Prevalence and clonal nature of Escherichia coli O157:H7 on dairy farms in Wisconsin

Aims: To provide molecular epidemiological evidence of avian transmission of Escherichia coli O157:H7 between dairy farms in Ohio, this study was designed to identify genetic relatedness between isolates originating from bovine faecal samples and intestinal contents of European starlings captured on these farms. Methods and Results: During a three‐year period (2007–2009), cattle (n = 9000) and starlings (n = 430) on 150 different dairy farms in northern Ohio were sampled for the presence of E. coli O157:H7. Isolates were subjected to multiple‐locus variable‐nucleotide tandem repeat analysis (MLVA). Distinct allelic groups were identified on most farms; however, isolates clustering into three MLVA groups originated from both cattle and birds on different farms. Conclusions: Sharing of indistinguishable epidemiologically linked E. coli O157 MLVA subtypes between starlings and cattle on different farms supports the hypothesis that these birds contribute to the transmission of E. coli O157:H7 between dairy farms. Significance and Impact of Study: A continued need exists to identify and to improve preharvest measures for controlling E. coli O157:H7. Controlling wildlife intrusion, particularly European starlings, on livestock operations, may be an important strategy for reducing dissemination of E. coli O157:H7 between farms and thereby potentially decreasing the on‐farm prevalence of E. coli O157:H7 and enhancing the safety of the food supply.

Section: Discussionsupporting

confidence: 94%

Multiple-locus variable-nucleotide tandem repeat subtype analysis implicates European starlings as biological vectors for Escherichia coli O157:H7 in Ohio, USA

Williams

Pearl

LeJeune

2011

“…More recent examination of the strains by pulsed field gel electrophoresis indicated that the colonizing strain probably remained the same throughout the study. This is in contrast to other studies that have shown that the strain present in a herd changed frequently (Faith et al 1996).…”

Section: Unpasteurized Milk As a Source Of Infection In 1993contrasting

confidence: 99%

Sources of Escherichia coli O157 and experiences over the past 15 years in Sheffield, UK

Chapman¹

2000

SUMMARY In the first documented outbreak of HC caused by Escherichia coli O157, which occurred in the North‐west USA in 1982, there was a strong association between infection and prior consumption of ground beef from a chain of fast food restaurants. Foods of bovine origin, including beef, milk and dairy products, have since been implicated in many outbreaks of infection world‐wide. Investigations during the course of outbreaks, or at random, have shown that cattle are a major reservoir of E. coli O157. E. coli O157 was isolated from cattle at slaughter in Sheffield in 1987, this being the first isolation from cattle in the UK. Following a cluster of cases in May/June 1992, an abattoir study showed the organism to be present in 4% of cattle at slaughter and on up to a third of carcasses from rectal swab‐positive animals. E. coli O157 was isolated from a food source (unpasteurized milk), for the first time in the UK, in Sheffield in May 1993. During surveillance in 1995–6, E. coli O157 was isolated from 157% of cattle, with a monthly prevalence which varied from 5 to 37%. E. coli O157 was also isolated from 22% of sheep. During surveillance in 1996, E. coli O157 was isolated from 59% of samples of lamb products and from 15% of samples of beef products, despite the prevalence in cattle being much higher than in sheep. Work is in progress to try to explain this higher prevalence in lamb products. During 1997 in Sheffield, the only cases of E. coli O157 for which a confirmed source was established were associated with direct animal contact on farm visits. During on‐farm investigations of these cases, E. coli O157 was isolated from faecal samples from adult cattle, calves, three different breeds of sheep, two different breeds of pigs, goats and a pony.

“…Escherichia coli O157:H7 and Salm. Typhimurium are important food-borne pathogens that are known to be widely present in the gastrointestinal tract of ruminant animals (Wells et al 1991;Zschöck et al 2000;Wells et al 2001;Laven et al 2003) and are usually shed asymptomatically in faeces (Losinger et al 1995;Faith et al 1996;Omisakin et al 2003;Cummings et al 2009). Although enteric food-borne pathogenic bacteria such as E. coli O157:H7 and Salm.…”

Section: Introductionmentioning

confidence: 99%

Survival ofEscherichia coliO157:H7 andSalmonella entericaserovar Typhimurium in manure and manure-amended soil under tropical climatic conditions in Sub-Saharan Africa

Ongeng

Muyanja

Geeraerd

et al. 2011

Aims: To establish the fate of Escherichia coli O157:H7 and Salmonella Typhimurium in manure and manure‐amended agricultural soils under tropical conditions in Sub‐Saharan Africa. Methods and Results: Survival of nonvirulent E. coli O157:H7 and Salm. Typhimurium at 4 and 7 log CFU g−1 in manure and manure‐amended soil maintained at ≥80% r.h. or exposed to exclusive field or screen house conditions was determined in the Central Agro‐Ecological Zone of Uganda. Maintaining the matrices at high moisture level promoted the persistence of high‐density inocula and enhanced the decline of low‐density inocula in the screen house, but moisture condition did not affect survival in the field. The large majority of the survival kinetics displayed complex patterns corresponding to the Double Weibull model. The two enteric bacteria survived longer in manure‐amended soil than in manure. The 7 log CFU g−1E. coli O157:H7 and Salm. Typhimurium survived for 49–84 and 63–98 days, while at 4 log CFU g−1, persistence was 21–28 and 35–42 days, respectively. Conclusions: Under tropical conditions, E. coli O157:H7 and Salm. Typhimurium persisted for 4 and 6 weeks at low inoculum density and for 12 and 14 weeks at high inoculum density, respectively. Significance and Impact of the Study: Persistence in the tropics was (i) mostly shorter than previously observed in temperate regions thus suggesting that biophysical conditions in the tropics might be more detrimental to enteric bacteria than in temperate environments; (ii) inconsistent with published data isothermally determined previously hence indicating the irrelevance of single point isothermal data to estimate survival under dynamic temperature conditions.