Enterohemorrhagic Escherichia Coli Outbreak Research Articles

The NMR structure of the Orf63 lytic developmental protein from lambda bacteriophage

The orf63 gene resides in a region of the lambda bacteriophage genome between the exo and xis genes and is among the earliest genes transcribed during infection. In lambda phage and Shiga toxin (Stx) producing phages found in enterohemorrhagic Escherichia coli (EHEC) associated with food poisoning, Orf63 expression reduces the host survival and hastens the period between infection and lysis thereby giving it pro-lytic qualities. The NMR structure of dimeric Orf63 reveals a fold consisting of two helices and one strand that all make extensive intermolecular contacts. Structure-based data mining failed to identify any Orf63 homolog beyond the family of temperate bacteriophages. A machine learning approach was used to design an amphipathic helical ligand that bound a hydrophobic cleft on Orf63 with micromolar affinity. This approach may open a new path towards designing therapeutics that antagonize the contributions of Stx phages in EHEC outbreaks.

The Epidemiological and Clinical Characteristics of the Largest Outbreak of Enterohemorrhagic Escherichia coli in Korea.

The largest outbreak of enterohemorrhagic Escherichia coli (EHEC) O157:H7 occurred at a preschool in South Korea from June 12 to 29, 2020. This study aimed to analyze the epidemiological and clinical characteristics of EHEC infection in this outbreak. Epidemiological investigation was performed on all 184 children and 19 workers at the preschool using a standard questionnaire to assess symptoms, food intake, attendance, and special activity history. Pulsed-field gel electrophoresis analysis of confirmed cases was performed to determine genetic relevance. During this outbreak, 103 children were affected, whereas only one infection was identified in adults. Of the 103 pediatric patients, 85 had symptoms (82.5%), including diarrhea, abdominal pain, bloody stool, fever, and vomiting. Thirty-two patients (31.1%) were hospitalized, 15 (14.6%) were diagnosed with hemolytic uremic syndrome, and 4 (3.9%) received dialysis treatment. Pulsed-field gel electrophoresis analysis identified 4 genotypes with high genetic relevance (92.3%). Epidemiological investigation revealed that this outbreak might have occurred from ingesting foods stored in a refrigerator with a constant temperature above 10°C, which was conducive to bacterial growth. Despite several measures after outbreak recognition, new infections continued to appear. Therefore, the preschool was forced to close on June 19 to prevent further person-to-person transmission. Our findings from the response to the largest outbreak will help prepare countermeasures against future EHEC outbreak.

Bacteriophage Transcription Factor Cro Regulates Virulence Gene Expression in Enterohemorrhagic Escherichia coli

Bacteriophage-encoded genetic elements control bacterial biological functions. Enterohemorrhagic Escherichia coli (EHEC) strains harbor lambda-phages encoding the Shiga-toxin (Stx), which is expressed during the phage lytic cycle and associated with exacerbated disease. Phages also reside dormant within bacterial chromosomes through their lysogenic cycle, but how this impacts EHEC virulence remains unknown. We find that during lysogeny the phage transcription factor Cro activates the EHEC type III secretion system (T3SS). EHEC lambdoid phages are lysogenic under anaerobic conditions when Cro binds to and activates the promoters of T3SS genes. Interestingly, the Cro sequence varies among phages carried by different EHEC outbreak strains, and these changes affect Cro-dependent T3SS regulation. Additionally, infecting mice with the related pathogen C.rodentium harboring the bacteriophage cro from EHEC results in greater T3SS gene expression and enhanced virulence. Collectively, these findings reveal the role of phages in impacting EHEC virulence and their potential to affect outbreak strains.

The 2011 German Enterohemorrhagic Escherichia Coli O104:H4 Outbreak-The Danger Is Still Out There.

Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin (Stx) producing bacteria causing a disease characterized by bloody (or non-bloody) diarrhea, which might progress to hemolytic uremic syndrome (HUS). EHEC O104:H4 caused the largest ever recorded EHEC outbreak in Germany in 2011, which in addition showed the so far highest incidence rate of EHEC-related HUS worldwide. The aggressive outbreak strain carries an unusual combination of virulence traits characteristic to both EHEC-a chromosomally integrated Stx-encoding bacteriophage, and enteroaggregative Escherichia coli-pAA plasmid-encoded aggregative adherence fimbriae mediating its tight adhesion to epithelia cells. There are currently still open questions regarding the 2011 EHEC outbreak, e.g., with respect to the exact molecular mechanisms resulting in the hypervirulence of the strain, the natural reservoir of EHEC O104:H4, and suitable therapeutic strategies. Nevertheless, our knowledge on these issues has substantially expanded since 2011. Here, we present an overview of the epidemiological, clinical, microbiological, and molecular biological data available on the 2011 German EHEC O104:H4 outbreak.

Enterohemorrhagic Escherichia coli: A versatile pathogen that should be under surveillance

Out of bacteria which cause food –borne infections, enterohemorrhagic Escherichia coli (EHEC) is well known to be pathogen causing serious outbreaks. The first outbreak of EHEC infection occurred in 1982 was due to ingestion of hamburger at restaurant. A rare Escherichia coli serotype, 0157:H7 was isolated at that time and the following outbreaks were mostly due to this serotype. However, O26, O111 and O104 were also responsible for EHEC outbreaks. Enterohemorrhagic E. coli is an important food and water-borne pathogen. Verotoxins (VTs) produced by this pathogen causes painful hemorrhagic colitis along with major complications of hemolytic uremic syndrome (HUS). The morbidity and significantly high mortality and enormous economic loss are problematic to the health care administrators and EHEC infection is a serious public health issue. Another factor which makes it high transmissibility is the low infectious dose. The German O104:H4 epidemic was caused by the pathogen carrying a combination of virulence genes derived from two well-known pathogens, EHEC and enteroaggregative E. coli (EAEC). There is a possibility that two mobile DNA elements can occur again in this versatile pathogen. In this article, some aspects of EHEC infections which were established but not well known to the medical personals were explained to get understanding of why this infection should not be overlooked and should be under surveillance.

Enterohemorrhagic Escherichia coli outbreaks related to childcare facilities in Japan, 2010-2013.

BackgroundEnterohemorrhagic Escherichia coli (EHEC) is an important cause of gastroenteritis in Japan. Although non-O157 EHEC infections have been increasingly reported worldwide, their impact on children has not been well described.MethodsWe collected national surveillance data of EHEC infections reported between 2010 and 2013 in Japan and characterized outbreaks that occurred in childcare facilities. Per Japanese outbreak investigation protocol, faecal samples from contacts of EHEC cases were collected regardless of symptomatic status. Cases and outbreaks were described by demographics, dates of diagnosis and onset, clinical manifestations, laboratory data, and relation to specific outbreaks in childcare facilities.ResultsDuring 2010–2013, a total of 68 EHEC outbreaks comprised of 1035 cases were related to childcare facilities. Among the 66 outbreaks caused by a single serogroup, 29 were serogroup O26 and 22 were O157; 35 outbreaks were caused by stx1-producing strains. Since 2010, the number of reported outbreaks steadily increased, with a rise in cases and outbreaks caused by stx1-producing O26. Of 7069 EHEC cases reported nationally in 2010–2011, the majority were caused by O157 (n = 4938), relative to O26 (n = 1353) and O111 (n = 195). However, relative to 69 cases of O157 (2 %) associated with childcare facility EHEC outbreaks, there were 131 (10 %) such cases of O26, and this trend intensified in 2012–2013 (O157, 3 %; O26, 24 %; O111, 48 %). Among family members of childcare facility cases, the proportion of cases that were symptomatic declined with age; 10/16 cases (63 %) aged 6 years or younger, 16/53 cases (30 %) 6–19 years old, 23/120 cases (19 %) 20–49 years old and 2/28 cases (7 %) 50 years or older were symptomatic. Thirty one of the 68 outbreaks (46 %) were classified as foodborne-related.ConclusionsChildcare facility EHEC outbreaks due to non-O157 serogroups, particularly O26 and O111, increased during 2010–2013. These facilities should pay extra attention to health conditions in children. As older family members of childcare facility cases appear to be less symptomatic, they should be vigilant about hand-washing to prevent further transmission.

