7 associated with frozen beef burgers, UK, 2017.

In November 2017, Public Health England identified an outbreak of Shiga toxin-producing Escherichia coli O157:H7 in England where whole genome sequencing results indicated cases were likely to be linked to a common source, and began investigations. Hypothesis generation included a review of enhanced surveillance data, a case-case study and trawling interviews. The hypothesis of interest was tested through the administration of focussed questionnaires and review of shopping history using loyalty card data. Twelve outbreak cases were detected, eight were hospitalised and four developed haemolytic uraemic syndrome. Frozen beef burgers supplied by a national retailer were identified as the vehicle of the outbreak. Testing of two left-over burger samples obtained from the freezers of two separate (unlinked) cases and a retained sample from the production premises were tested and found to be positive for the outbreak strain. A voluntary recall of the burgers was implemented by the retailer. Investigations at the production premises identified no contraventions of food safety legislation. Cooking guidance on the product packaging was deemed to be adequate and interviews with the cases/carers who prepared the burgers revealed no deficiencies in cooking practices at home. Given the long-shelf life of frozen burgers, the product recall likely prevented more cases.

Fallow Deer (Dama dama) as a Reservoir of Shiga Toxin-Producing Escherichia coli (STEC).

Shiga toxin-producing Escherichia (E.) coli (STEC) are responsible for the outbreaks of serious diseases in humans. Only a few reports on fallow deer as a reservoir of foodborne pathogens have been published to date. The purpose of this study was to determine the occurrence of STEC strains in the fallow deer population in Poland. In all, 94 fallow deer swabs were tested. Polymerase chain reaction (PCR) was performed to detect the virulence profile of stx1, stx2 and eae or aggR genes, to identify the subtypes of stx1 and stx2 genes and to perform O and H serotyping. STEC and attaching and effacing (AE)-STEC were identified in 13 isolates (13.83%). The most hazardous virulence profile was detected in three strains, namely stx2d serotype O103:HNM, eae/stx1a serotype O26:HNM and eae/stx1a serotype O157:H7. The predominant stx gene was stx2, which was identified in 76.92% of isolates. E. coli O157 was detected in 4/94 (4.26%). Other E. coli serogroups, O26, O103, O111 and O145, were identified in 14/94 fallow deer (14.89%). The present findings suggest that fallow deer are carriers of STEC/AE-STEC that are potentially pathogenic to humans.

Designing and Analyzing the Structure of DT-STXB Fusion Protein as an Anti-tumor Agent: An in Silico Approach.

BACKGROUND & OBJECTIVE: A main contest in chemotherapy is to obtain regulator above the biodistribution of cytotoxic drugs. The utmost promising strategy comprises of drugs coupled with a tumor-targeting bearer that results in wide cytotoxic activity and particular delivery. The B-subunit of Shiga toxin (STxB) is nontoxic and possesses low immunogenicity that exactly binds to the globotriaosylceramide (Gb3/CD77). Gb3/CD77 extremely expresses on a number of human tumors such as pancreatic, colon, and breast cancer and acts as a functional receptor for Shiga toxin (STx). Then, this toxin can be applied to target Gb3-positive human tumors. In this study, we evaluated DT390-STXB chimeric protein as a new anti-tumor candidate via genetically fusing the DT390 fragment of DT538 (Native diphtheria toxin) to STxB. METHODS: This study intended to investigate the DT390- STxB fusion protein structure in silico. Considering the Escherichia coli codon usage, the genomic construct was designed. The properties and the structure of the protein were determined by an in silico technique. The mRNA structure and the physicochemical characteristics, construction, and the stability of the designed chimeric protein were analyzed using computational and bioinformatics tools and servers. Hence, the GOR4 and I-TASSER online web servers were used to predict the secondary and tertiary structures of the designed protein. RESULTS: The results demonstrated that codon adaptation index (CAI) of dt390-stxB chimeric gene raised from 0.6 in the wild type to 0.9 in the chimeric optimized gene. The mfold data revealed that the dt390-stxB mRNA was completely stable to be translated effectively in the novel host. The normal activity of the fusion protein determined by considering the secondary and tertiary structure of each construct. Energy calculation data indicated that the thermodynamic ensemble for mRNA structure was -427.40 kJ/mol. The stability index (SI) of DT390-STxB was 36.95, which is quite appropriate to preserve the stability of the construct. Ultimately, the DT390-STxB was classified as a steady fusion protein according to the Ramachandran plot. CONCLUSION: Our results showed that DT390-STXB was a stable chimeric protein and it can be recruited as a candidate of novel anti-tumor agents for the development of breast cancer treatment.

Development of an Arginine Anchored Nanoglobule with Retrograde Trafficking Inhibitor (Retro-2) for the Treatment of an Enterohemorrhagic Escherichia coli Outbreak.

