Host genes affect intestinal colonisation of newly hatched chickens by Campylobacter jejuni

Campylobacter jejuni is the leading cause of food-borne gastro-enteritis and infection can be followed by severe clinical complications, such as the autoimmune neuropathy Guillain–Barré syndrome. Poultry meat is considered to be a common source of infection, with most flocks infected from 2 to 3 weeks of age. We have examined the effect of host genetics on the colonisation levels of C. jejuni in chickens. Chicks from different inbred lines were challenged with 10⁷ to 10⁸ cfu of C. jejuni 14N or C. jejuni 81–176 on the day of hatch and levels of bacterial colonisation measured over a period of 2–3 weeks. We consistently observed a 10- to 100-fold difference between four inbred lines in the number of C. jejuni organisms present in the cloaca or in the caeca, with the greatest differences detected between line N, which carried relatively high bacterial levels, and line 6₁, which carried relatively low numbers of bacteria. Amongst the four lines studied, major histocompatibility complex did not appear to be a major factor in determining the resistance. The difference in numbers of cloacal bacteria was observed as soon as 24 h after challenge and was still present at the end of the experiment. Lines N and 6₁ were chosen to analyse the mode of inheritance of the genetic differences in response to this infection. Challenge of progeny from reciprocal (N×6₁) and (6₁×N) F1 crosses and from (N×6₁) F1×N backcrosses with C. jejuni 14N revealed that the difference in bacterial numbers was inherited in a manner consistent with the resistance (low bacterial numbers) controlled by a single autosomal dominant locus. These data suggest that it might be possible to identify the genes responsible by genetic mapping and candidate gene analysis.