Analyzing Consumers' Reactions to News Coverage of the 2011 Escherichia coli O104:H4 Outbreak, Using the Extended Parallel Processing Model

This article describes and analyzes Flemish consumers' real-life reactions after reading online newspaper articles related to the enterohemorrhagic Escherichia coli (EHEC) O104:H4 outbreak associated with fresh produce in May and June 2011 in Germany. Using the Extended Parallel Processing Model (EPPM) as the theoretical framework, the present study explored the impact of Flemish (Belgian) online news coverage on consumers' perception of the risk induced by the EHEC outbreak and their behavioral intentions as consumers of fresh produce. After the consumers read a newspaper article related to the outbreak, EPPM concepts were measured, namely, perceived severity, susceptibility, self-efficacy, and affective response, combined with behavioral intentions to eat less fresh produce, to rinse fresh produce better, and to alert loved ones concerning the risk. The consumers' reactions were measured by inserting a link to an online survey below every online newspaper article on the EHEC outbreak that appeared in two substantial Flemish newspapers. The reactions of 6,312 respondents were collected within 9 days for 17 different online newspaper articles. Looking at the perceived values of the EPPM concepts, the perceived severity and the perceived susceptibility of the risk were, as expected, high. However, the consumers thought they could prevent the risk from happening, which stresses the importance of increasing consumers' knowledge of emerging food safety risks. Furthermore, analyses showed the moderating role of government trust and its influence on the way consumers perceived the risk, how worried they were, and their behavioral intentions.

Krankenhaushygiene: Umgang mit einem EHEC-Ausbruch

During May and June 2011 an outbreak of enterohemorrhagic Escherichia coli (EHEC) occurred in Germany. More than 4000 patients were infected of which 800 developed hemolytic uremic syndrome (HUS) as a severe complication. Reports in the press led to great concern in the general population. Many people with diarrhea reported to hospitals in order to exclude EHEC infections. We describe the management of patients with suspected infectious diarrhea at the university hospital of Essen. A hospital with a significant number of immunocompromised patients. One important measure to handle the surge of contagious patients was to establish a multidisciplinary coordination team under leadership and guidance of the Department of Nephrology and the Department of Hospital Hygiene. Suspected infectious patients were separated in a modified emergency room. A new ward for infectious diseases was established to isolate in-patients. In our hospital the management of EHEC outbreak enabled us to treat these additional infectious patients without hampering the treatment of the other patients. As a result we plan the implementation of a coordination team for future epidemics.

Enterohemorrhagic E. coli (EHEC) pathogenesis

Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a human pathogen responsible for outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. Conventional antimicrobials trigger an SOS response in EHEC that promotes the release of the potent Shiga toxin that is responsible for much of the morbidity and mortality associated with EHEC infection. Cattle are a natural reservoir of EHEC, and approximately 75% of EHEC outbreaks are linked to the consumption of contaminated bovine-derived products. This review will discuss how EHEC causes disease in humans but is asymptomatic in adult ruminants. It will also analyze factors utilized by EHEC as it travels through the bovine gastrointestinal (GI) tract that allow for its survival through the acidic environment of the distal stomachs, and for its ultimate colonization in the recto-anal junction (RAJ). Understanding the factors crucial for EHEC survival and colonization in cattle will aid in the development of alternative strategies to prevent EHEC shedding into the environment and consequent human infection.