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) or Shiga toxin-producing E. coli (STEC) is known to cause sporadic and epidemic gastrointestinal infections with several incidences of outbreaks. Antibiotic-based therapy further worsens the condition by facilitating the release of Shiga toxins (Stx) and lipopolysaccharides (LPS). Hence, there is an urgent need to develop an antibiotic-free, safe, and effective therapeutic intervention for the treatment of EHEC infections. We proposed a novel therapeutic strategy to address this clinical problem-kill, capture, and inhibit. We aimed to formulate and characterize lauroyl arginate ethyl ester (LAE) and Retro-2 loaded self-nano emulsifying drug delivery systems (SNEDDS). Retro-2 is a recently developed novel class of molecule, which can selectively inhibit retrograde transport of Stx. In this paper, we first carried out preformulation studies of Retro-2, followed by the development of SNEDDS forming arginine anchored nanoglobules (AR-NG), characterization of LPS binding to AR-NG, and finally evaluation of activity against EHEC. Retro-2 showed extremely poor solubility at all gastrointestinal pH values, susceptibility to acidic environments, and good permeability. The positively charged AR-NG spontaneously formed a globule size of 102.8 ± 1.9 nm with a surface charge of +52.15 ± 3 mV and increased the solubility of Retro-2. Further, binding and aggregation of LPS and AR-NG were confirmed by particle size, polydispersity index, zeta potential, fluorescent intensity, turbidity analysis, and a limulus amebocyte lysate (LAL) test. Additionally, a significant reduction in LPS induced TNF-α was observed in AR-NG treated macrophages. Thus, in this paper, we demonstrate a very promising and innovative therapeutic approach based on the "kill (E. Coli), capture (released LPS), and inhibit (transport of Stx)" concept.

Influence of socio-economic status on Shiga toxin-producing Escherichia coli (STEC) infection incidence, risk factors and clinical features.

Shiga toxin-producing Escherichia coli (STEC) infection can cause serious illness including haemolytic uraemic syndrome. The role of socio-economic status (SES) in differential clinical presentation and exposure to potential risk factors amongst STEC cases has not previously been reported in England. We conducted an observational study using a dataset of all STEC cases identified in England, 2010-2015. Odds ratios for clinical characteristics of cases and foodborne, waterborne and environmental risk factors were estimated using logistic regression, stratified by SES, adjusting for baseline demographic factors. Incidence was higher in the highest SES group compared to the lowest (RR 1.54, 95% CI 1.19-2.00). Odds of Accident and Emergency attendance (OR 1.35, 95% CI 1.10-1.75) and hospitalisation (OR 1.71, 95% CI 1.36-2.15) because of illness were higher in the most disadvantaged compared to the least, suggesting potential lower ascertainment of milder cases or delayed care-seeking behaviour in disadvantaged groups. Advantaged individuals were significantly more likely to report salad/fruit/vegetable/herb consumption (OR 1.59, 95% CI 1.16-2.17), non-UK or UK travel (OR 1.76, 95% CI 1.40-2.27; OR 1.85, 95% CI 1.35-2.56) and environmental exposures (walking in a paddock, OR 1.82, 95% CI 1.22-2.70; soil contact, OR 1.52, 95% CI 2.13-1.09) suggesting other unmeasured risks, such as person-to-person transmission, could be more important in the most disadvantaged group.

Associating sporadic, foodborne illness caused by Shiga toxin-producing Escherichia coli with specific foods: a systematic review and meta-analysis of case-control studies.

Shiga toxin-producing Escherichia coli (STEC) infections are a significant public health issue, with foodborne transmission causing >1 million illnesses worldwide each year. We conducted a systematic review and meta-analysis (PROSPERO registry # CRD42017074239), to determine the relative association of different food types with sporadic illnesses caused by STEC. Searches were conducted from 01 August to 30 September 2017, using bibliographic and grey literature databases, websites and expert consultation. We identified 22 case-control studies of sporadic STEC infection in humans, from 10 countries within four World Health Organization subregions, from 1985 to 2012. We extracted data from 21 studies, for 237 individual measures in 11 food categories and across three status types (raw or undercooked, not raw and unknown). Beef was the most significant food item associated with STEC illness in the Americas and Europe, but in the Western Pacific region, chicken was most significant. These findings were not significantly moderated by the raw or cooked status of the food item, nor the publication year of the study. Data from the African, South-East Asian and Eastern Mediterranean subregions were lacking and it is unclear whether our results are relevant to these regions.

Analysis of individual patient data to describe the incubation period distribution of Shiga-toxin producing Escherichia coli.

Shiga-toxin producing Escherichia coli (STEC) is a pathogen that can cause bloody diarrhoea and severe complications. Cases occur sporadically but outbreaks are also common. Understanding the incubation period distribution and factors influencing it will help in the investigation of exposures and consequent disease control. We extracted individual patient data for STEC cases associated with outbreaks with a known source of exposure in England and Wales. The incubation period was derived and cases were described according to patient and outbreak characteristics. We tested for heterogeneity in reported incubation period between outbreaks and described the pattern of heterogeneity. We employed a multi-level regression model to examine the relationship between patient characteristics such as age, gender and reported symptoms; and outbreak characteristics such as mode of transmission with the incubation period. A total of 205 cases from 41 outbreaks were included in the study, of which 64 cases (31%) were from a single outbreak. The median incubation period was 4 days. Cases reporting bloody diarrhoea reported shorter incubation periods compared with cases without bloody diarrhoea, and likewise, cases aged between 40 and 59 years reported shorter incubation period compared with other age groups. It is recommended that public health officials consider the characteristics of cases involved in an outbreak in order to inform the outbreak investigation and the period of exposure to be investigated.