Coexistence of mupirocin and antiseptic resistance in methicillin-resistant Staphylococcus aureus isolates from Korea

In this study, we determined the prevalence of mupirocin and antiseptics resistance in methicillin-resistant Staphylococcus aureus (MRSA) at a secondary- and a tertiary-care hospital in Korea. Mupirocin susceptibility test, ileS gene sequencing, and polymerase chain reaction for mupA, qacA/B, and smr gene were performed with 456 nonduplicated MRSA isolates collected from 2 hospitals in Korea. Genetic relatedness was determined by spa typing and multilocus sequence typing (MLST). The rates of low-level and high-level mupirocin resistance were 7% and 2% in the secondary-care hospital and 17% and 2% in the tertiary-care hospital, respectively. The positive rate of qacA/B and smr gene in mupirocin-resistant MRSA was 65% and 71%, respectively. In spa typing, most mupirocin-resistant MRSA showed genetic relatedness and some of the highly resistant isolates were ST239 and ST5 in MLST analysis. The distribution of low-level and high-level mupirocin resistance and the coexistence of antiseptic resistance in MRSA can result in failure of decolonization in Korea.