Leaching of Escherichia coli O157:H7 in Diverse Soils under Various Agricultural Management Practices

Abstract

Application of animal manures to soil as crop fertilizers is an important means for recycling the nitrogen and phosphorus which the manures contain. Animal manures also contain bacteria, including many types of pathogens. Manure pathogen levels depend on the source animal, the animal's state of health, and how the manure was stored or treated before use. Rainfall may result in pathogen spread into soil by runoff from stored or unincorporated manure or by leaching through the soil profile. Steady rainfall consisting of 16.5 mm h ؊1 was applied to 100-mm disturbed soil cores that were treated with manure and inoculated with Escherichia coli O157:H7 strain B6914. The level of B6914 in leachate was near the inoculum level each hour for 8 h, as was the level of B6914 at several soil depths after 24 h, indicating that there was a high rate of growth. Bacterial movement through three different types of soil was then compared by using disturbed (tilled) and intact (no-till) soil cores and less intense rainfall consisting of 25.4 mm on 4 consecutive days and then four more times over a 17-day period. Total B6914 levels exceeded the inoculum levels for all treatments except intact clay loam cores. B6914 levels in daily leachate samples decreased sharply with time, although the levels were more constant when intact sandy loam cores were used. The presence of manure often increased total B6914 leachate and soil levels in intact cores but had the opposite effect on disturbed soil cores. Ammonia and nitrate levels correlated with B6914 and total coliform levels in leachate. We concluded that tillage practice, soil type, and method of pathogen delivery affect but do not prevent vertical E. coli O157:H7 and coliform transport in soil and that soluble nitrogen may enhance transport.

Impacts of Long-Term Irrigation of Domestic Treated Wastewater on Soil Biogeochemistry and Bacterial Community Structure

“…In fact, some of the microorganisms identified from the irrigated pivots are likely native to the wastewater holding tanks where TWW is stored prior to being used in irrigation and so were likely transported into the soils from the wastewater. This is a critical point, given that the survival of wastewater microorganisms under environmental conditions can vary from a few days to 3 months (92,93). However, a detailed examination of our data clearly shows that most of the predominant bacteria from the irrigated soils are, in fact, native to soils rather than wastewater, with the exception of only cyanobacteria (Fig.…”

Physicochemical and microbiological quality of raspberries (Rubus idaeus) treated with different doses of gamma irradiation

“…that are usually present in the irrigation water, manure in the soil or fertilizer, or due to improper handling of the product (GANGLIARDI; KARNS, 2000).…”

Advances and Trends in Organic Fruit and Vegetable Farming Research

“…As some enteric pathogens, such as Salmonella typhimurium, shiga toxin-producing E. coli, and L. monocytogenes, are able to survive on the soil surface and in the soil for a long time-even over several months (Faust 1982;Pell 1997;Gagliardi and Karns 2000;Jamieson et al 2002;Islam et al 2004aIslam et al ,b, 2005Mukherjee et al 2006;Diez-Gonzalez 2007)-there is an obvious risk for transmission to a vegetable or fruit crop from preceding pasture. For these reasons, Köpke et al (2007) recommended not to grow vegetables for 12 months following pasture.…”