spp. isolated from poultry in Iran: Antibiotic resistance profiles, virulence genes, and molecular mechanisms.

spp. genera is one of the most common causes of microbial enteritis worldwide. The objective of this work was to investigate the antimicrobial resistance (AMR) patterns, virulence genes, and genetic variation of thermophilic species collected from chicken meat samples in Iran. A total of 255 meat specimens were taken and transferred to the laboratory. Culture methods were utilized to identify the genus, and PCR and sequencing were performed to confirm the organisms. Antimicrobial susceptibility evaluation was performed using broth microdilution for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)]. By using PCR, AMR and virulence genes were detected. The detection rate of spp. was 64 (25.09%) out of 255 meat samples, with and accounting for 41 (64.06%) and 14 (21.87%), respectively. Other isolates accounted for 14.06% of the total (nine samples). The antibiotic susceptibility of all isolates was tested using six antibiotics, and all (100%) were resistant to CIP and NAL. However, TET resistance was observed in 93.9% and 83.3% of and isolates, respectively. Four (8.2%) isolates were multidrug-resistant (MDR), while none of the isolates were MDR. Two of the four MDR isolates were resistant to CIP, NAL, TET, and ERY, whereas the other two isolates were resistant to CIP, NAL, TET, and GEN. The values of the Minimum Inhibitory Concentration (MIC) were as follows: CIP, 64-256 μg/ml; NAL, 128-512 μg/ml; TET, 2-1024 μg/ml; SIT, 0.25-1 μg/ml; ERY, 1-32 μg/ml; and GEN, 1-256 μg/ml. , , , , , , , , and were discovered in more than 50% of isolates, although , , , and were found in <50%. , , , and were discovered in more than 50% of the samples, whereas , , , , and were found in less than half. For , the percentages for , , , and were all zero. The results of this study show isolates obtained from poultry have higher resistance to quinolones and TET, pathogenicity potential, and varied genotypes.