Experimental infection of weaned piglets with Campylobacter coli--excretion and translocation in a pig colonisation trial

Campylobacter (C.) is one of the most common food-borne pathogen causing bacterial enteric infections in humans. Consumption of meat and meat products that have been contaminated with Campylobacter are the major source of infection. Pigs are a natural reservoir of Campylobacter spp. with C. coli as the dominant species. Even though some studies focussed on transmission of C. coli in pig herds and the excretion in faeces, little is known about the colonisation and excretion dynamics of C. coli in a complex gut microbiota present in weaned piglets and the translocation to different tissues. Therefore, an experimental trial was conducted to evaluate the colonisation and translocation ability of the porcine strain C. coli 5981 in weaned pigs. Thus, ten 35 days old piglets were intragastrically inoculated with strain C. coli 5981 (7 x 10(7)CFU/animal) encoding resistances against erythromycin and neomycin. Faecal samples were taken and C. coli levels were enumerated over 28 days. All piglets were naturally colonised with C. coli before experimental inoculation, and excretion levels ranged from 10(4) to 10(7)CFU/g faeces. However, no strain showed resistances against the additional antimicrobials used. Excretion of C. coli 5981 was seen for all piglets seven days after inoculation and highest counts were detectable ten days after inoculation with 10(6)CFU/g faeces. Post-mortem, translocation and subsequent invasion of luminal C. coli was observed for gut tissues of the small intestine and for the gut associated lymphatic tissues, such as jejunal mesenteric lymph nodes and tonsils as well as for spleen and gall bladder. In conclusion, this pig colonisation trial offers the opportunity to study C. coli colonisation in weaned piglets using the porcine strain C. coli 5981 without the need for gnotobiotic or specific pathogen-free animals