Prevalence and antimicrobial susceptibility profile of Staphylococcus aureus isolated from marketed milk and cheese in Ilorin, Nigeria

Abstract

The irrational use of drugs, especially antimicrobials as growth promoters, and in the management of disease conditions without proper diagnosis has led to a higher incidence of multidrug resistance/antimicrobial resistance, which is a leading cause of death both in humans and animals. Improper diagnosis, irrational use of drugs and lack of adherence to withdrawal periods are factors incriminated in the incidence of multidrug resistance pathogens. This study was aimed at examining the prevalence, isolation, and antimicrobial susceptibility profile of Staphylococcus (S.) aureus in marketed milk and cheese in Ilorin, Kwara State, Nigeria. Using a cross-sectional study design which involved sampling of milk and cheese (n = 340) from four markets (Gambari, Ojaoba, Sango and Ipata) in Ilorin metropolis, Staphylococcus aureus (S. aureus) was isolated using standard microbiological procedures. Antimicrobial susceptibility testing of all positive isolates was done using the disk diffusion method. The prevalence of S. aureus was 3.5% in nono milk and 0.0% in cheese. The S. aureus isolated showed 100% resistance to ampicillin, ceftazidime and oxacillin and a high resistance rate to cefoxitin (91.7%), ceftriaxone (83.3%) and tetracycline (83.3%). Ciprofloxacin, gentamicin, and azithromycin showed lower resistance (25%) to the tested S. aureus isolates. The S. aureus isolates displayed six different resistance patterns and were resistant to three or more antibiotics. Particularly, three isolates were pan-resistant. This study emphasizes the importance of good management and hygiene practices throughout the milk processing value chain to ensure the quality and safety of the final product for consumers.