Campylobacter jejuni and Campylobacter coli

Abstract

Definition of the disease: Campylobacter jejuni and C. coli can colonise the intestinal tract of most mammals and birds and are the most frequently isolated Campylobacter species in humans with gastro-enteritis. Transmission from animals to humans is mainly through consumption and handling of animal food products but also direct contact with colonised animals may contribute to human campylobacteriosis. This chapter focuses on C. jejuni and C. coli in primary livestock production with regard to food safety. Description of the disease: Campylobacter jejuni and C. coli do not cause clinical disease in adult animals except for sporadic cases of abortion in ruminants and very rare cases of hepatitis in ostriches. The faecal contamination of meat (especially poultry meat) during processing is considered to be a major source of human food-borne disease. In humans, extraintestinal infections, including bacteraemia, can occur and some sequelae of infection, such as polyneuropathies, though rare, can be serious. Identification of the agent: In mammals and birds, detection of intestinal colonisation is based on the isolation of the organism from faeces, rectal swabs and/or caecal contents. Campylobacter jejuni and C. coli are thermophilic, Gram-negative, highly motile bacteria that, for optimal growth, require microaerobic environment and incubation temperatures of 37–42°C. Agar media containing selective antibiotics are required to isolate these bacteria from faecal/intestinal samples. Alternatively, their high motility can be exploited using filtration techniques for isolation. Enrichment techniques to detect intestinal colonisation are not routinely used. Preliminary confirmation of isolates can be made by light microscopy. The organisms in the log growth phase are short and Sshaped in appearance, while coccoid forms predominate in older cultures. Under phase-contrast microscopy the organisms have a characteristic rapid corkscrew-like motility. Phenotypic identification is based on reactions under different growth conditions. Biochemical and molecular tests can be used to confirm various Campylobacter species. Polymerase chain reaction assays also can be used for the direct detection of C. jejuni and C. coli. Serological tests: serological assays are not routinely in use for the detection of C. jejuni/C. coli colonisation. Requirements for vaccines and diagnostic biologicals: There are no effective vaccines available for the prevention of enteric Campylobacter infections in birds or mammals.