Epidemiological investigation of community-acquired methicillin resistant Staphylococcus aureus infection from 4 hospitals in Beijing / 中华检验医学杂志

ABSTRACT

ObjectiveTo investigate the prevalence,antibiotic characteristics as well as molecular background of community-associated methicillin-sensitive Staphylococcus aureus (CA-MRSA) from patients with skin and sofi tissue infections from 4 different hospitals in Beijing.MethodsFive hundred and one patients were enrolled from 4 hospitals prospectively.Patients with skin and soft tissue infections and no risk factors for healthcare-associated acquisition were included.Sample from the infection sites were collected for culture.Case report form was filled out for each patient.Antibiotic susceptibility test and molecular analysis was performed for each Staphylococcus aureus isolate.ResultsTotally 164 Staphylococcus aureus isolates were cultured from the patients with skin and soft tissue infections.Of them 5 isolates were CA-MRSA.These 5 CA-MRSA isolates harbored SCCmec Ⅰ, SCCmec Ⅲ, SCCmec Ⅳ,SCCmec Ⅴ and untypable,respectively.CA-MRSA was highly resistant to β-lactamase,levofloxacin,erythromycin and clindamycin,but susceptible to vancomycin,teicoplanin,linezolid,daptomycin,and trimethoprim/sulfamethoxazole.Prevalence of PVL in community-associated methicillin sensitive Staphylococcus aureus(CA-MSSA) and CA-MRSA were 41.9％ and 2/5.Other toxins expressed similarly between them.Combined with multilocus sequence typing (MLST) and spa typing,the major clones of CA-MSSA were ST398-t034,ST7-t796,ST398-t571,ST1t127,and ST188-t189,while in CA-MRSA were ST239-t037-SCCmec Ⅰ,ST239-t632-SCCmecⅢ,ST59-t437-SCCmecV,ST8-t008-SCCmecⅣ,and ST6-t701-NT.ConclusionsThe low prevalence of CA-MRSA in Beijing and complexity of the genetic background in CA-MRSA were observed.Clone spread is not found among CA-MRSAisolates.CA-MRSAexhibithigher resistancecomparedwithmethicillinsensitive Staphylococcus aureus (MSSA).Rational drug use scheme is called in the clinical practice to prevent development of high level resistance.