MOLECULAR CHARACTERIZATION AND GASTROINTESTINAL TRACT ECOLOGY OF COMMENSAL HUMAN FOOD-BORNE BACTERIAL PATHOGENS IN THE CHICKEN
Location: Poultry Microbiological Safety Research
Title: Campylobacter species occurrence within internal organs and tissues of commercial caged Leghorn laying hens
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 2009
Publication Date: November 1, 2009
Citation: Cox Jr, N.A., Richardson, L.J., Buhr, R.J., Cray, P.J. 2009. Campylobacter spcies occurrence within internal organs and tissues of commercial caged Leghorn laying hens. Poultry Science. 88(1):2449-2456.
Interpretive Summary: Based on surveys by public health authorities in industrialized countries and available epidemiological information, table eggs are not currently regarded as a significant vehicle of food-borne Campylobacter infection for consumers. Therefore, the ecology of Campylobacter spp. within commercial caged laying hens has not been completely investigated due to the low rate of Campylobacter outbreaks associated with eggs. The purposes of conducting this study were to determine Campylobacter spp. prevalence in reproductive tracts, lymphoid organs, liver/gallbladder and ceca of commercial caged Leghorn laying hens, determine the species present within these sites, and antimicrobial resistance profile of the isolates. Campylobacter spp. presence within organs and tissues of Leghorn hens was similar to that found in other poultry even after several months in a caged environment. A high prevalence of C. jejuni and C. coli was determined in the flocks evaluated from commercial laying operations with tetracycline resistance observed in a few of the isolates and the majority of the isolates being pan-susceptible. The study revealed the dynamic nature of Campylobacter spp. and the importance to further understand Campylobacter ecology and mechanisms used to persist in poultry. Campylobacter spp. persist in organs, ovarian follicles, reproductive tissue and ceca of laying hens even when the major part of their life was spent in cages.
Campylobacter spp. are frequently present in the intestinal tract and internal tissues of broiler breeder and broiler chickens. Campylobacter spp. ecology in commercial Leghorn laying hens has not been extensively studied. The objectives of the current study were to determine 1) Campylobacter spp. presence in the reproductive tract, lymphoid organs, liver/gallbladder and ceca of commercial Leghorn laying hens, 2) species of Campylobacter present, and 3) antimicrobial resistance pattern of Campylobacter isolates. In study 1, three flocks ranging from 94 to 105 wk-of-age were sampled from a commercial laying complex. In study 2, two flocks, 82 and 84 wk-of-age were sampled from a separate complex. Hens were euthanized, de-feathered, aseptically necropsied, and the spleen, liver/gallbladder, ovarian follicles, upper (infundibulum, magnum, and isthmus) and lower (shell gland and vagina) reproductive tracts were aseptically removed prior to the ceca. Samples were packed on ice and transported to the laboratory for evaluation. For speciation, a standard BAX® real-time PCR method was used while susceptibility testing was performed using NCCLSI standards and recommended quality control organisms. Isolates were examined for susceptibility using a semi-automated testing system (Sensititre™) to the following nine antimicrobials: azithromycin, clindamycin, ciprofloxacin, erythromycin, florfenicol, gentamicin, nalidixic acid, telithromycin, and tetracycline. In study 1, the isolation rate was 13, 67, 53, 3, 13, and 57% from the ovarian follicles, lower reproductive tract, upper reproductive tract, spleen, liver/gallbladder, and ceca, respectively. In study 2, the isolation rate was 17, 43, 33, 20, 17, and 73% from the ovarian follicles, lower reproductive tract, upper reproductive tract, spleen, liver/gallbladder, and ceca, respectively. Overall, 50% of isolates were C. jejuni, 49% C. coli, and 1% C. lari. In study 1, all of the isolates were pan susceptible. In study 2, 37% of the isolates were resistant to tetracycline. Commercial table egg laying hens housed in colony cages on wire floors have diverse Campylobacter spp. recovered from different tissues that do not display resistance to a broad range of antimicrobials.