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Title: Campylobacter multi-locus sequence types and antimicrobial susceptibility of broiler cecal isolates: a two year study of 143 commercial flocks

Author
item LADELY, SCOTT - Former ARS Employee
item Berrang, Mark
item Meinersmann, Richard - Rick
item Cox Jr, Nelson

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2017
Publication Date: 5/1/2017
Citation: Ladely, S., Berrang, M.E., Meinersmann, R.J., Cox Jr, N.A. 2017. Campylobacter multi-locus sequence types and antimicrobial susceptibility of broiler cecal isolates: a two year study of 143 commercial flocks. Journal of Food Safety. doi:10.1111/jfs.12366.

Interpretive Summary: Campylobacter jejuni and coli are bacterial pathogen that cause human disease associated with chicken and chicken meat products. This is especially concerning when the organism is resistant to antimicrobial drugs. Campylobacter is naturally present in chicken gut and gut contents and can be found associated with broiler chickens at slaughter. It is useful to know how prevalent Campylobacter is among broiler flocks, how many subtypes of the organism we can expect and how likely it is to be resistant to antimicrobial drugs. We sampled the gut contents of broiler chickens from 143 flocks at commercial slaughter. Campylobacter was detected in broilers from 72 flocks. A total of 24 unique subtypes of Campylobacter were detected within 10 major types (clonal complexes). Some types were more likely than others to have antimicrobial resistance. Specifically, C. coli members of clonal complex 828 were more likely to be resistant to azithromycin, clindamycin, erythromycin, and gentamicin while members of clonal complex 48 were significantly more likely to be resistant to ciprofloxacin and nalidixic acid than were other Campylobacter isolated in this study. Overall, broiler chickens in Georgia can be expected to be colonized with Campylobacter. Campylobacter coli is more likely than C. jejuni to be resistant to antimicrobials and some subtypes have more antimicrobial resistance than others.

Technical Abstract: The objective of this study was to assess genetic diversity and antimicrobial susceptibility of Campylobacter jejuni and coli recovered from broiler ceca at slaughter. Ceca from one broiler were collected from the evisceration line in a commercial processing plant, once or twice weekly for two years (n=143). Campylobacter were cultured from the cecal contents and analyzed by whole genome sequencing, multi-locus sequence typing (MLST) and antimicrobial susceptibility testing. Seventy-two of 143 birds examined were positive for Campylobacter. A total of 24 MLST sequence-types (ST) were identified belonging to ten Campylobacter clonal complexes (CC). The Simpson’s Index of Diversity (SID) was 0.93 for STs and 0.68 for CCs. Three MLST clonal complexes, CC-353 (53.2%), CC-828 (17.7%), and CC-48 (11.4%) accounted for the majority of Campylobacter isolates recovered. Compared to all other clonal complexes, a significantly higher percentage (P<0.05) of C. coli isolates belonging to CC-828 complex were resistant to azithromycin, clindamycin, erythromycin, and gentamicin. CC-48 was significantly more resistant to ciprofloxacin and nalidixic acid than other CCs regardless of species. No isolates were resistant to florfenicol.