Options for the control of enterhaemorrhagic Escherichia coli in ruminants (original) (raw)
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REVIEW ARTICLE Options for the control of enterohaemorrhagic Escherichia coli in ruminants
2000
Enterohaemorrhagic Escherichia coli (EHEC) comprise an important group of zoonotic enteric pathogens. In humans, some EHEC infections result in bloody or non- bloody diarrhoea, which may be complicated by haem- orrhagic colitis and severe renal and neurological sequelae, including haemolytic uraemic syndrome (HUS). Ruminants are an important reservoir of EHEC and human infections are frequently associated with direct or indirect
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.
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.
Prevalence of enterohemorrhagic Escherichia coli O157: H7 in a survey of dairy herds
Applied and Environmental …, 1995
The prevalence of Escherichia coli O157:H7 in dairy herds is poorly understood, even though young dairy animals have been reported to be a host. From February to May 1993, 662 fecal samples from 50 control herds in 14 states, and from June to August 1993, 303 fecal samples from 14 case herds in 11 states were collected for isolation of E. coli O157:H7. Case herds were those in which E. coli O157:H7 was isolated from preweaned calves in a previous U.S. Department of Agriculture study, whereas control herds from which E. coli O157:H7 had not been isolated previously were randomly selected from the same states as case herds. Among the control herds, E. coli O157:H7 was isolated from 6 of 399 calves (1.5%) that were between 24 h old and the age of weaning and from 13 of 263 calves (4.9%) that were between the ages of weaning and 4 months. Eleven of 50 control herds (22%) were positive. Among the case herds, E. coli O157:H7 was isolated from 5 of 171 calves (2.9%) that were between 24 h old and the age of weaning and from 7 of 132 calves (5.3%) that were between the ages of weaning and 4 months. Seven of 14 case herds (50%) were positive. Sixteen of 31 isolates were obtained by direct plating, with populations ranging from 10 3 to 10 5 CFU/g. Fifteen of 31 isolates were isolated by enrichment only. Nineteen of the isolates produced both verocytotoxin 1 (VT-1) and VT-2, whereas 12 produced VT-2 only.
Advances in Animal and Veterinary Sciences, 2019
H ealth of the newborn calves is a matter of balance concerning the pathogens, immune system of the newborn animal, environment and management system. Infection in newborn calves is multifactorial in nature and it seems to be the result of interaction between different factors that may contribute to the buildup of infection including the immunological, nutritional, and environmental factors, (Hosein, 2018). Neonatal calf diarrhea is one of the most serious health problems in the livestock industry and an important cause of economic losses due to high morbidity and mortality rates, high treatment costs and low growth rate, (Al-Alo et al., 2018; Anderson et al., 2003; Bazeley, 2003). Diarrhea is the most important cause of losses in calves up to 30 days of age and still problematic, likely because of the multi-factorial nature of the disease, Gomez and Weese (2017). Difference between health and disease among new born calves is very often just a slight tip of a delicate balance that weighs calf and environmental factors with the pathogens to which the calf will be exposed. E. coli an important enteric pathogen of bovine neonates, is established in intestines shortly after the birth and remains throughout life. It has been incriminated as a major cause of diarrhea characterized by progressive dehydration and death that may occur depending on the age of the calf when scour started and the pathotypes of E. coli involved (Nguyen et al., 2011). Several E. coli serotypes, causing morbidity and mortality, have been isolated from calves suffering from diarrhea (Wani et al., 2003). E. coli pathotypes that are incriminated in neonatal calf diar-research Article Abstract | A total of 14 (30.43%) diarrheic calves of 1-4 weeks out of 46 calves kept under poor hygienic conditions in a dairy farm were suffering clinically from acute diarrhea. Diarrheic calves showed fever, diarrhea, dehydration, pneumonia recumbence and death of two calves. Thirteen (92.85 %) isolates of E. coli out of the 14 collected rectal swaps of diarrheic calves were identified on bacteriological and molecular basis. The results of the amplification of phoAgene using PCR revealed that all E. coli isolates showed positive result for the presence of phoAgene, thus confirming their identity as E. coli. All tested E. coli isolates were positive for intimin (eae) A, attaching and effacing gene (gene species specific) for E. coli (100%). No isolate had shiga toxin1 (stx1), shiga toxin 2 (stx2), hemolysin (hylA), and E. coli enterotoxin genes heat stable enterotoxin (st) and heat labile enterotoxin (lt). The obtained results indicate the possible participation of pathogenic E. coli in calf diarrhea. EPEC represented 100% of the tested E. coli strains obtained from diarrheic calves. The obtained results indicated that EPEC infection is a major health problem among calves and suggests the significance of poor hygiene measures in the investigated farm the possible participation of calves in the zoonotic transmission of pathogenic E. coli.
Applied and Environmental Microbiology, 2006
Cattle drinking water is a source of on-farm Escherichia coli O157:H7 transmission. The antimicrobial activities of disinfectants to control E. coli O157:H7 in on-farm drinking water are frequently neutralized by the presence of rumen content and manure that generally contaminate the drinking water. Different chemical treatments, including lactic acid, acidic calcium sulfate, chlorine, chlorine dioxide, hydrogen peroxide, caprylic acid, ozone, butyric acid, sodium benzoate, and competing E. coli, were tested individually or in combination for inactivation of E. coli O157:H7 in the presence of rumen content. Chlorine (5 ppm), ozone (22 to 24 ppm at 5°C), and competing E. coli treatment of water had minimal effects (<1 log CFU/ml reduction) on killing E. coli O157:H7 in the presence of rumen content at water-to-rumen content ratios of 50:1 (vol/wt) and lower. Four chemical-treatment combinations, including (i) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.05% caprylic acid (treatment A); (ii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.1% sodium benzoate (treatment B); (iii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.5% butyric acid (treatment C); and (iv) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 100 ppm chlorine dioxide (treatment D); were highly effective (>3 log CFU/ml reduction) at 21°C in killing E. coli O157:H7, O26:H11, and O111:NM in water heavily contaminated with rumen content (10:1 water/rumen content ratio [vol/wt]) or feces (20:1 water/feces ratio [vol/wt]). Among them, treatments A, B, and C killed >5 log CFU E. coli O157:H7, O26:H11, and O111:NM/ml within 30 min in water containing rumen content or feces, whereas treatment D inactivated approximately 3 to 4 log CFU/ml under the same conditions. Cattle given water containing treatment A or C or untreated water (control) ad libitum for two 7-day periods drank 15.2, 13.8, and 30.3 liters/day, respectively, and cattle given water containing 0.1% lactic acid plus 0.9% acidic calcium sulfate (pH 2.1) drank 18.6 liters/day. The amounts of water consumed for all water treatments were significantly different from that for the control, but there were no significant differences among the water treatments. Such treatments may best be applied periodically to drinking water troughs and then flushed, rather than being added continuously, to avoid reduced water consumption by cattle.