Staphylococcus aureus in cow milk and milk products in Ambo and Bako towns, Oromia, Ethiopia: prevalence, associated risk factors, hygienic quality, and antibiogram

Background: Staphylococcus aureus is one of the foodborne gram-positive bacterial pathogens that cause staphylococcal food poisoning worldwide and can contaminate foods of animal origin. The current study was conducted in Ambo and Bako towns, Ethiopia to estimate the prevalence, associated risk factors, hygienic quality, and antibiogram of Staphylococcus aureus (S. aureus) in cow’s raw milk and milk products.Results: The overall prevalence of S. aureus from milk and milk products was 15.6% (94/601) with the highest prevalence detected in bulk tank raw milk at 17.50% (14/80) and the lowest in ‘Ergo’ at 13.11% (8/61). Age of cows, previous history of treatment, stage of lactation, udder washing, use of towel for individual cow, tick infestation, hygiene of the milker and utensils, and use of disinfectant were found to be statistically significant (PS. aureus isolation at the individual cow level. Accordingly, a higher probability of getting infected with S. aureus was detected in cows aged 5 years old, crossbreeds, had a history of previous treatment, mid-lactation stage, no udder washing practiced, no individual towel used, tick infestation, and poor milking hygiene. Personnel hygiene, container hygiene, and use of disinfectants were the major risk factors that had a statistically significant association (pS. aureus. The maximum S. aureus counts at the farm and restaurant levels were 1.92x104 CFU/mL and 1.86x104 CFU/mL, respectively. The antimicrobial susceptibility test showed a higher resistance of S. aureus against amoxicillin (98.48%), oxacillin (98.48%), ampicillin (98.48%), cefoxitin (92.42%), and tetracycline (83.33%), of which 43.94% of isolates showed multidrug resistance. The high prevalence of oxacillin and cefoxitin-resistant isolates, which is indicative of the existence of Methicillin-Resistant Staphylococcus aureus (MRSA), was also detected in the current study.Conclusion: Higher prevalence of S. aureus and the multidrug-resistant isolates in milk and milk products is detected in study areas. Therefore, to make milk and milk products safe for human consumption, hygienic handling of milk and milk products, regular surveillance of antimicrobial resistance, and prudent use of drugs are suggested.