Pre- and post-weaning scours in southeastern Australia: A survey of 22 commercial pig herds and characterisation of Escherichia coli isolates

Abstract

Diarrhoeal diseases in piglets caused by Escherichia coli are responsible for substantial losses each year in the Australian pig industry. A cross-sectional survey was conducted (September 2013–May 2014) across 22 commercial pig herds located in southeastern Australia: NSW (n = 9); VIC (n = 10); and SA (n = 3), to estimate the prevalence of E. coli associated diarrhoea in pre- and post-weaned piglets and to identify key risk factors associated with E. coli disease. A questionnaire on management and husbandry practices was included. Faecal samples (n = 50 from each herd) were tested for the presence of β-haemolytic E. coli. Species level identification was confirmed by matrix-assisted laser desorption / ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). ETEC virulence and enterotoxin genes (F4, F5, F6, F18, F41, STa, STb and LT) were screened for by multiplex PCR. This study assessed 60 potential risk factors for E. coli disease in post-weaned piglets, with 2 key factors–recent disease events and the presence of bedding, statistically associated with the presence of post-weaning scours. The prevalence of diarrhea in pre-weaned pens was 17% (16/93), compared with 24% (24/102) in post-weaned pens. The most prevalent β-haemolytic ETEC genes were F18 (32%) and STb (32%) but isolates were more likely to contain F4:STb (11 of 22 herds, 23%), than F18:STb (5 of 22 herds, 6%). These findings indicate that recent disease events that have occurred within the last 12 months, and by the use of bedding or not maintaining fresh bedding can have significant impacts on piglet diarrhoea.

Antibiotic resistant Escherichia coli in southeastern Australian pig herds and implications for surveillance

“…Sampling of pigs in this study has been described previously (Van Breda, Dhungyel, Ginn, Iredell, & Ward, ). In brief, a cross‐sectional survey of 22 commercial herds located in southeastern Australia (Victoria, n = 10; New South Wales, n = 9; and South Australia, n = 3) was conducted between September 2013 and May 2014.…”

“…During collection, the samples were categorized as clinical (scours) or non‐clinical (normal) based on a faecal consistency score developed by Pedersen and Toft () with slight modifications (Van Breda et al., ). Pens were categorized as diarrhoea positive pens based on the collection of one or more diarrhoea samples (Van Breda et al., ). Up to 10 samples from pre‐weaned piglet pens and 40 from post‐weaned piglet pens, a total of 1,105 faecal samples were collected.…”

“…The number of pigs in pens sampled ranged from 10 to 1,000 (the average was 236). If there were 20 or less piglets in a pen, then five samples were collected from the pen (Van Breda et al., ). If there were >20 piglets in a pen, then 10 samples were collected per pen (Van Breda et al., ).…”

“…If there were 20 or less piglets in a pen, then five samples were collected from the pen (Van Breda et al., ). If there were >20 piglets in a pen, then 10 samples were collected per pen (Van Breda et al., ). A total of 195 pens (93 pre‐ and 102 post‐weaned) were sampled across 22 pig herds.…”

“…A total of 195 pens (93 pre‐ and 102 post‐weaned) were sampled across 22 pig herds. Faecal samples (approximately 2 g) from individual faecal pats at separate collection points within the pen were transferred into sterile 5‐ml tubes (Van Breda et al., ).…”