Dissemination of methicillin-resistantStaphylococcus aureusSCCmectype IV and SCCmectype V epidemic clones in a tertiary hospital: challenge to infection control

Abstract

SUMMARYTwo-hundred MRSA strains from inpatients with healthcare-associated (HA) and 100 MRSA strains from outpatients with community-associated (CA) skin and soft tissue infections (SSTIs) were tested for antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec) typing, Panton–Valentine leucocidin (PVL) toxin,sehandarcAgenes. Based on SCCmectyping, HA-MRSA isolates were further divided into HA-SCCmecI/II/III MRSA and HA-SCCmecIV/V MRSA, and CA-MRSA isolates into CA-SCCmecI/II/III MRSA and CA-SCCmecIV/V MRSA. SCCmectypes were further characterized by pulsed-field gel electrophoresis,spatyping and multi-locus sequence typing. Seventy-five (37·5%) HA-MRSA isolates and 83/100 CA-MRSA isolates were SCCmecIV/V genotype. HA-SCCmecIV/V MRSA was associated with malignancy (P = 0·03) and bone fractures (P = 0·02) compared to CA-SCCmecIV/V MRSA. HA-SCCmecIV/V MRSA was associated with PVL gene carriage compared to HA-SCCmecI/II/III MRSA (P < 0·001). ST22-MRSA-IV (EMRSA-15), ST772-MRSA-V, and ST36-MRSA-IV and ST239:EMRSA-I:III were the major clones identified. Our study documents the emergence of SCCmecIV and SCCmecV MRSA clones in an Indian hospital.