Deep sequencing reveals Campylobacter in commercial meat chickens less than 8 days old

Campylobacter from contaminated poultry meat is a major source of human gastroenteritis worldwide. To date, attempts to control this zoonotic infection with on-farm biosecurity measures have been inconsistent. A cornerstone of these efforts has been the detection of chicken infection with microbiological culture, which typically does not occur until birds are at least 21 days old. Using molecular methods for detecting Campylobacter presence, 16S microbiome analysis and deep sequencing of the Campylobacter porA gene, Campylobacter can be identified at very low levels in most or all flocks fewer than 8 days old. These young chicks exhibit a much greater diversity of porA types than older birds testing positive for Campylobacter by culture or qPCR. This suggests that, as the bacteria multiply sufficiently to be detected by culture methods, one or two strains, as indicated by porA type, dominate the infection. The findings that (i) most young chicks carry some Campylobacter and (ii) not all flocks become Campylobacter positive by culture, suggests that efforts to control infection should concentrate on how to maintain Campylobacter at low levels by the prevention of the overgrowth of single strains, which ultimately leads to the contamination of food.