Hemorrhagic Uremic Syndrome Research Articles

Characteristics of Enterohaemorrhagic Escherichia coli in Jeju Province, Korea: a study of registry routes from 2017 to 2023

Enterohemorrhagic Escherichia coli (EHEC) produces Shiga toxin, which causes diarrhea, hemorrhagic colitis, and hemorrhagic uremic syndrome. The Korea Center for Disease Control and Prevention (KCDC) has designated EHEC as a legal infectious disease and has conducted laboratory surveillance. This study aimed to compare the demographic, epidemiological, clinical, and laboratory characteristics of EHEC cases in Jeju Province between August 2017 and November 2023, notified by two registry routes. The data were sourced from the integrated disease health and health management system managed by the KCDC. Cases reported due to experiencing gastrointestinal symptoms, or contacts of each case were defined as the “symptomatic” group. In contrast, cases with positive findings during a health checkup or laboratory surveillance were defined as the “screening” group. The symptomatic and screening groups had 35 and eight patients, respectively. There were significant differences in the age and seasonal distribution. The selection group was 20-59 years old in the main age distribution and registered evenly throughout the four seasons. In comparison, the symptomatic group was younger or older and not registered in the winter. These findings may be used to establish a more appropriate surveillance system for diarrheal outbreaks.

Public Health Significance of Verocytotoxigenic Escherichia coli: An Overview

Meat is a global vital protein source catering to diverse diets. By 2050, world’s population may rise to 9 billion and the demand for meat will exceed supply, necessitating a doubling of meat production. Nutritionally rich composition makes meat, a fertile ground for numerous microbes, leading to spoilage and foodborne illnesses, impacting human health. External factors like poor hygiene, inadequate post-production storage, mishandling and more contribute to meat contamination. The zoonotic strains of E. coli can cause severe food poisoning, with over 700 identified serotypes, hence it is crucial to identify, monitor and control E. coli to ensure food safety. Among E. coli pathotypes, Verocytotoxigenic E. coli (VTEC) stands out as major cause of food poisoning. The VTEC toxin (Shiga toxin), can induce mild diarrhea to severe form of illness like Hemorrhagic Uremic Syndrome and Hemorrhagic Colitis, posing a severe public health risk. The Cattle is a primary reservoir for VTEC, which, by faecal shedding, can pollute food, water and the environment. Furthermore, E. coli can spread through contaminated meat, raw milk and milk products. This bacterium is commonly found in the immediate surroundings of animal reservoir, including soil, grass and manure, leading to potential contamination of milk. E. coli infections not only impact humans but also animals, with cattle, sheep and poultry acting as reservoirs for different E. coli strains. Cattle populations frequently harbor E. coli O157:H7 asymptomatic carriers, contributing to faecal contamination of food and water sources. Educating the public about the risks associated with improper meat handling and contamination is essential to reduce foodborne illnesses. Monitoring and surveillance of meat quality in local markets, as are crucial steps towards ensuring food safety. This underscores the importance of understanding and managing E. coli contamination in meat to safeguard public health and ensure the safety of meat products in the global food supply chain.

RETROSPECTIVE STUDY ON THE DISTRIBUTION OF E. COLI ENTERITIS IN BULGARIA FOR A PERIOD OF TEN YEARS (2011-2020)

BACKGROUND. Intestinal diseases caused by diarrheagenic E. coli account for a significant proportion of infections, especially in children. E. coli enteritis can occur as sporadic cases but often assumes an epidemic nature. This study aims to determine the significance and prevalence of infections caused by diarrheagenic E. coli in Bulgaria for a period of ten years 2011-2020. MATERIALS AND METHODS. The etiological role and distribution of diarrheagenic E. coli among Bulgarian population for the last decade were determined by a retrospective analysis of microbiological and epidemiological data. RESULTS. Data from the studied period reveal the role of enterotoxigenic E. coli (ETEC) O6 as a leading etiological cause of epidemic and sporadic enteritis in the country, followed by enteropathogenic E. coli (EPEC) O126 and O127. There are only two reported cases of lethal hemorrhagic uremic syndrome (HUS) caused by enterohemorrhagic E. coli (EHEC) that happened in 2011. Most affected by diarrheagenic E. coli (DEC) infections are infants and young children. Neonatal meningitis in Bulgaria is rare, the etiological agents are E. coli O18 and O25. The most common registered DEC infections are during the summer months of May - September. Several epidemics have been registered in young children, and the etiological cause is ETEC O6. CONCLUSION. The main etiological agent of E. coli infections in Bulgaria is ETEC O6, and infants and young children are at risk. Recent DEC epidemics have not been reported. The ethiologic diagnosis of infections is underestimated, which is a risk factor for increasing the number of healthy carriers, outbreaks and unlimited agent spreading through the food chain.

