Prevalence of Shiga toxin-producing Escherichia coli stx1, stx2, eaeA, and rfbE genes and survival of E. coli O157:H7 in manure from organic and low-input conventional dairy farms.

Manure samples were collected from 16 organic (ORG) and 9 low-input conventional (LIC) Dutch dairy farms during August and September 2004 to determine the prevalence of the STEC virulence genes stx(1) (encoding Shiga toxin 1), stx(2) (encoding Shiga toxin 2), and eaeA (encoding intimin), as well as the rfbE gene, which is specific for Escherichia coli O157. The rfbE gene was present at 52% of the farms. The prevalence of rfbE was higher at ORG farms (61%) than at LIC farms (36%), but this was not significant.

DGGE fragments oscillate with or counter to fluctuations in cultivable bacteria along wheat roots.

Previously, we showed that bacterial populations oscillate in response to a moving substrate source such as a root tip, resulting in moving wavelike distributions along roots. For this article, we investigated if bacterial communities fluctuate as a whole or if there is a succession in bacterial composition from peak to peak or within peaks. Rhizosphere microbial communities along roots of wheat Triticum aestivum L.

Effects of cattle feeding regimen and soil management type on the fate of Escherichia coli O157:H7 and salmonella enterica serovar typhimurium in manure, manure-amended soil, and lettuce.

Survival of the green fluorescent protein-transformed human pathogens Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium was studied in a laboratory-simulated lettuce production chain. Dairy cows were fed three different roughage types: high-digestible grass silage plus maize silage (6:4), low-digestible grass silage, and straw. Each was adjusted with supplemental concentrates to high and low crude protein levels.