<![CDATA[Antibiotic resistance in livestock is an increasingly significant issue that affects animal health, food safety, and public health. Staphylococcus aureus is an important pathogenic bacterium in layer chickens and has the potential to serve as a source of resistant bacterial spread. This study aimed to determine the antibiotic resistance profile of S. aureus isolated from cloacal swabs of layer chickens in Bangli Regency, Bali. A total of 20 cloacal swab samples from clinically healthy layer chickens were cultured on Mannitol Salt Agar and identified through Gram staining, the catalase test, and mannitol fermentation characteristics. Antibiotic susceptibility testing was performed using the Kirby–Bauer disk diffusion method and interpreted according to Clinical and Laboratory Standards Institute. The results showed that 12 isolates (60%) were identified as S. aureus, with a higher prevalence in layer chickens (80%) compared with pre-layer chickens (40%). The highest resistance was observed against erythromycin (91.67%), followed by ciprofloxacin and sulfamethoxazole–trimethoprim (each 41.67%), while all isolates were sensitive to chloramphenicol. These findings indicate that S. aureus from layer chickens in Bangli Regency exhibits a high level of resistance to erythromycin, whereas chloramphenicol remains effective. The results highlight the need for prudent antibiotic use, strengthened biosecurity, and routine resistance monitoring to prevent the spread of resistant bacteria in layer farms.]]>
