Prevalence of Salmonella, Campylobacter and VTEC on pig farms

Four different pig farms were sampled for the prevalence of Salmonella, Campylobacter and verotoxigenic E. coli (VTEC). Pigs of different age groups and pigs of the same age were tested by taking rectal swabs. The farm environment was tested by examining overshoes, and the feed and drinking water in the pens. From a total of 215 rectal samples of individual pigs, 15 rectal samples taken from animals at the same farm were positive for Salmonella. The Salmonella status of the pigs at this farm differed from one age group to another. S. Typhimurium was isolated from all the positive rectal samples and S. Typhimurium and S. Schwarzengrund were isolated from the environment. On two other farms Salmonella was only present in the environment with S. London and S. Typhimurium as serotypes. The presence of Campylobacter was tested in 150 rectal swabs, 51 of these, spread over the four farms, turned out to be positive. At all four pig farms Campylobacter was isolated from the environment as well. All the strains were identified as Campylobacter coli by a species-specific PCR. To determine if pigs are a reservoir of VTEC a total of 289 samples were screened for the presence of VTEC and 54 strains were isolated that each carried one virulence gene. Thirty-one strains carried the vt2e variant of the vt2 gene wich causes the endema disease in young pigs, four strains harboured the hlyA gene and 19 the eaeA gene.