Differentiation of stx1A gene for detection of Escherichia coli serotype O157: H7 and Shigella dysenteriae type 1 in food samples using high resolution melting curve analysis.

Escherichia coli serotype O157: H7 and Shigella dysenteriae type 1 as the Shiga toxin‐producing bacteria cause some acute gastrointestinal and extraintestinal diseases such as hemorrhagic uremic syndrome and bloody diarrhea in human. Stx genes are the key virulence factors in these pathogens. The aim of this study was to develop HRMA assay to differentiate stx1A gene for detection of E. coli serotype O157: H7 and Sh. dysenteriae type 1 and determine the prevalence of these pathogens in food samples using this method. PCR‐HRMA assay and gold standard methods have been carried out for identification of pathogens among 135 different food samples. We found HRMA method a sensitive and specific assay (100 and 100%, respectively) for differentiation of stx1A gene, consequently, detection of these pathogens in food samples. Also, the highest prevalence of E. coli serotype O157: H7 and Sh. dysenteriae type 1 harboring stx1A gene was observed in raw milk and vegetable salad samples, respectively. HRMA as a rapid, inexpensive, sensitive and specific method is suggested to be used for differentiation of stx1A gene to detect E. coli serotype O157: H7 and Sh. dysenteriae type 1 as the key pathogens for safety evaluation of food samples.

Immunogenic Evaluation of Bivalent Vaccine Candidate against Enterohemorrhagic and Enterotoxigenic Escherichia coli.

Caused by bacterial, viral, and parasitic pathogens, diarrhea is the second leading cause of death among children under five. Two strains of E. coli, namely Enterotoxigenic, ETEC and Enterohemorrhagic EHEC are the most important causes of this disease in developing countries. EHEC is a major causative agent of bloody diarrhea and hemorrhagic uremic syndrome, while ETEC is the most important cause of diarrhea in neonates and travelers. To evaluate the immunologic properties of a subunit vaccine candidate comprising the main immunogenic epitopes from these two bacterial strains. The construct comprised of LTB and CfaB antigens from ETEC, and Intimin and Stx2B antigens from EHEC, was designed, analyzed and synthesized using bioinformatics methods. The chimeric gene was sub-cloned in the expression vector and expressed in E. coli host. The purified chimera protein was injected subcutaneously into the experimental animals. The production of specific antibodies was confirmed by immunological methods, and the protection capacity was evaluated by the challenge of immunized mice with the pathogenic bacteria. Chimeric recombinant protein was able to increase IgG titer. Neutralization assay indicated that the antibodies generated against LtB moiety were able to neutralize ETEC toxin. In animal challenge study, all non-immune mice died within 3 days after the injection of toxin, but all immunized mice survived from Stx toxin. The immunity to both ETEC and EHEC bacteria is significant, and this structure can be considered as a candidate for vaccine production against these bacterial strains.

National outbreak of Shiga toxin-producing Escherichia coli O157:H7 linked to mixed salad leaves, United Kingdom, 2016.

