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a.p. williams, l.m. avery, k. killham and d.l. jones. 2005.To compare the persistence ofEscherichia coliO157 on a variety of common faecally contaminated farmyard material surfaces (wood and steel) under different moisture and temperature regimes.Samples of field-conditioned farmyard materials (galvanized steel and wood) were cut into pieces and contaminated with fresh cattle faeces inoculated with nontoxigenicE. coliO157 (strain 3704). Thereafter, they were stored at four different environmental conditions; with temperature (5 and 20°C) and moisture (moist or dry) as variables. Transfer of the pathogen to hands from the surfaces was also evaluated.Escherichia coliO157 numbers declined over time on all surfaces albeit at different rates according to the sample material and environmental conditions. Persistence was greatest on moist wood samples under cooler temperatures with large population numbers remaining after 28 days. Desiccation of surfaces resulted in a more rapid decline inE. coliO157 populations under both temperature regimes. Substantial numbers of colonies may also potentially be transferred to human hands from the surfaces during brief contact.When environmental conditions are favourable,E. coliO157 may persist for considerable times on a range of surfaces. However, when exposed to higher temperatures and dehydration, survival is notably decreased. Overall, bacterial persistence was significantly greater on wood samples relative to steel.Escherichia coliO157 is a prevalent pathogen, common in ruminant faeces. Contact with contaminated faeces may lead to human infection, resulting in possible severe illness. Although our study used only one strain of bacteria, our findings indicates thatE. coliO157 has the potential to persist for long periods of time on gates, stiles and other farmyard surfaces under a range of environmental conditions. These farmyard surfaces therefore pose a potential infection pathway particularly where there is a high risk of direct human contact (e.g. child petting zoos, open farms). [ABSTRACT FROM AUTHOR]

Abstract: Contamination of watercourses with fecal matter represents a significant risk to public health due to the associated risk from human pathogens (e.g. Escherichia coli O157, norovirus). In addition, water contamination may also perpetuate the re-infection cycle of human pathogens within domesticated and wild animal populations. While diffuse pollution from agricultural fields has been identified as a major source of these pathogens, the relationship between livestock grazing intensity and subsequent pathogen persistence in water is not well established. Our aim was to critically evaluate the importance of land use management on the activity of E. coli O157 in freshwaters collected from a livestock dominated catchment in the UK. We inoculated replicate batches of both filter-sterilised and non-sterile freshwaters with a chromosomally lux-marked E. coli O157 and monitored pathogen survival and activity over a 5 d period. Our results indicate that the greatest risk for pathogens entering freshwater is probably associated with high intensity livestock areas, although their subsequent survival is greatest in waters from low intensity livestock areas. We ascribe this enhanced persistence in the latter to reduced competition and predation within these aquatic environments. These results have serious implications for the reliability of pathogen risk exposure maps which are based on grazing intensity alone. [Copyright &y& Elsevier]