Drug resistant and multilocus sequence typing of Campylobacter coli from pig source in Jiangsu province

Abstract:

[Background] Campylobacter is one of the most common zoonotic pathogens and is a leading cause of human gastroenteritis through food chain. [Objective] To study the phenotypic resistance and molecular type of Campylobacter isolated from pig source in ten intensive pig farms of Jiangsu province. [Methods] The minimal inhibitory concentrations (MICs) was determined by agar dilution method and the resistance genes were detected by polymerase chain reaction (PCR). Seven Campylobacter housekeeping genes including aspA, glnA, gltA, glyA, pgm, tkt and uncA were amplified and sequenced, then the sequences of genes were analysed through multilocus sequence typing (MLST). [Results] A total of 22 isolates were identified from 100 samples (22%), the detection of Campylobacter was independent of breeding scale and age (P>0.05). 81.82% of the isolates were resistant to three or more than three drugs, resistance rates to ten drugs were under different degrees, gentamicin (36.36%), streptomycin (50%), clindamycin (27.27%), chloramphenicol (13.64%), tetracycline (40.91%), ciprofloxacin (18.18%), nalidixic acid (63.63%), telithromycin (59.09%), erythromycin (100%), azithromycin (81.82%). The resistance-genes detection rates to cfr, adE-Sat4-aphA, ermB and Tet(O) were 4.5%, 59.1%, 9.1% and 100%, MLST results showed that 11 sequence types were found and CC-828 was the prevalent clonal complex (100%), Evolutionary tree results showed that all strains were belonged to two groups, which had two branches and nine branches, respectively. χ2 test and Logistic regression analysis showed that three sequence types (STs) were associated with their corresponding antimicrobial agents. [Conclusion] The high resistance to macrolides antibiotics and the high detection of Tet(O) were found in Campylobacter coli from swine feces, C. coli population showed diverse genetic nature.