Comparison of subsequent infection in methicillin-resistant Staphylococcus aureus nasal carriers between ST72 community-genotype and hospital genotypes: a retrospective cohort study

BACKGROUND: Carriage of methicillin-resistant Staphylococcus aureus (MRSA) is an important risk factor of subsequent infection. The purpose of our study was to compare the rates of subsequent infection among newly-admitted patients carrying MRSA between community-genotype and hospital-genotypes METHODS: In this retrospective cohort study, we compared the rates of subsequent MRSA infection, time to subsequent infection and mortality in the following 6 months between the community-genotype ST72 MRSA cohort and the hospital-genotypes ST5 / ST239 MRSA cohort. RESULTS: We identified 198 patients carrying ST72 and 156 patients carrying ST5 or ST239. There was no difference in the rates of subsequent infection between ST72 cohort and ST5 / ST239 cohort (13.1% vs. 12.8%; P = 0.931). The median time to development of subsequent infection was not significantly different (27 days vs. 88 days; P = 0.0877). The Kaplan-Meier method showed no difference in the cumulative rate of being free of subsequent infection between the cohorts (P = 0.9209). Overall mortality rates at 6 months did not differ (1.5% vs. 1.9%; P = 1.000) CONCLUSIONS: We found no evidence that rates of subsequent MRSA infection were different between newly-admitted patients carrying community-genotype ST72 MRSA and those whom carrying hospital-genotypes ST5 or ST239 MRSA.