High Stability of Stx2 Phage in Food and under Food-Processing Conditions

Bacteriophages (phages) carrying Shiga toxin genes constitute a major virulence attribute in enterohemorrhagic Escherichia coli (EHEC). Several EHEC outbreaks have been linked to food. The survival of such strains in different foods has received much attention, while the fate of the mobile Shiga toxin-converting phages (Stx phages) has been less studied. We have investigated the stability of an Stx phage in several food products and examined how storage, food processing, and disinfection influence the infectivity of phage particles. The study involved a recombinant Stx phage (Δstx::cat) of an E. coli O103:H25 strain from a Norwegian outbreak in 2006. Temperature, matrix, and time were factors of major importance for the stability of phage particles. Phages stored at cooling temperatures (4°C) showed a dramatic reduction in stability compared to those stored at room temperature. The importance of the matrix was evident at higher temperatures (60°C). Phages in ground beef were below the detection level when heated to 60°C for more than 10 min, while phages in broth exposed to the same heating conditions showed a 5-log-higher stability. The phages tolerated desiccation poorly but were infective for a substantial period of time in solutions. Under moist conditions, they also had a high ability to tolerate exposure to several disinfectants. In a dry-fermented sausage model, phages were shown to infect E. coli in situ. The results show that Stx phage particles can maintain their infectivity in foods and under food-processing conditions.

Infectious colitis

The incidence of gastrointestinal infections continues to increase and infectious colitis contributes to significant morbidity and mortality worldwide. The purpose of this review is to highlight the recent advances in knowledge of pathogens causing infectious colitis. We describe the various pathogens and specifically focus on enterohemorrhagic Escherichia coli (EHEC) O157:H7, Salmonella, Shigella, Campylobacter, and Entamoeba histolytica infections, and their impact on long-term effects, including postinfectious irritable bowel syndrome and inflammatory bowel disease. Salmonella, Campylobacter, and EHEC outbreaks continue to occur with disturbing regularity. Peanut butter and peppers were recently responsible for outbreaks of nontyphoid Salmonella. Recent research has identified Salmonella genes required for colonization of various hosts and transposon-mediated differential hybridization was recently used to identify genes required during infection in different animal models. A number of other strains of EHEC in addition to O157:H7 are emerging as serious threats to food safety in the USA. Campylobacter jejuni isolates are of interest because of absence of genes encoding for classical enterotoxins, and lack of plasmids encoding genes promoting bacterial invasion. Recent research has identified that the organism is able to invade and replicate in infected epithelia via Toll-like receptor (TLR)-2 and TLR-4. Also patients with infectious colitis, in particular Salmonella and Campylobacter, are at increased risk of postinfectious irritable bowel syndrome and inflammatory bowel disease on long-term follow-up. The paradigm of Entamoeba histolytica infection is changing with recent reports of detection of E. dispar deoxyribonucleic acid sequences, previously considered nonpathogenic. There has been an explosion in the understanding of the epidemiology, pathobiology, and mechanisms underlying infectious colitis. Additional studies to address prevention strategies and strict screening modalities for these infections are necessary.

Factors influencing the development of hemolytic uremic syndrome caused by enterohemorrhagic Escherichia coli infection: from a questionnaire survey to in vitro experiment.

Enterohemorrhagic Escherichia coli (EHEC) is known as an etiological agent of not only hemorrhagic colitis, but also hemolytic uremic syndrome (HUS) and other serious complications. In this paper, a summary of the results, especially in relation to possible factors involving HUS complication, of a questionnaire survey conducted on the occasion of the massive EHEC outbreak in Sakai city in 1996, is presented. A brief review of the virulence factors and pathogenic mechanism involved in the development of HUS in EHEC infection is also described.

Summary: Nagasaki enterohemorrhagic Escherichia coli meeting and workshop.

In Nagasaki on 14-16 November 1996, the Japanese Panel on Cholera and Related Diarrheal Diseases of the US-Japan Cooperative Medical Science Program hosted the first international conference on enterohemorrhagic Escherichia coli (EHEC) and other diarrheal diseases since the devastating 1996 outbreaks in Japan and the United States. There were a series of presentations on the ecology, detection, genetics, epidemiology, pathogenesis, and impact of and vaccine developments for Vibrio cholerae, E. coli, Salmonella, Shigella, and Yersinia infections. These were followed by 1.5 days of presentations on the EHEC outbreaks in Japan and in the United States and the clinical manifestations, pathogenesis, and potential intervention strategies, including immunoprophylaxis. There was also a workshop on new directions and potential basic and clinical research collaborations relevant to EHEC and other diarrheal diseases.