REVIEW ARTICLE Options for the control of enterohaemorrhagic Escherichia coli in ruminants (original) (raw)
Asian Journal of Research in Medical and Pharmaceutical Sciences, 2019
Consumption of foods, water, vegetables, fruits, undercooked/ground/raw meat, unpasteurized milk or milk products contaminated with the bacterium strain Escherichia coli 0157:H7 has become a serious public health concern. This strain naturally inhabits the digestive tract of healthy cattle, and is released into the environment through the faeces of the animal. This strain cause haemorrhagic enterocolitis or gastroenteritis, and then haemolytic uraemic syndrome (HUS). HUS is a disorder characterised by haemolytic anaemia, low platelet count and acute kidney failure, and this disorder is a consequence of the production and action of Shiga-like toxin produced mainly by this bacterial strain (accounting for 90 percent of all cases), and occurs mainly in children less than five (5) years of age, but also occurs in the elderly. After infection with this bacterial strain, the disorder begins with intestinal perforation and ulceration leading to bloody diarrhoea, and consequently acute kidn...
Enterotoxigenic Escherichia coli in veterinary medicine
International Journal of Medical Microbiology, 2005
Enterotoxigenic Escherichia coli (ETEC) infection is the most common type of colibacillosis of young animals (primarily pigs and calves), and it is a significant cause of diarrhoea among travellers and children in the developing world. The main virulence attributes of ETEC are adhesins and enterotoxins, which are mostly regulated on large plasmids. Almost all ETEC bacteria are known to adhere to receptors on the small intestinal epithelium by their proteinaceous surface appendages (fimbriae, pili) or by afimbrial proteins without inducing significant morphological changes. Furthermore, they secrete protein toxins (enterotoxins) to reduce absorption and to increase fluid and electrolyte secretion of small intestinal epithelial cells. Regarding details of epidemiology, pathogenesis, diagnosis and prevention of ETEC infections and diarrhoea in animals, readers are referred to an earlier more extensive review . Enterotoxigenic Escherichia coli (ETEC) in farm animals. Vet. Res. 30,. This paper intends to summarise our basic knowledge and to highlight the new developments and most actual research topics in the area of ETEC infections in veterinary medicine. Attention is paid to recently described new virulence factors and to new genetic vectors in ETEC bacteria. Applications of our knowledge in the diagnosis and prevention of ETEC diarrhoea in animals will also be discussed.
JMM Case Reports, 2015
Introduction: Enterohaemorrhagic Escherichia coli (EHEC) cause haemorrhagic colitis and haemolytic uraemic syndrome in humans. Although EHEC infection typically results in haemorrhagic colitis in all ages of human patients, in cattle it is usually limited to 1-to 5-week-old nursing calves. Case Presentation: A 1-year-old feedlot beef heifer was moribund with neurological signs and bloody diarrhoea. At necropsy, the colonic mucosa contained multiple grossly visible haemorrhagic erosions, each measuring ,1 mm in diameter. Histologically, foci corresponding to the gross erosions had E. coli O165 antigen-positive bacterial rods adherent to the apical surfaces of degenerate and necrotic colonic mucosal epithelial cells in association with attaching and effacing lesions, and also within cytoplasmic vacuoles in some of these cells. An E. coli O165 : H25 strain was isolated from the colonic mucosal tissue, and by microarray analysis was found to contain virulence genes corresponding to type III secretion system (T3SS) structure and regulation (
Enterohemorrhagic Escherichia coli (EHEC)
Scandinavian Journal of Infectious Diseases, 2005
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.
