Carriage, antimicrobial susceptibility profiles and genetic diversity of <i>Staphylococcus aureus</i> and MRSA isolates recovered from students in a Kenyan university

Abstract

Objective: To determine the carriage, antimicrobial susceptibility profiles and genetic diversity of Staphylococcus aureus and MRSA isolates recovered from students in a Kenyan University. Study design: A cross sectional descriptive study. Setting: Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya. Subjects: A total of 237 healthy students residing within the University residence halls were recruited. Results: A total of 231 S. aureus isolates were recovered. All isolates were susceptible to nitrofurantoin and linezolid and resistant in high numbers (194, 81.9%) to ampicillin. Resistances to amoxicillin-clavulanic acid, erythromycin, chloramphenicol, gentamicin, ciprofloxacin, norfloxacin and trimethoprimsulfamethoxazole were below 20%. The overall prevalence of MRSA among the study population was 11.3% (26/231). Based on carriage of the mec cassettes, the SCCmecV (61.5%) was more prevalent among the MRSA followed by SCCmecII (53.9%). Carriage of the lukFS-PV gene was 26.9% and 35.7% among the MRSA and MSSA strains respectively, and there was no statistical association between the two strains with regard to carriage of the gene (p=0.487). Analysis of genetic relations showed evidence of strain sharing among students. Conclusion: The study revealed the presence of MRSA strains, which are also multi-drug resistant, circulating among a healthy student population in a university setting within Central Kenya. Therefore, these results indicate the existence of potential risk factors, thus necessitating a comprehensive surveillance on MRSA and studies on control measures to help in curbing the spread of MRSA strains.