Experimental infection of specific pathogen-free pigs with Campylobacter: Excretion in faeces and transmission to non-inoculated pigs

Campylobacter species are leading agents of human bacterial gastroenteritis and consumption of food of animal origin is a major source of infection. Although pigs are known to frequently exhibit high counts of Campylobacter in their faeces, more information is needed about the dynamics of this excretion. An experimental trial was conducted to evaluate the faecal excretion of Campylobacter by 7-week-old specific pathogen-free piglets inoculated per os with three Campylobacter strains (one C. coli isolated from a pig, one C. coli and one C. jejuni from chickens) alone or simultaneously (5 × 107 CFU/strain). Non-inoculated pigs were housed in adjacent pens. Pigs were monitored for 80 days for clinical signs and by bacteriological analysis of faeces. Pigs inoculated with porcine C. coli or with a mix of the three strains excreted from 103 to 106 CFU/g of faeces with a slight decrease at the end of the trial. Animals inoculated with poultry C. coli or C. jejuni strain excreted a lower quantity and some of them stopped excreting. At the end of the trial, only C. coli was detected in the faeces of pigs inoculated simultaneously with the three bacteria. Moreover, the transmission of Campylobacter was noticed between pens for the two C. coli strains and all the neighbouring animals became shedders with a level of excretion similar to the inoculated pigs. Intermittence in the Campylobacter excretion was also observed. Finally, our study highlighted a host preference of Campylobacter, namely C. coli seems to have a higher colonization potential for pigs than C. jejuni.