Detection and Characterization of Enterohaemorrhagic Escherichia coli in Slaughtered Cattle
Journal of Veterinary Medicine Series B-infectious Diseases and Veterinary Public Health, 1997
Fecal samples from slaughtered cattle were studied for enterohaemorrhagic Escherichia coli (EHEC) by DNA hybridization with biotin-labelled DNA probes specific for the EHEC virulence plasmid, Shiga-like toxin I (SLT I), Shiga-like toxin II (SLT II) and eae gene. Among 136 animals analysed, 47 (34.5%) were found to carry EHEC. The cytotoxic genotypes observed for EHEC strains were: 60.4% SLT I, 12.5% SLT II and 10.4% SLT I+SLT II; 16.7% resulted SLT I and SLT II negative. A total of 14 out of 48EHEC strains (29.2%) hybridized with a fimbrial probe and 14 of 48 strains with an eae probe. An important number of strains (18 out of 48) belonged to serogroups O157, O26 and O111, serogroups also commonly isolated from haemolytic uremic syndrome cases in Chile. While EHEC isolates from the same animal were usually of the same serogroup, one animal was found to carry two EHEC strains of different serogroups. A total of 50% of EHEC strains were sorbitol negative, irrespective of the O serogroup or EHEC genotypic profile. Results obtained in this study strongly suggest that cattle in Chile are a reservoir of EHEC associated with disease in humans.
Rumen contents as a reservoir of enterohemorrhagic Escherichia coli
FEMS Microbiology Letters, 1993
We investigated the role of the rumen fermentation as a barrier to the foodborne pathogen, Escherichia coli O157:H7. Strains of E. coli, including several isolates of O157:H7, grew poorly in media which simulated the ruminal environment of a well-fed animal. Strains of E. coli Ol57:H7 did not display a superior tolerance to ruminal conditions which may facilitate their colonization of the bovine digestive tract. Unrestricted growth of E. coli was observed in rumen fluid collected from fasted cattle. Growth was inhibited by rumen fluid collected from well-fed animals. Well-fed animals appear less likely to become reservoirs for pathogenic E. coli. These results have implications for cattle slaughter practices and epidemiological studies of E. coli O157:H7.
Enterohaemorrhagic Escherichia coli : emerging issues on virulence and modes of transmission
Veterinary Research, 2005
Enterohaemorrhagic Escherichia coli (EHEC) constitute a subset of serotypes (E. coli O157 and some other serogroups) of Shiga toxin (Stx)-producing E. coli (STEC) firmly associated with severe human illnesses like bloody diarrhoea and haemolytic uraemic syndrome. Stx production is essential but not sufficient for EHEC virulence. Most strains are capable of colonising the intestinal mucosa of the host with the "attaching and effacing" mechanism, genetically governed by a large pathogenicity island (PAI) defined as the Locus of Enterocyte Effacement. Other virulence factors carried by mobile genetic elements like PAI and plasmids have been recently described, and their role in the pathogenic process has not been fully elucidated. EHEC are zoonotic pathogens. They rarely cause disease in animals, and ruminants are recognised as their main natural reservoir. Cattle are considered to be the most important source of human infections with EHEC O157, and the ecology of the organism in cattle farming has been extensively studied. The organism has also been reported in sheep, goats, water buffalos, and deer. Pigs and poultry are not considered to be a source of EHEC and the sporadic reports may derive from accidental exposure to ruminant dejections. The epidemiology of EHEC infections has remarkably changed during the past ten years and an increasing number of unusual food vehicles have been associated with human infections. New routes of transmission have emerged, like contact with animals during farm visits and a wide variety of environment-related exposures. As for other zoonotic agents, having animals and raw products that are free from EHEC is not possible in practice. However, their occurrence can be minimised by applying high standards of hygiene in all the steps of the food production chain.
