Molecular types and related clinical features of methicillin-resistant Staphylococcus aureus in ;Jingzhou area / 中华临床感染病杂志

ABSTRACT

Objective To investigate the molecular types and related clinical features of methicillin-resistant Staphylococcus aureus (MRSA) in Jingzhou area, Hubei Province.Methods A total of 80 MRSA strains confirmed by mecA gene were isolated from inpatients in Jingzhou Central Hospital of Hubei province during January and December 2014. Vitek 2 Compact was used for antibiotic susceptibility test . Staphylococcus protein A (SPA) types and Staphylococcal cassette chromosome mec (SCCmec) genotypes were detected by multiplex polymerase chain reaction ( PCR ) and gene sequencing . Panton-valentine leucocidin ( pvl) gene of the strains was detected by PCR .Chi-square test and Wilcoxon test were used for data analysis .Results There were 16 spa types in 80 MRSA isolates , in which t030 and t437 were the most prevalent ones accounting for 50.0% ( 40 strains ) and 28.8% ( 23 strains ) of the total strains, respectively.There were 77 strains of SCCmec type Ⅰ-Ⅴ, in which SCCmecⅢ and SCCmecⅣ were the most prevalent ones accounting for 45.0% (36 strains) and 35.0% (28 strains), respectively.t030 was the main spa type in isolates of SCCmecⅢ(33/36, 91.7%), while t437 was the main spa type in isolates of SCCmecⅣ(20/28, 71.4%).Patients infected with t030/SCCmecⅢMRSAs were with higher ages than those infected with t437/SCCmecⅣMRSAs (T=446.500 and 607.500, P<0.01).Patients infected with t030/SCCmecⅢ MRSAs were mainly from surgical wards and intensive care unit ( ICU ) , while those infected with t437/SCCmecⅣ MRSAs were mainly from pediatrics wards , and there were significant differences in ward distribution between two groups (χ2 =33.724 and 29.768, P <0.01).Seventy percent and above strains of t030/SCCmec type Ⅲ were resistant to rifampin, erythromycin, clindamycin, tetracycline, levofloxacin, moxifloxacin, ciprofloxacin and gentamicin .Strains of t437/SCCmec type Ⅳwere resistant to erythromycin , clindamycin and tetracycline , but were sensitive to most non-β-lactam antimicrobial drugs (with resistance rates <20%).Virulence gene pvl was found in 11 strains (13.8%), in which 7 were strains of t437-SCCmec typeⅣ.Conclusions MRSAs in Jinzhou are of various genotypes , in which t030-SCCmecⅢand t437-SCCmecⅣare the most prevalent ones .Strains of t030-SCCmec typeⅢare usually multiple-drug resistant , mainly seen in elderly patients in surgical wards and ICU .Strains of t437-SCCmecⅣare sensitive to most non-β-lactam antimicrobial drugs , and its infection is mainly seen in children and young people .