Colonization of day-old broiler chicks with Campylobacter coli through different inoculation routes

Authors: Cosby, Douglas; Cox Jr, Nelson; HARRISON, MARK - University Of Georgia; Berrang, Mark; WILSON, JEANNA - University Of Georgia

Submitted to: Journal of Veterinary Medicine and Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2018
Publication Date: 7/29/2018
Citation: Cosby, D.E., Cox Jr, N.A., Harrison, M.A., Berrang, M.E., Wilson, J.L. 2018. Colonization of day-old broilers with gentamicin resistant Campylobacter coli following challenge via different inoculation routes. Journal of Veterinary Medicine and Research. 4(7):1096.

Interpretive Summary: Campylbacteriosis continues to be a human illness associated with consumption of poultry and poultry products. The routes of entry of Campylobacter species into the young chicks has not been clearly defined due to the lack of a marker strain of Campylobacter. With the addition of a gentamycin resistant Campylobacter coli to our research tools we are able to look at various body openings of the chick to determine the most efficient route of entry into the young bird. Our findings will help us develop effective intervention strategies to lessen the impact of campylobacteriosis in human illness.

Technical Abstract: Newly hatched broiler chicks may be exposed to Campylobacter from various sources in the hatchery and grow-out environments. Chicks may come in contact with Campylobacter in the air or in the droppings of other birds which chicks may eat or sit on. It is not clear how airborne, cloacal and oral exposure to Campylobacter may affect subsequent cecal colonization. In this study, a marker strain of Campylobacter coli, naturally gentamicin resistant [CcGR], was introduced into 585 day-of-hatch chicks through each of four body openings [mouth, nasal passage, eye and cloaca] to simulate oral, cloacal and airborne exposure. Campylobacter coliGR was introduced by each route of exposure at three different inoculum levels [approximately 2 x 10e1, 2 x 10e2 and 2 x 10e3 colony forming units (cfu)/bird]. All chicks were humanely euthanized 7d post inoculation, ceca were aseptically removed and sampled for the presence and numbers of CcGR by serial dilution onto Campy-cefex agar plates with 200 ppm gentamicin added. Three replications were conducted [n=225, n=225 and n=135 for experiments 1, 2 and 3 respectively]. All routes of exposure that were tested resulted in cecal colonization of 7 d old broilers. The nasal passage produced the lowest level of cecal colonization requiring higher inoculum levels of CcGR for colonization. These data suggest that CcGR can readily colonize the ceca of day-of-hatch broiler chicks when exposed by mouth, cloaca, or breathing/blinking in airborne cells. Therefore, multiple intervention strategies may be required to interrupt exposure and/or colonization of young broilers by Campylobacter.