Prevalence, antimicrobial resistance, and virulence-associated genes of Campylobacter isolates from raw chicken meat in Shiraz, Iran

Campylobacter is recognized as a major cause of foodborne gastroenteritis in humans in many countries and may be transferred from animals to humans. The consumption of chicken meat is identified as a major cause of Campylobacter infection in humans.

To find out the contamination rate of chicken meat with Campylobacter, the antimicrobial resistance (AMR) pattern, and the virulence-associated genes of theisolates.

Ninety packed chicken meat from 7 main poultry slaughterhouses in Shiraz were analyzed for Campylobacter spp. isolation through microbiological methods. Specific primers were used for the identification of the Campylobacter isolates on species level by polymerase chain reaction (PCR). Antibiotic resistant profiles were determined using the disc diffusion method based on Clinical and Laboratory Standards Institute (CLSI) standards. All the isolates were screened for 7 virulence-associated genes, namely cdtA, cdtB, cdtC, cadF, pldA, cgtB, and virB11 by PCR.

Out of 90 chicken meats, 26 (28.9%) Campylobacter spp. have been isolated. Resistance to ciprofloxacin (CIP), nalidixic acid (NA), and cefixime (CFM) was observed in all the isolates. Resistance to trimethoprim/sulfamethoxazole (SXT), tetracycline (TET), ampicillin (AMP), and chloramphenicol (CHO) was 80.8%, 88.5%, 76.9%, and 30.8%, respectively. Multidrug resistance (MDR) phenotype was observed in 80.8% of the Campylobacter isolates. All the isolates were positive for cdtA, cdtB, cdtC, and cadF genes. pldA and cgtB were detected in 65.4% and 15.4% of the isolates, respectively.

In this study, the presence of several virulence genes and an alarming level of MDR in Campylobacter spp. isolates were reported. Particularly, resistance to CIP and TET should be highlighted, since both are key drugs for the treatment of human campylobacteriosis.