Detection and antimicrobial resistance of Campylobacter spp. from retail chicken parts in the Southeastern U.S.: A molecular approach

ABSTRACT In the United States, contaminated poultry and meat products account for more than 70% of Campylobacter -related foodborne infections in humans. To isolate Campylobacter and conduct genomic analyses, 103 chicken parts were purchased from retail grocery stores located in the Southeastern U.S. Phenotypic antimicrobial susceptibility tests were performed using the National Antimicrobial Resistance Monitoring System broth microdilution method. The antimicrobial resistance genes and virulence factors of each isolate were also identified. Data were analyzed in R with Firth’s penalized logistic regression using the “logistf” package to determine the effect of chicken parts and production labels on the odds ratio of Campylobacter detection, with P < 0.05 and a 95% confidence interval. Post hoc pairwise comparisons were conducted using Fisher’s exact tests with the “emmeans” package. The overall prevalence of Campylobacter in chicken parts was 20% (21/103), with prevalence ranging from 8% in breast meat to 54% in wings. Moreover, the odds of Campylobacter detection in wings were 11 times (95% confidence intervals [CI]; 2.36–73.56) more likely than those in breast samples ( P = 0.00199). However, there were no significant differences ( P > 0.05) in the odds of Campylobacter detection among production labels. Among positive samples, 71% (15/21) of the isolates were identified as C. jejuni, while 29% (6/21) were identified as C. coli . Phylogeny results suggested the presence of closely related isolates or possible clonal dissemination at the retail level, while phenotypic resistance results showed that 52% (11/21) of Campylobacter isolates were resistant to at least one antibiotic tested, with no isolate being multi-drug resistant. Therefore, intervention strategies against Campylobacter are warranted to reduce its contamination in retail chicken meat. IMPORTANCE Campylobacter species commonly cause foodborne gastrointestinal infections in humans. One challenge is that these bacteria are commensal in chickens, meaning that they thrive in chicken’s intestinal tracts and multiply to up to 10 8 cells per gram of feces without causing clinical signs, resulting in contamination of chicken carcasses or parts during processing and being carried to the retail-level. Their genomic characteristics, including phylogenetic analyses, antimicrobial resistance, and virulence factors, are not well understood. In this study, Campylobacter spp. were often detected in skin-on chicken parts, and >50% of isolates showed phenotypic resistance to at least one clinically important antibiotic tested. The detection of virulent and drug-resistant Campylobacters species in chicken parts at the retail level poses a serious food safety threat. Therefore, it is essential to cook raw chicken meat properly, avoid cross-contamination of chicken meat with other grocery items, and conduct routine food safety-related consumer awareness programs to prevent from Campylobacter -related foodborne infections in humans.