Species Distribution, Antimicrobial Resistance, and Enterotoxin Profiles of Non-aureus Staphylococci Isolated from Poultry Slaughterhouses in Korea

Although non-aureus staphylococci (NAS), such as coagulase-negative staphylococci (CoNS), can substantially affect human and animal health, information on NAS species distribution in poultry slaughterhouses and their antimicrobial resistance (AMR) profiles is limited. In this study, we analyzed the prevalence of NAS species and AMR profiles of NAS isolates collected from poultry slaughterhouses, including chicken carcasses and facility environments. In total, 100 NAS isolates were collected from six poultry slaughterhouses in Korea. The AMR patterns of the NAS species and the major genetic elements associated with AMR phenotypes, particularly methicillin and fluoroquinolone resistance, were determined. In addition, the prevalence of classical staphylococcal enterotoxin (SE, sea-see) and toxic shock syndrome toxin-1 (tst-1) genes among NAS isolates was examined. Among the 10 NAS species, coagulase-negative Staphylococcus simulans (n=49, 49%) was the most dominant species, followed by Staphylococcus agnetis (n=16, 16%). The multiple drug resistance phenotype was identified in 67% (n=67) of the NAS isolates, with the highest resistance to erythromycin (66%) and clindamycin (62%). Furthermore, fluoroquinolone resistance was confirmed in 34 (34%) NAS isolates. Fifteen NAS isolates were mecA-positive, harboring staphylococcal cassette chromosome mec (SCCmec) I (n=2), SCCmec IV (n=1), or non-typeable SCCmec types (n=12). Carriage of SE genes was detected in none of the NAS isolates, and tst-1 was detected in only two CoNS strains. Our results suggest that NAS in poultry slaughterhouses can have potential role in the maintenance and transmission of AMR.