Isolation, identification, and determination of antibiogram characteristics of Staphylococcus aureus in cow milk and milk products (yoghurt and cheese) in West Showa Zone, Ethiopia

Abstract

Cross-sectional research aimed to identify Staphylococcus aureus from milk, yoghurt, and cheese collected from selected towns in the west Showa zone was conducted from May 2020 to March 2021. The isolates were identified based on colony characterisation, Gram stain, and coagulase tests, and matrix assisted laser desorption/ionisation time-of-flight biotyper. The drug susceptibility test was conducted using the disk diffusion method. The presence of mecA, blaZ, and nuc genes was assessed by polymerase chain reaction. The data were analysed using SPSS Ver.20. The result revealed that S. aureus was identified in 20.3%, 14.9%, and 4.8% of milk, cheese, and yoghurt samples, respectively. The rate was significantly higher in milk (OR = 5.04), and in cheese (OR = 1.46) than in yoghurt (p < 0.05). All 24 tested isolates were resistant to penicillin, tetracycle, and oxytetracycline. The nuc gene was found in all 24 tested isolates but no mecA and blaZ genes were tested.