Abstract:
Staphylococcus aureus specifically methicillin-resistant S. aureus (MRSA) is a known healthcare-associated infection pathogen. The objectives of this study is to characterize the phenotype, genotype and epidemiology of S. aureus isolates from two tertiary hospitals, Institut Jantung Negara (IJN) and University Malaya Medical Centre (UMMC) in Kuala Lumpur. The incidence rate of MRSA was 1.42 (95% CI: 0.68 – 1.21) in IJN was higher than that of UMMC, 0.89 (95% CI: 0.68 – 1.20) per 1000 inpatient admission respectively. The prevalence of MRSA in UMMC (52.5%) was
higher than IJN (42.4%, p=0.217). MRSA was not significantly associated with age, gender and ethnic distribution in both hospitals. In IJN, majority (57.6%) of the isolates were classified as healthcare-associated infection (HAI) whereas community-acquired infection (CAI) was dominant in UMMC (61.4%) p=0.020. The dominant SCCmec type in both hospitals was type IV with 96.0% and 92.5% and type V at 4.0% and 7.5% in IJN and UMMC respectively (p=1.000). Subtype IVa was dominant in UMMC (55.1%) whereas large proportion of IJN isolates (64%) were un-typable. The presence of pvl gene was significantly higher in UMMC compared to IJN (33.7% vs 5.1%, p=0.000). PFGE cluster analysis showed the isolates were genetically diverse and evidence of crossover of MRSA infection between hospital and community setting and clonal relatedness between MRSA and MSSA among these isolates. MRSA isolates showed good sensitivity towards tigecycline and vancomycin in both hospitals but
were resistant to erythromycin which is recommended for MRSA. In IJN, patient with no hypertension was significantly associated with higher mortality from MRSA infection (p=0.017), whereas in UMMC, mortality was significantly associated with HA-MRSA (p=0.028), no soft tissue infection (p=0.001) and bacteraemia/bloodnstream infection (p=0.000).
Keywords:
MRSA, genotypic, phenotypic, SCCmec, pvl gene, PFGE, HAI, CAI
