荆州地区耐甲氧西林金黄色葡萄球菌的分子型别及相关临床特征

Molecular types and related clinical features of methicillin-resistant Staphylococcus aureus in ;Jingzhou area

目的：了解湖北省荆州地区流行的耐甲氧西林金黄色葡萄球菌（ MRSA）的主要分子型别和相关临床特征。方法连续收集2014年1至12月分离自湖北省荆州市中心医院住院患者并经mecA基因检测确证为MRSA的80株临床分离株。采用全自动微生物检测仪Vitek 2 Compact对所有菌株进行药敏试验，采用多重聚合酶链反应（ PCR）和基因测序分别检测菌株的葡萄球菌A蛋白（ SPA）和葡萄球菌染色体mec基因盒（ SCCmec）分子型别，并采用PCR法检测所有菌株的杀白细胞素（ PVL）基因。采用χ2和Wilcoxon秩和检验对数据进行处理。结果80株MRSA中共检出16种spa基因型别，以t030和t437为主，分别为40株（50％）和23株（28．8％）；共检测到SCCmecⅠ～Ⅴ型77株，以SCCmecⅢ和SCCmecⅣ型检出最多，分别为36株（45．0％）和28株（35．0％），且SCCmecⅢ型对应的spa型以t030（33／36，91．7％）为主，SCCmecⅣ型对应的spa型别以t437（20／28，71．4％）为主。t030型／SCCmecⅢ型MRSA感染患者年龄大于t437／SCCmecⅣ感染的患者（ T＝446．500和607．500， P＜0.01）；前者多来自外科和重症监护病房（ ICU），后者多来自儿科，两种型别感染者的病区分布差异有统计学意义（χ2＝33．724和29．768，P＜0．01）；t030／SCCmecⅢ型MRSA对利福平、红霉素、克林霉素、四环素、左氧氟沙星、莫西沙星、环丙沙星和庆大霉素的耐药性均＞70％；t437／SCCmecⅣ型MRSA除对红霉素、克林霉素和四环素耐药外，对多种非β-内酰胺类抗菌药物均敏感，耐药率基本＜20％。另外，检出携带pvl毒力基因的MRSA 11株（13．8％），以t437-SCCmecⅣ型为主（7株）。结论荆州地区流行的MRSA分子型别众多，但以t030-SCCmecⅢ型和t437-SCCmecⅣ型为主。 t030-SCCmecⅢ型菌株表现出多重耐药的特点，感染对象多为外科和ICU病区的老年患者；t437-SCCmecⅣ型菌株对多种非β-内酰胺类抗菌药物敏感，感染对象主要为儿童和青少年。

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＆amp;nbsp;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 .