We investigated a large outbreak of Escherichia coli O157 in the United Kingdom (UK) with 165 cases between 31 May and 29 July 2016. No linked cases were reported in other countries. Cases were predominately female (n = 128) and adult (n = 150), 66 attended hospital and nine had features of haemorrhagic uraemic syndrome. A series of epidemiological studies (case–control, case–case, ingredients-based and venue-based studies) and supply chain investigations implicated mixed salad leaves from Supplier A as the likely outbreak vehicle. Whole genome sequencing (WGS) indicated a link with strains from the Mediterranean and informed the outbreak control team to request that Supplier A cease distributing salad leaves imported from Italy. Microbiological tests of samples of salad leaves from Supplier A were negative. We were unable to confirm the source of contamination or the contaminated constituent leaf although our evidence pointed to red batavia received from Italy as the most likely vehicle. Variations in Shiga toxin-producing E. coli surveillance and diagnosis may have prevented detection of cases outside the UK and highlights a need for greater standardisation. WGS was useful in targeting investigations, but greater coverage across Europe is needed to maximise its potential.

Isolation of Shiga toxin-producing strains of Escherichia coli from beef and swine carcasses and the characterization of their genes

Escherichia coli is part of the normal microflora of the intestinal tract of humans and warm-blooded animals, but its presence in raw material and food of animal origin is considered as fecal contamination and can be very dangerous for consumers. The determination of the number of E. coli in raw material and food is important because among them can be pathogenic strains. The most dangerous strains are considered enterohemorrhagic E. coli as a causative agent of severe bloody diarrhea and hemorrhagic uremic syndrome in humans through the production of Shiga-toxin, which is the main virulence factor, responsible for disease. The aim of this study was to identify the prevalence of Shiga toxin-producing strains of E. coli (STEC) from swabs of beef and swine carcass in slaughterhouses in Ukraine and characterize their genes, which are responsible for pathogenic properties. A total of 230 samples of swabs from beef (130) and swine (100) carcasses were obtained from 5 slaughterhouses in Ukraine between 2012 and 2015. Samples of swabs from carcasses were randomly selected at the final point of the process after the final washing of the carcass from the following areas: distal hind limb, abdomen (lateral and medial) from swine carcasses, brisket, flank and flank groin areas from beef carcasses. All samples were examined by culture-dependent method, after that each positive isolate of STEC was analyzed by multiplex PCR to detect the stx1, stx2, and eae genes. Out of 230 collected samples, seven (7.2%) were contaminated with STEC. The highest prevalence of STEC was found in swabs from beef carcasses (8.1%) in comparison to swabs from swine carcasses (5.7%). The stx1 gene was the predominant gene detected in all STEC positive samples. The eae gene was found in one of the examined isolates from beef carcass. Three isolates from swabs of beef carcass carried both stx1 and stx2 genes, one isolate showed association between stx1 and eae genes, one isolate was positive for stx1 gene only. In swabs from swine carcasses (2 isolates) stx1 and stx2 genes were presented simultaneously. The results of this study suggested that fresh raw meat could be a potential vehicle for transmission of the Shiga toxin-producing strain of E. coli to humans. This is the first report of STEC prevalence in beef and swine carcasses in Ukraine and these data will be valuable for microbiological risk assessment and help the appropriate services to develop strategies to mitigate health risk.

Prevalence, quantification and isolation of pathogenic shiga toxin Escherichia coli O157:H7 along the production and supply chain of pork around Hubei Province of China

Shiga toxin Escherichia coli (STEC) O157:H7 is an important zoonotic food borne pathogen causing gastroenteritis that may lead to life threatening hemorragic colitis (HC) and hemorrhagic uremic syndrome (HUS). 325 meat and tissue samples were tested for enumeration of O157:H7 strains using most probable number (MPN)-PCR targeting their specific genes flicH7 and rfbO157 followed by isolation, sereotyping and pathogenicity testing. The overall prevalence of O157:H7 was 41.3% (134/325) along the production and supply chain of pork (PSCP), being higher in supply chain (59%, 118/200) as compared to pig farms (12.8%, 16/125). Along the PSCP, the highest prevalence was found in slaughter houses (86.25%, 69/80) followed by wet- (53.3%, 32/60) and super-markets (28.3%, 17/60). The MPN values ranged from 3 to 1100 MPN/g in overall positive samples, being higher in slaughter houses followed by wet and super markets. Except from intestine and meat samples of slaughter house, the MPN was found higher in summer as compared to winter samples. Eight STEC O157:H7 isolated from meat and liver samples were tested in Balb/C mice for pathogenicity. After development of clinical signs and symptoms, 50–83.3% mortality was produced in the infected mice. Histopathological investigations revealed visible necrosis of intestinal epithelial cells, shedding of cellular debris in the intestine, while in the kidney, necrosis of renal cortical portion of tubular epithelial cells was observed. STEC O157:H7 is prevalent along PSCP around Hubei of China in different proportions being alarmingly higher in supply chain and markets which is a matter of concern for public health.