Prevalence of multi drug resistant Escherichia Coli in diarrheic ruminants
Benha Veterinary Medical Journal
Escherichia coli (E. coli) is the most significant cause of neonatal diarrhea in ruminants. The current study was designed to monitor the prevalence of multi-drug (MDR) resistant E. coli in diarrheic ruminants in Egypt. Rectal swab samples (n=150) were collected between November 2018 and April 2019 from diarrheic calves (n=35), lambs (n=35) and goat kids (n=80) up to 3 months from Gimmeza animal production researches station, Agriculture Research Centre (ARC), Egypt. Samples were submitted for isolation and identification of E. coli by conventional culture methods. From the examined samples , 82 (54.67%) were positive for E. coli. Among the E. coli isolates, 48 were identified as pathogenic E. coli by cultivation on Congo Red Agar and were submitted for antibiogram. Sensitivity tests revealed that 10/48 (20.83%) isolates were MDR. The 10 MDR E. coli isolates were serologically identified as O157:H7 (n=4; two isolated from calves and two from goat kids), O125 (n=3; two isolated from calves and one from lambs), O44 (n=3; two isolated from goat kids and one from lambs).
Comparative Haematology International, 2010
The presence of major virulence factors of enterohaemorrhagic Escherichia coli (EHEC; stx1, stx2, eae, Ehly) were determined among isolates from 158 diarrhoeic calves by multiplex polymerase chain reaction (PCR). Strains positive for virulence factors were subjected to serotype specific PCR assays for O157:H7 and O111 antigens. Additionally, serogroups were determined by three monovalent antisera for O26, O111 and O157 somatic
The Rabbit as a New Reservoir Host of Enterohemorrhagic Escherichia coli
Emerging Infectious Diseases, 2003
We investigated the prevalence of enterohemorrhagic Escherichia coli (EHEC) in rabbits acquired from two commercial vendors and a local petting zoo. Fecal samples from 34 Dutch Belted (DB) and 15 New Zealand White (NZW) rabbits were cultured; and isolates were biotyped, serotyped, tested by polymerase chain reaction (PCR), and genotyped by repetitive-element sequence-based PCR (Rep-PCR). Seven (25%) of 28 DB rabbits acquired from one commercial source were positive for EHEC, including O153:H-and O153:H7. One (9%) of 11 NZW rabbits from the same source was positive for eae-, stx1+ O153 strains. In contrast, six DB rabbits from another commercial source and four rabbits from a petting zoo were negative for EHEC. Rep-PCR demonstrated that the O153 EHEC and O145 enteropathogenic E. coli were two distinct clones. Our study indicates that rabbits are a new reservoir host of EHEC that may pose a zoonotic risk for humans.
Veterinary World, 2013
Aim: The trials were designed on 30 lambs of age below 2 weeks exhibiting the symptoms of colibacillosis. Materials and Methods: Isolation of organism and identification of pathogenic Escherichia coli was confirmed by standard cultural, microbiological, serological, and biochemical tests. Venous blood was collected aseptically for hematological studies. Result: Bacteriological examinations of fecal sample were positive for E.coli and isolates identified on the basis of morphological, cultural, and biochemical characteristics provided further confirmation. Hematological indices recorded significant (p > 0.05) increase in the packed cell volume, total leucocyte count, lymphocyte, and neutrophil percentage, whereas biochemical indices recorded significant decrease in the serum glucose, protein and serum albumin/ globulin levels. Treatment regimen in four different groups, suggested, gentamicin and ciprofloxacin effective drugs followed by neomycin and co-trimoxazole. Conclusion: Study suggested significant (P > 0.05) alteration in hemato-biochemical parameters whereas results indicated gentamicin and ciprofloxacin as most effective drugs.
Enteropathogenic Escherichia coli infection: history and clinical aspects
British journal of biomedical science
Diarrhoeagenic Escherichia coli remains an important cause of diarrhoeal disease worldwide. In terms of global public health, enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli are the most important. However, enterohaemorrhagic E. coli has emerged as a cause of disease in developed countries in recent years, and a number of large outbreaks have been reported. Therefore, the importance of research into diarrhoeagenic E. coli remains an important issue. EPEC is the most widespread of the diarrhoeagenic E. coli and provides a good virulence model for other E. coli infections, as well as other pathogenic bacteria. Although the virulence mechanisms of E. coli are now better understood, there remains much to be learned before effective treatments can be developed. Type III secretion mechanisms, the locus of enterocyte effacement and various toxins are all involved in the pathogenesis of the various diarrhoeagenic E. coli and may provide targets for future therapies. This review ...
