SCCmec genotyping and antimicrobial susceptibility of communityacquired methicillinresistant Staphylococcus aureus

Abstract:

ObjectiveTo investigate the types of staphylococcal cassette chromosome mec (SCCmec) gene and antimicrobial resistance of communityacquired methicillinresistant Staphylococcus aureus(CAMRSA) isolated from outpatients and inpatients in a hospital.MethodsMRSA strains isolated between May 2011 and August 2015 in a hospital and the relevant case data were collected, polymerase chain reaction(PCR) method was used to identify mecA gene of MRSA and SCCmec gene of CAMRSA, antimicrobial susceptibility testing of CAMRSA were performed and analyzed.ResultsA total of 305 MRSA isolates were collected, 296 of which were mecA positive, 29.73%（88/296） were CAMRSA. The genotyping of CAMRSA showed that 48 strains were SCCmec type Ⅳ, 36 were SCCmec type V, the other 4 strains were undefined. Antimicrobial susceptibility testing results showed that susceptibility rates of CAMRSA to vancomycin, linezolid, and tigecycline were all 100%, resistance rates to penicillin and oxacillin were both 100%; resistance rates of SCCmec type IV and SCCmec type V CAMRSA strains to levofloxacin, rifampicin, and ciprofloxacin were all significantly different (all P<0.05), to ampicillin/sulbactam, furantoin, and erythromycin were all >58%.ConclusionThe main SCCmec type of CAMRSA are type IV and type V in this hospital, antimicrobial resistance rate is high, clinicians should pay high attention, and use antimicrobial agents according to antimicrobial susceptibility testing results.