Molecular typing, phenotypic and genotypic assessment of antibiotic resistance and virulence factors amongst the Staphylococcus aureus bacteria isolated from raw chicken meat

Abstract

Background: Staphylococcus aureus is an important cause of foodborne diseases due to the consumption of contaminated raw chicken meat. The present research was performed to evaluate the phenotypic and genotypic properties of antibiotic resistance, virulence factor profiles and molecular typing of S. aureus strains isolated from chicken meat. A total of 36 S. aureus strains were isolated from raw chicken meat samples. Phenotypic pattern of antibiotic resistance was assessed by disk diffusion. Distribution of antibiotic resistance and virulence genes was evaluated by PCR. Molecular typing of isolates was perform ed by the ERIC-PCR. Results:Considering the over than 80% similarity, 36 S. aureus isolates were classified in 9 different profiles with 43 to 100% similarities. S. aureus strains showed the highest incidence of resistance against penicillin (100%), tetracycline (91.66%), cephalothin (77.77%), ciprofloxacin (75%), erythromycin (75%), mupirocin (63.88%), clindamycin (61.11%) and trimethoprim/sulfamethoxazole (61.11%). The most commonly detected antibiotic resistance genes amid the S. aureus isolates were mecA (100%), tetK (80.55%), tetM (66.66%), aacA-D (61.11%), msrA (55.55%) and ermA (55.55%).Total distribution of etB, etA, tsst-1, clfA and coa virulence factors amongst the S. aureus strains was 61.11%, 58.33%, 13.88%, 75% and 100%, respectively. Conclusions:Genetic cluster of bacteria affected the antibiotic resistance and virulence characters of S. aureus strains. S. aureus strains with the same ERIC-genetic cluster had similar antibiotic resistance and virulence characters which may show their similar origins. Presence of one or more virulence factors and antibiotic resistance genes amongst the resistant-S. aureus strains signifies an important public health threat rendering the consumption of raw or undercooked chicken meat.