A comparison of enteropathogenic and enterohaemorrhagic Escherichia coli pathogenesis
FEMS Microbiology Letters, 2006
This review covers enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC) infections, focusing on differences in their virulence factors and regulation. While Shiga-toxin expression from integrated bacteriophages sets EHEC apart from EPEC, EHEC infections often originate from asymptomatic carriage in ruminants whereas human EPEC are considered to be overt pathogens and more host-restricted. In part, these differences reflect variation in adhesin repertoire, type III-secreted effectors and the way in which these factors are regulated.
BMC microbiology, 2002
Enterohaemorrhagic Escherichia coli (EHEC) is considered to be common cause of haemorrhagic colitis (HC), thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome (HUS) in humans. In a previous paper, we have demonstrated that EHEC are commonly found in the intestines of livestock. Infections in humans are, in part, a consequence of consumption of undercooked meat or raw milk. Argentina has one of the highest records of HUS (300-400 cases/year; 22/100,000 children under 4 years of age). The aim of this work is to communicate the first isolation of O145:H-from cattle in this country and characterize the virulence cassette, providing useful information to evaluate the risk of foodborne transmission of this emergent non-O157:H7 serotype. EHEC O145:H- was isolated from cattle in an Argentinian feedlot. Pheno- and genotype of nine strains were characterized, corresponding to several virulence cassettes: VT2+eaeA+ Mp+ (n = 5), VT2+eaeA+ (n = 1), VT1+eaeA+ Mp+ (n = 2), and VT1+e...
COMMENTARY Open Access Treatment of enterohemorrhagic Escherichia coli
2013
Verotoxigenic Escherichia coli (VTEC) are a specialized group of E. coli that can cause severe colonic disease and renal failure. Their pathogenicity derives from virulence factors that enable the bacteria to colonize the colon and deliver extremely powerful toxins known as verotoxins (VT) or Shiga toxins (Stx) to the systemic circulation. The recent devastating E. coli O104:H4 epidemic in Europe has shown how helpless medical professionals are in terms of offering effective therapies. By examining the sources and distribution of these bacteria, and how they cause disease, we will be in a better position to prevent and treat the inevitable future cases of sporadic disease and victims of common source outbreaks. Due to the complexity of pathogenesis, it is likely a multitargeted approach is warranted. Developments in terms of these treatments are discussed.
Enterohemorrhagic Escherichia coli
Current Opinion in Microbiology, 1998
Escherichia co/i has been responsible for an increasing number of large food-borne outbreaks of bloody diarrhea and hemolytic uremic syndrome. Recent developments in our understanding of the pathogenesis of disease due to enterhemorrhagic E. co/i include the description of a pathogenicity island, a type Ill secretion system and potential plasmid-encoded virulence factors. Recent developments in our understanding of the epidemiology include a recognition of a widening spectrum of vehicles.
Enteropathogenic and enterohaemorrhagic Escherichia coli and diarrhoea
Current Opinion in Infectious Diseases, 2000
Enteropathogenic and enterohaemorrhagic Escherichia coli are important causes of bacterial gastroenteritis with the potential for progression to more serious syndromes, especially in the case of enterohaemorrhagic E. coli. Consequently, recent developments in molecular epidemiology and treatment regimens have focused on enterohaemorrhagic E. coli, while the similar initial pathogenic mechanisms of both enterohaemorrhagic and enteropathogenic E. coli continue to be investigated in detail. The carriage of most E. coli virulence determinants on pathogenicity islands, plasmids or phages allows the rapid evolution of these pathotypes, which need to be monitored closely.