Coma caused by Shigella toxin-producing Escherichia coli in the absence of haemorrhagic uraemic syndrome (HUS).

Shigella toxin-producing Escherichia coli (STEC) is well known for its complications such as haemolytic uraemic syndrome (HUS), but neurological symptoms have also been reported. While most cases of infection with STEC occur with concurrent HUS, we describe a patient with severe neurological symptoms in the absence of HUS.LEARNING POINTSShigella toxin producing Escherichia coli (STEC) are bacteria that cause haemorrhagic colitis.Generally, infections with STEC occur with a concurrent haemolytic uraemic syndrome (HUS).However, infections with STEC can occur with neurological symptoms without HUS.

LeuO enhances butyrate-induced virulence expression through a positive regulatory loop in enterohaemorrhagic Escherichia coli.

Enterohaemorrhagic Escherichia coli (EHEC) causes bloody diarrhoea and other severe symptoms such as haemorrhagic uraemic syndrome. The expression of virulence genes on the locus for enterocyte effacement (LEE) and associated genes is regulated by a variety of factors, including transcriptional regulators and environmental signals. Butyrate, one of the major short-chain fatty acids present in the intestine, enhances expression of LEE genes and flagella biosynthesis genes in EHEC O157:H7, resulting in increased bacterial adherence and motility. Here, we show that expression of the leuO gene, which encodes a LysR-type transcriptional regulator, is enhanced by butyrate via Lrp, which is also necessary for butyrate-induced responses of LEE genes. LeuO expression induces prolonged activation of the promoter of LEE1 operon, including the ler gene, as well as virulence mechanisms such as microcolony formation. Activation of the LEE1 promoter by LeuO depends on another regulator, called Pch. The response of the leuO promoter to butyrate requires two virulence regulators, Pch and Ler, in addition to Lrp. Pch, Ler and Lrp bind the upstream region of the leuO promoter. Thus, leuO is involved in butyrate-enhanced expression of LEE genes through a positive feedback mechanism, but its expression and action on the LEE1 promoter are dependent on the virulence regulators Pch and Ler.

A Through-chain Analysis of Food Safety Hazards and Control Measures Associated with the Production and Supply of Seed Sprouts for Human Consumption

