Waterborne Escherichia coli O157

138

In response to reports that the contamination of food can occur during the on-farm primary phase of food production, we report data that describes a possible cost-effective intervention measure. The effect of time before soil incorporation of livestock wastes spread to land on the rate of decline of zoonotic agents present in the waste was investigated. Fresh livestock wastes were inoculated with laboratory-cultured Salmonella, Listeria, and Campylobacter spp. and Escherichia coli O157 before they were spead onto soil. Incorporation of the spread wastes was either immediate, delayed for 1 week, or did not occur at all. Bacterial decline was monitored over time and found to be significantly more rapid for all waste types when they were left on the soil surface. There were no significant differences in initial bacterial decline rates when wastes were spread in summer or winter. Our results indicate that not incorporating contaminated livestock wastes into soil is a potential intervention measure that may help to limit the spread of zoonotic agents further up the food chain. The implications of these findings are discussed in relation to current advice for livestock waste disposal.Food can become contaminated with pathogenic microorganisms at all stages of manufacture and processing (13). However, there is a recognized potential for the on-farm transfer of pathogens to food during primary production (32). Livestock infected with zoonotic agents can excrete pathogens into their feces, and animal wastes have been implicated as a source of infection in a number of cases of human food-borne illness (2, 7). Since livestock wastes are routinely disposed of by spreading to agricultural land used for food production, the practice of waste spreading is an obvious consideration for any integrated pathogen-spread prevention-control strategy (5,17,18).Over the last decade, there has been an increase in the awareness of British farmers on the best practices for storage and disposal of livestock wastes (33). The publication of specific management guidance (26, 27) was driven largely by the need to control chemical pollution from wastes, including nitrate contamination of watercourses and airborne ammonia emissions (35). The effects of these chemical pollutants are immediate and obvious and overshadow more subtle environmental damage such as the dissemination of bacterial pathogens. Evaluation of current guidance, which has been targeted toward the control of chemical pollutants, suggested that it may increase the length of time that pathogens present in the waste could survive in the environment (18). Of particular concern is a move toward immediate solid waste incorporation and band spreading or direct injection of liquid wastes into soil. Such practices are likely to decrease the rate of waste drying, the levels of UV irradiation, and the daily range of temperatures experienced by pathogens present in the waste, potentially extending their survival (6). However, there is currently no experimentally derived information that sup...

Section: Vol 70 2004 Pathogen Decline In Livestock Wastes Spread Tomentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of Length of Time before Incorporation on Survival of Pathogenic Bacteria Present in Livestock Wastes Applied to Agricultural Soil

Hutchison¹,

Walters²,

Moore³

et al. 2004

138

“…Consequently, the confirmation of a presumptive causative agent involved in an outbreak is not always achieved (5). Moreover, the detection of non-O157 STEC strains is particularly difficult due to the lack of common phenotypic characteristics such as those presented by typical E. coli O157:H7 strains (delayed fermentation of sorbitol and the absence of ␤-glucuronidase activity).…”

mentioning

confidence: 99%

Prevalence of the stx ₂ Gene in Coliform Populations from Aquatic Environments

García-Aljaro

Muniesa

Jofre

et al. 2004

Shiga toxin-producing Escherichia coli strains are human pathogens linked to hemorrhagic colitis and hemolytic uremic syndrome. The major virulence factors of these strains are Shiga toxins Stx1 and Stx2. The majority of the genes coding for these toxins are borne by bacteriophages. Free Stx2-encoding bacteriophages have been found in aquatic environments, but there is limited information about the lysogenic strains and bacteria present in the environment that are susceptible to phage infection. The aim of this work was to study the prevalence and the distribution of the stx 2 gene in coliform bacteria in sewage samples of different origins. The presence of the stx 2 gene was monitored every 2 weeks over a 1-year period in a municipal sewage treatment plant. A mean value of 10 2 genes/ml was observed without significant variation during the study period. This concentration was of the same order of magnitude in raw municipal sewage of various origins and in animal wastewater from several slaughterhouses. A total of 138 strains carrying the stx 2 gene were isolated by colony hybridization. This procedure detected approximately 1 gene-carrying colony per 1,000 fecal coliform colonies in municipal sewage and around 1 gene-carrying colony per 100 fecal coliform colonies in animal wastewaters. Most of the isolates belonged to E. coli serotypes other than E. coli O157, suggesting a low prevalence of strains of this serotype carrying the stx 2 gene in the wastewater studied.

“…Studies have indicated that E. coli can survive for extended periods in manure and water (7,11). We have demonstrated that lettuce grown in soil containing contaminated manure or irrigated with contaminated water results in contamination of the edible portion of the lettuce plant.…”

mentioning

confidence: 99%

Transmission of Escherichia coli O157:H7 from Contaminated Manure and Irrigation Water to Lettuce Plant Tissue and Its Subsequent Internalization

Solomon

Yaron

Matthews

2002

615

422

The transmission of Escherichia coli O157:H7 from manure-contaminated soil and irrigation water to lettuce plants was demonstrated using laser scanning confocal microscopy, epifluorescence microscopy, and recovery of viable cells from the inner tissues of plants. E. coli O157:H7 migrated to internal locations in plant tissue and was thus protected from the action of sanitizing agents by virtue of its inaccessibility. Experiments demonstrate that E. coli O157:H7 can enter the lettuce plant through the root system and migrate throughout the edible portion of the plant.