Characteristics of Archived Coagulase Negative Staphylococci Isolates at a University Hospital, Nairobi, Kenya

Abstract

Background: Coagulase negative Staphylococci (CoNS) are normal inhabitants of the skin and mucous membranes and thus have been dismissed for a long time as culture contaminants even if they have been isolated from sterile specimens. The risk factors for CoNS infections include patients who are immunocompromised, implanted with foreign bodies or with indwelling devices. The aim of this study was to determine the antimicrobial susceptibility patterns and presence of mecA gene in methicillin resistant CoNS isolated in a teaching and referral hospital in Kenya. Methodology: This was a cross sectional retrospective study. Archived isolates were sub-cultured on 5% sheep blood agar. Speciation and antimicrobial susceptibility patterns were performed by Vitek2 technique. The presence of mecA gene was determined by (PCR). Results: A total of seven species were identified with Staphylococcus epidermidis having the highest percentage at 45.4% and Staphylococcus warneri with the lowest at 2.6%. High resistance to antibiotics that were tested was observed regardless of the source of the isolate. MecA gene was found in 90% of the isolates. Conclusion: Coagulase negative Staphylococci exhibited high levels of resistance generally. Most of the isolates carried the mecA gene. Despite some of the isolates being resistant to Cefoxitin, the mecA gene was not found. There is a possibility that methicillin resistance in these isolates is mediated using a different mechanism.