Background: Seed sprouts contaminated with pathogenic microorganisms, such as Salmonella spp. and Shiga toxin-producing Escherichia coli (STEC) present an unacceptable health risk to consumers. An outbreak that occurred in Australia during 2005 and 2006 due to the consumption of alfalfa sprouts contaminated with Salmonella Oranienburg resulted in 141 infected cases, and cost an estimated $1.19 million to the Australian community. In Japan in 1996, consumption of radish sprouts contaminated with STEC O157:H7 affected more than 10,000 individuals. The outbreak of E. coli O104:H4 linked to the consumption of fenugreek sprouts that occurred in Europe in 2011 was an unprecedented foodborne outbreak. More than 4,000 individuals were infected by STEC O104:H4. Among them, 908 developed haemorrhagic uraemic syndrome (HUS), and 50 died of STEC infection. This demonstrates the potential food safety risk arising from seed sprouts and that the consequences can be devastating. Food Standards Australia New Zealand (FSANZ) initiated the development of a primary production and processing standard for seed sprouts in 2009 to enhance the safety of seed sprouts produced and sold in Australia. After extensive consultations with the State and Territory food safety regulators, and a thorough investigation of the Australian Grey Literature European Journal of Nutrition & Food Safety, 4(4): 424-428, 2014 425 industry practices in producing seed sprouts for human consumption, a technical paper was prepared to inform the design of potential risk mitigation measures for a national food safety standard on seed sprout production. This technical paper described the Australian seed sprout industry, depicted the steps involved in the production of seed sprouts for human consumption, and provided an analysis of potential food safety hazards that could occur during seed sprout production and processing. A food safety standard for the production and sale of seed sprouts in Australia was finalised in November 2011. This extended abstract describes the key aspects of the technical paper. Aims: To provide technical and scientific information to support risk management decisions aimed at maximizing the safety of seed sprouts produced for human consumption in Australia. Study Design: A through-chain qualitative food safety risk analysis. Place and Duration of Study: FSANZ, Canberra, Australia, between July 2009 and January 2010. Methodology: This through-chain risk analysis was prepared upon a comprehensive review of literature available at the time on: investigations of foodborne outbreaks associated with consumption of seed sprouts; surveys of microbial contamination of seed sprouts; specific publications on crop production, seed harvest, post-harvest processing and storage of seeds; production of seed sprouts; risk assessments on seed sprouts; and regulatory guidelines published by Australian and international food safety regulatory authorities on seed sprouts. Members of the FSANZ project team conducted field studies of sprout production, lucerne crop production, lucerne seed processing, wholesale and retail sale of seed sprouts. A survey was conducted on the variety, volume and value of sprouts produced, source and quantity of seeds used to produce sprouts for human consumption, trend of consumption of seed sprouts in Australia, as well as the size and the location of sprout producers in Australia. Stakeholders were consulted through a FSANZ standard development committee with participants from State and Territory food safety regulators, peak sprout producer industry bodies, seed producers and seed processors, major food retailers, and consumer representatives. The through-chain analysis of food safety hazards associated with the production and processing of seed sprouts was prepared in line with the principles of hazard analysis critical control points (HACCP).

Novel fusion protein protects against adherence and toxicity of enterohemorrhagic Escherichia coli O157:H7 in mice

Infection with Escherichia coli (E. coli) O157:H7 may develop into bloody diarrhea, or hemorrhagic uremic syndrome (HUS), which usually causes kidney failure or even death. Considered as the pathogenesis mechanism of E. coli O157:H7 infection, attachment or adhesion that is directly mediated by intimin is the first step of E. coli O157:H7 interaction with its host, and all these serious sequelae are mainly due to Shiga toxins (Stxs) released by E. coli O157:H7. In this study, a novel SSI fusion protein that contains the critical toxin-antigens Stx2B and Stx1B, and the critical adhesion-antigen fragment Int281 was constructed. The protein induced complete immune protection, with both anti-toxin and anti-adhesion effects. The dominant increase in IgG1 and the high level of Th2-typical cytokine (IL-4 and IL-10) expression showed that SSI significantly induced Th2-mediated humoral immune response. In the mouse model, the SSI fusion protein not only elicited neutralizing antibodies against both Stx1 and Stx2 toxins, but also induced a high level of anti-adhesion antibodies. The SSI-immunized mice did not show any pathologic changes. SSI provides evident protection with two-time immunization against a highly lethal dose of E. coli O157:H7.

Neonatal hemolytic uremic syndrome after mother-to-child transmission of Escherichia coli O157

About 90% of cases of hemorrhagic uremic syndrome (HUS) occur in early childhood and most frequently are preceded by bloody diarrhea due to shiga-like toxin (SLT) producing Escherichia coli. We report a case of a newborn girl presenting with bloody diarrhea on her 7th day of life. Acute renal failure, severe arterial hypertension and hemolytic anemia were detected and prompt peritoneal dialysis and antihypertensive therapy were required. The girl had several episodes of seizures, necessitating intravenous phenobarbital. Transfontanel ultrasonography 48 h after disease onset was normal, whereas, MRI investigation 10 days later revealed severe ischemic lesions with beginning cystic encephalopathy. Renal function recovered and only very moderate tubular dysfunction remained. Serum analysis of factor H, von Willebrand factor protease, homocystinemia, proteins C and S, and antithrombin III were all normal. Mutation analysis of factor V Leiden, factor II, and methyltetrahydrofolate-reductase were normal. E. coli 0157:H7 and SLT 2 were detected in the stool. SLT 2 was also found in the mother's stool. This is the first report of mother-to-child transmission of SLT-producing E. coli.

