Staphylococcus aureus in Dairy Cattle Milk: Prevalence, Risk Factors, and Antibiogram Profile in Gimbichu Town, Hadiya Zone.

Bovine mastitis, a highly prevalent infectious disease worldwide, frequently involves Staphylococcus aureus as a key etiological agent. This cross-sectional study was conducted from December 2023 to May 2024 in dairy cattle in and around Gimbichu Town, aimed to isolate and identify S. aureus from mastitis lactating cows, identify associated risk factors, and determine antibiogram profiles. Milk samples were collected from 384 cows via simple random sampling. Udder/milk examination and the California mastitis test, respectively, diagnosed clinical and subclinical mastitis. The overall mastitis prevalence was 39.06% (6% clinical and 33.06% subclinical). Multivariable analysis identified parity, lactation stage, udder injuries, age, breed, and housing hygiene as significantly associated with mastitis (p < 0.05). S. aureus was isolated from 42% of mastitis milk, with higher isolation rates in subclinical cases (p < 0.01). Antibiogram analysis revealed high resistance to penicillin G, amoxicillin, and tetracycline, with 22.22% of isolates demonstrating resistance to multiple antibiotics across two antimicrobial classes. These findings highlight the significant impact of S. aureus mastitis on dairy production in the study area and emphasize the need for targeted prevention and control strategies, including routine antimicrobial susceptibility testing to mitigate the emergence of drug resistance.