Low prevalence of methicillin resistant Staphylococcus aureus as determined by an automated identification system in two private hospitals in Nairobi, Kenya: a cross sectional study.

Geoffrey Omuse,Beatrice Kabera,Gunturu Revathi

doi:10.1186/s12879-014-0669-y

Abstract

BackgroundStaphylococcus aureus (S.aureus) is a major cause of both healthcare and community acquired infections. In developing countries, manual phenotypic tests are the mainstay for the identification of staphylococci with the tube and slide coagulase tests being relied upon as confirmatory tests for S. aureus. The subjectivity associated with interpretation of these tests may result in misidentification of coagulase negative staphylococci as S.aureus. Given that antibiotic resistance is more prevalent in CONS, this may result in over estimation of methicillin resistant S.aureus (MRSA) prevalence.MethodsA review of susceptibility data from all non-duplicate S.aureus isolates generated between March 2011 and May 2013 by the Vitek-2 (bioMérieux) automated system was performed by the authors. The data was generated routinely from processed clinical specimens submitted to the microbiology laboratories for culture and sensitivity at the Aga Khan University Hospital and Gertrude’s children’s hospital both situated in Nairobi.ResultsAntimicrobial susceptibility data from a total of 731 non-duplicate S.aureus isolates was reviewed. Majority (79.2%) of the isolates were from pus swabs. Only 24 isolates were both cefoxitin and oxacillin resistant while 3 were resistant to oxacillin but susceptible to cefoxitin giving an overall MRSA prevalence of 3.7% (27/731). None of the isolates were resistant to mupirocin, linezolid, tigecycline, teicoplanin or vancomycin.ConclusionThe prevalence of MRSA in this study is much lower than what has been reported in most African countries. The significant change in antibiotic susceptibility compared to what has previously been reported in our hospital is most likely a consequence of the transition to an automated platform rather than a trend towards lower resistance rates.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0669-y) contains supplementary material, which is available to authorized users.

Highlights

Staphylococcus aureus (S.aureus) is a major cause of both healthcare and community acquired infections
Antimicrobial susceptibility data from a total of 731 nonduplicate S.aureus isolates was reviewed with Aga Khan University Hospital Nairobi (AKUHN) and Gertrude’s Children’s Hospital (GCH) contributing 529 and 202 respectively
Pus swabs formed the bulk of the specimens comprising 79.2% with majority coming from patients with skin and soft tissue infections

Summary

Introduction

Staphylococcus aureus (S.aureus) is a major cause of both healthcare and community acquired infections. Given that antibiotic resistance is more prevalent in CONS, this may result in over estimation of methicillin resistant S.aureus (MRSA) prevalence. Staphylococcus aureus (S. aureus) is a major cause of both healthcare and community acquired infections and is perhaps the single most common cause of healthcareassociated infection throughout the world [1,2,3]. In Africa, methicillin resistant S.aureus (MRSA) prevalence is quite. A study carried out in Kenya in 1997 reported an MRSA prevalence of 39.8% amongst S.aureus isolates from a variety of clinical specimens at the national referral hospital in Nairobi [6]. A study looking at MRSA prevalence in 8 African countries found it to be between 20% and 30% in Nigeria, Cameroon and Kenya. A retrospective analysis of bloodstream isolates at the Aga Khan University Hospital Nairobi (AKUHN) in

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