Enterohemorrhagic Escherichia coli (EHEC)

Enterohaemorrhagic Escherichia coli has since the last 2 decades been known to cause severe and bloody diarrhoea as well as haemorrhagic colitis (HC) and haemorrhagic uraemic syndrome (HUS) especially among children. The importance of screening for EHEC among children and older patients with severe symptoms is apparent. Production of the verocytotoxins VT1 and VT2 are the main features of EHEC, and the VT types and mode of action during human infection is described. There are, however, other features adding to the pathogenicity. In this review we deal with the importance of properties such as fimbriae and adhesins as well as systems to meet the bacterial need for iron during infection. These factors are probably important for the establishment of EHEC in the gut and add to the bacterial virulence. It has now become evident that VT producing E. coli, irrespective of serogroup, might be human pathogens. We conclude that knowledge of the different possible virulence factors adds to the possibility of separating more virulent from less virulent isolates.

Pathogenesis of Escherichia coli O157:H7 in weaned calves.

Cattle are an important reservoir of Shiga toxin-producing Escherichia coli O157:H7 and other enterohemorrhagic E. coli (EHEC) that cause diarrhea, hemorrhagic colitis, and hemorrhagic uremic syndrome in humans. One strategy for reducing human foodborne EHEC infections is to reduce the levels of EHEC in cattle. Bovine O157:H7 infection models will facilitate identification of virulence factors involved in bovine infections. O157:H7 cause severe diarrhea and attaching and effacing (A/E) mucosal lesions in colostrum-deprived neonatal (< 2 h) calves. We hypothesized that O157:H7 also cause A/E lesions in older calves, but these were not detected in earlier studies because intestinal levels of O157:H7 were too low (< 10(6) CFU/g of tissue) for detection of focally distributed microscopic lesions. Weaned 3- to 4-month-old calves were fasted 48 h, inoculated via stomach tube with 10(10) CFU of O157:H7 or nonpathogenic E. coli, necropsied 4 d pi and examined histologically. Calves inoculated with O157:H7 had higher intestinal levels of inoculated E. coli than control animals. The rectum was the major site of colonization. A/E lesions were seen in the rectum and cecum of calves with high levels of O157:H7. Weaned calves, like neonatal calves, are susceptible to intestinal damage induced by EHEC O157:H7. The rectum and cecum may be principal sites of EHEC O157:H7 colonization during the carrier-shedder state in cattle.

Pathogenesis of O157:H7 Escherichia coli infection in neonatal calves.

Cattle have been implicated as an important reservoir of Shiga-like toxin-producing Escherichia coli (SLTEC) O157:H7, enterohemorrhagic E. coli (EHEC) that cause hemorrhagic colitis and hemorrhagic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed low levels of E. coli O157:H7 long-term, but little is known about the pathogenesis of E. coli O157:H7 infection in cattle. E. coli O157:H7 induce characteristic attaching and effacing (A/E) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets and this model is used to study the pathogenesis of SLTEC infections. A/E lesions were not detected in histologic sections of the intestines from adult cattle or 3- to 14-week-old calves infected with E. coli O157:H7. Our objective was to determine if E. coli O157:H7 induce A/E lesions in neonatal calves. Colostrum-deprived calves (< 12-h-old) were bottle-fed with antibiotic-free milk replacer containing 10(10) colony forming units (CFU) of O157:H7 (SLT-I+, SLT-II+) or nonpathogenic E. coli, necropsied 18 h postinfection and their intestines examined histologically. Bacterial attachment, effacement of microvillous borders, and destruction of epithelium were observed in the intestines of the neonatal calves inoculated with E. coli O157:H7. No lesions were observed in calves inoculated with nonpathogenic E. coli. The distribution of intestinal lesions in neonatal calves resembled that in gnotobiotic pigs. Neonatal calves are apparently more susceptible to A/E lesions induced by E. coli O157:H7 than are older calves or adult cattle and provide a model for studying the pathogenesis of E. coli O157:H7 infections in cattle.