Antimicrobial resistance features and molecular typing of clinically isola-ted m ethicillin-resistant Staphylococcus aureus / 中国感染控制杂志

ABSTRACT

Objective To study antimicrobial resistance and genotyping of methicillin-resistant Staphylococcus au-reus(MRSA). Methods A total of 967 no-repetitive strains of Staphylococcus aureus(S.aureus)isolated from a hospital between January 2014 and November 2015 were collected,antimicrobial susceptibility testing,mecA gene,and Panton-Valentine leukocidin gene(PVL gene)were detected;staphylococcal cassette chromosome mec(SCCmec)typing,multilocus sequence typing(MLST),S.aureus protein A(spa)gene typing,and S.aureus ac-cessory gene regulator(agr)typing were performed with multiplex polymerase chain reaction. Results Of 967 strains of S.aureus,210(21.72%)were MRSA;detection rate of MRSA from sputum specimen was higher than that of skin and soft tissue specimen(68.09% vs 1 1.83% ,P<0.05);vancomycin- and linezolid-resistant S.aureus strains were not found,susceptibility rates of MRSA to gentamicin,tetracycline,erythromycin,clindamycin,levo-floxacin,ciprofloxacin,moxifloxacin,nitrofurantoin,and rifampicin were all lower than those of methicillin-sensi-tive Staphylococcus aureus(MSSA),differences were all statistically significant(all P<0.05);antimicrobial sus-ceptibility rate of MRSA to compound sulfamethoxazole was higher than MSSA,difference was significant(P<0.05). Susceptibility rates of MRSA isolated from skin and soft tissue to gentamicin,levofloxacin,ciprofloxacin,moxifloxacin,and rifampicin were 86.90% -95.24%,while MRSA isolated from sputum were only 1.56% -15.63%.Of 967 strains of S.aureus,210 harbored mecA gene,10 harbored PVL gene,8(3.81%)of 210 MRSA strains weren't typed. The main types of MLST,SCCmec,spa,and agr were ST 239(n= 177 strains),type Ⅲ(n= 177 strains),t 030(n= 177 strains),and typeⅠ(n= 196 strains)respectively.Conclusion The main epidemic clone of MRSA strain in this hospital is ST239-MRSA-SCCmec III-t030,antimicrobial resistance is serious,monitoring on drug-resistant strains in hospital should be strengthened.