AUTHOR=Guk Jae-Ho , Song Hyokeun , Yi Saehah , An Jae-Uk , Lee Soomin , Kim Woo-Hyun , Cho Seongbeom 

TITLE=Hyper-Aerotolerant Campylobacter coli From Swine May Pose a Potential Threat to Public Health Based on Its Quinolone Resistance, Virulence Potential, and Genetic Relatedness

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.703993

DOI=10.3389/fmicb.2021.703993

ISSN=1664-302X

ABSTRACT=<p><italic>Campylobacter</italic>, a major foodborne pathogen, is susceptible to oxygen. Recently, aerotolerant <italic>Campylobacter</italic> with enhanced tolerance to aerobic stress has become a major concern in food safety. However, the aerotolerance of <italic>Campylobacter coli</italic> from pigs has not been studied extensively. Here, we sought to investigate the prevalence of <italic>C. coli</italic> across multiple swine groups in farms, including weaning, growing, and fattening pigs in production stages and pregnant sows. Additionally, we analyzed <italic>C. coli</italic> aerotolerance, quinolone resistance, virulence potential, and multilocus sequence typing (MLST) genotypes. Finally, we compared the characteristics of <italic>C. coli</italic> according to the aerotolerance levels. In total, we obtained 124 (66.3%) <italic>C. coli</italic> isolates from 187 swine fecal samples across six swine farms. The pathogen was prevalent in weaning (45.5%), growing (68.3%), and fattening (75.4%) pigs, and pregnant sows (66.7%). Hyper-aerotolerant HAT <italic>C. coli</italic> (13.7% of 124 isolates) was present in all swine groups, with the highest proportion in the pregnant sows (27.3%). All HAT isolates possessed diverse virulence-related genes such as <italic>flaA</italic>, <italic>cadF</italic>, <italic>pldA</italic>, <italic>ceuE</italic>, and <italic>cdtA</italic>. All <italic>C. coli</italic> isolates were resistant to quinolones, and 12 (10%) presented high-level ciprofloxacin resistance (MIC ≥ 32 μg/mL). The proportion of <italic>C. coli</italic> isolates with a high-level ciprofloxacin resistance was the highest in HAT <italic>C. coli</italic> (18.8%). Furthermore, six MLST sequence types (STs) (ST827, ST830, ST854, ST1016, ST1068, and ST1096) of swine-derived <italic>C. coli</italic> were in common with human-derived <italic>C. coli</italic> (PubMLST). The proportion of <italic>C. coli</italic> belonging to such shared STs at each aerotolerance level was the highest in HAT <italic>C. coli</italic> (HAT vs. oxygen-sensitive; OR = 3.13). In conclusion, quinolone resistance of <italic>C. coli</italic> may be distributed throughout in all swine groups in farms. HAT <italic>C. coli</italic> is likely to remain in pig farms and re-infect other pigs in the farms. Furthermore, swine-derived HAT <italic>C. coli</italic> could be transmitted to humans easily through the food chain owing to its aerotolerance, and it could pose a threat to public health owing to its high-level ciprofloxacin resistance and virulence. This study highlights the need to develop management practices that prevent the transmission of swine-derived HAT <italic>C. coli</italic> to humans.</p>