Species Profiles and Antimicrobial Resistance of Non- Staphylococci Isolated from Healthy Broilers, Farm Environments, and Farm Workers.

Non- staphylococci (NAS), particularly antimicrobial-resistant NAS, have a substantial impact on human and animal health. In the current study, we investigated (1) the species profiles of NAS isolates collected from healthy broilers, farm environments, and farm workers in Korea, (2) the occurrence of antimicrobial-resistant NAS isolates, especially methicillin resistance, and (3) the genetic factors involved in the methicillin and fluoroquinolone resistance. In total, 216 NAS isolates of 16 different species were collected from healthy broilers (n=178), broiler farm environments (n=18), and farm workers (n=20) of 20 different broiler farms. The two most dominant broiler-associated NAS species were (23.6%) and (22.9%). Six NAS isolates were -positive carrying staphylococcal cassette chromosome (SCC) II (n=1), SCC IV (n=1), SCC V (n=2), or non-typeable SCC element (n=2). While two -positive isolates from farm workers had SCC II and IV, a -positive isolate from broiler and a isolate farm environment carried SCC V. The occurrence of multidrug resistance was observed in 48.1% (104/216 isolates) of NAS isolates with high resistance rates to β-lactams (>40%) and fusidic acid (59.7%). Fluoroquinolone resistance was confirmed in 59 NAS isolates (27.3%), and diverse mutations in the quinolone resistance determining regions of , , , and were identified. These findings suggest that NAS in broiler farms may have a potential role in the acquisition, amplification, and transmission of antimicrobial resistance.