A comprehensive risk factor analysis of Escherichia coli disease in the piggery environment.

Abstract

Enterotoxigenic Escherichia coli (ETEC) disease in pre- and post-weaned piglets has been identified by the Australian pork industry as an important issue affecting Australian pig producers. ETEC impacts young piglets causing a substantial health and economic burden. To date, the majority of research in Australia has focused on analysing clinical samples and characterising ETEC however, less is known about the underlying causes of ETEC outbreaks. A snap-shot survey to identify key host, pathogen, management and environmental factors contributing to ETEC disease in piglets was conducted after recruiting 22 pig producers located across southeastern Australia to participate. Information was collected via questionnaires and faecal samples. This data was obtained from each of the survey farms to determine the impacts of ETEC disease on pre- and post-weaned piglets. A forwards step-wise regression analysis identified recent disease events (within the herd in the last 12 months) and the presence of bedding to be statistically associated with the risk of post-weaning diarrhoea. Antimicrobial susceptibility screening of E. coli isolates revealed 6.1% (20/325) resistance to third-generation cephalosporins (3GC), further genetic analysis identified six different extended spectrum β-lactamase genes, blaCTX-M-1, -14, -15, -27, blaSHV-12 and blaCMY-2–like, four of which have not been previously reported in Australian pigs. The prevalence of 3GC resistance was higher in non-pathogenic (non-ETEC) isolates than those from clinically normal (non-diarrhoeal) samples. Developing resistance surveillance programs in pigs should include sampling of healthy pigs and their environment. An understanding of the interaction between humans, pigs and the environment using a One Health approach could assist in informing strategies to prevent and control ETEC disease and emerging resistance.