Prevalence of Shiga toxin ‐producing Escherichia coli in pasture‐based dairy herds

This study evaluated the prevalence and virulence status of O157:H7 and sixE. coli O ‐serogroups (O26, O103, O45, O145, O121, O111) in New Zealand dairy farms using molecular as well as culture‐based methods. Fresh farm dairy effluent (FDE) (n=36) and composite calf faeces (n=12) were collected over three samplings from 12 dairy farms. All seven target serogroups were detected t hrough molecular techniques. Of the 202 isolates which were serologically confirmed following traditional culturing and immunomagnetic separation (IMS), O103, O26, O45 and O121 were the most common serogroups, being found in 81%, 47%, 42%, 32% of the FDE and in 17%, 33%, 25%, 9% of the calf faeces, respectively. The majority (157/202) of the isolates were negative forstx andeae virulence genes. The prevalence of the seven target STEC was low, and only nine O26 isolates (4%) were recovered from four of the farms. The study has highlighted the need for improving the isolation of Top 7 STEC from thestx‐negative populations present in fresh dairy effluent and calf faeces.This article is protected by copyright. All rights reserved.
Source: Letters in Applied Microbiology - Category: Microbiology Authors: Tags: Original Article Source Type: research