Prevalence and antimicrobial susceptibility pattern of Staphylococcus Aureus isolated from clinical specimens at the Mater Hospital Nairobi, Kenya.

Abstract Staphylococcus aureus is a leading cause of hospital and community acquired infections globally. Surveillance of prevalence and antibiotic susceptibility patterns is important to ensure appropriate antibiotic prescription. The aim of this study was to determine the prevalence and susceptibility patterns of Staphylococcus aureus isolated from clinical specimens in a tertiary referral and training hospital.A retrospective study was conducted at the Mater Misericordiae Hospital, Nairobi.It involved analyzing records of specimens analyzed between January 2014 and December 2018. Strains phenotypically resistant to <3 non β-lactam antimicrobial categories were defined as non-multidrug-resistant MRSA (nmMRSA) and strains that were resistant to ≥3 non-β-lactam antimicrobial groups were defined as multidrug-resistant MRSA (mMRSA). A specimen was categorized as Penicillin susceptible (PSSA) if susceptible to Penicillin and Oxacillin, MSSA if resistant to Penicillin and susceptible to Oxacillin, and MRSA if resistant to Oxacillin and Penicillin.ResultsPSSA accounted for 60.85%, (401/659)of S.aureus cultured.The prevalence of MSSA was 38.54%(254/659).MRSA was the least prevalent.(0.61%,4/659).No multi-drug Methicillin resistant S. aureus were isolated in the five-year period.PSSA accounted for 60.85%(401/659)of all S.aureus isolates.100% of MRSA isolated was sensitive to Vancomycin, Linezolid, Tigecycline, Tetracycline and Rifampicin. MRSA was resistant to Clindamycin and Erythromycin.Conclusion;The prevalence of MRSA was low compared to previous studies.All strains isolated were non-multidrug resistant.There was no resistance to Vancomycin detected.Penicillins are still a viable option in the treatment of majority of S.aureus infections in our setting.