社区2型糖尿病人群鼻定植耐甲氧西林金黄色葡萄球菌的分子分型及耐药性

Molecular typing and antibiotic resistance of methicillin-resistant Staphylococcus aureus isolated from nasal swabs among patients with type 2 diabetes in community

目的 了解社区2型糖尿病人群鼻定植耐甲氧西林金黄色葡萄球菌（MRSA）的分子特征及耐药性.方法 对2014年4月到6月期间收集自佛山市里水镇11个社区的417例2型糖尿病患者的鼻拭子样本进行金黄色葡萄球菌的分离鉴定,采用头孢西丁纸片扩散法和mecA基因聚合酶链反应（PCR）法对分离的菌株进行MRSA鉴定,利用多重PCR对MRSA进行葡萄球菌染色体mec盒（SCCmec）分型,根据MRSA的7个管家基因序列进行多位点序列（MLST）分型（ST型）,使用K-B纸片扩散法分析MRSA的耐药性.结果 417份样本中分离得22株MRSA,SCCmec分型有Ⅰ型1株（4.5%）、Ⅱ型3株（13.6%）、Ⅲ型3株（13.6%）、Ⅳ型6株（27.3%）、Ⅴ型4株（18.2%）、未分型5株（22.8%）.MLST分型获得16种ST型,70%的ST型为各克隆复合体的始祖ST型.22株MRSA对红霉素、替考拉宁、克林霉素、莫西沙星、妥布霉素都具有较高的耐药率（分别为81.8%、59.1%、59.1%、36.4%和31.8%）,除1株SCCmecⅣ型外,所有的MRSA均对利奈唑胺无耐药,MRSA的多重耐药率为68.2%.结论 社区2型糖尿病人群鼻前庭定植有MRSA菌株,定植的MRSA基因变异度低,进化稳定,呈多重耐药状态,利奈唑胺宜作为首选药物.

jective To determine the molecular characteristics and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus （MRSA） isolated from nasal swabs among patients with type 2 diabetes in community. Methods Nasal swabs were collected from 417 patients with type 2 diabetes in 11 communities of Lishui Town, Foshan City, from April 2014 to June 2014. Staphylococcus aureus was determined after bacteria isolation and identification. Cefoxitin disk diffusion test and mecA gene polymerase chain reaction （PCR） assay were applied to detect MRSA. The staphylococcal cassette chromosome mec （SCCmec） typing of MRSA was conducted by multiplex PCR assay and the sequence type （ST） typing of MRSA was determined by multilocus sequence typing （MLST） based on the sequence of 7 housekeeping genes of MRSA. The antibiotic susceptibility of MRSA was tested by K-B disk diffusion.Results A total of 22 MRSA strains were isolated from the nasal swabs of 417 patients, including 1 strain of SCCmecⅠ （4.5%）, 3 strains of SCCmecⅡ （13.6%）, 3 strains of SCCmecⅢ （13.6%）, 6 strains of SCCmec Ⅳ （27.3%）, 4 strains of SCCmecV （18.2%） and 5 strains non-typeable （22.8%）. Sixteen STs were found with MLST, of which 70% were ancestral ST for each clonal complex. MRSA isolates had high resistance rates to erythromycin, teicoplanin, clindamycin, moxifloxacin, tobramycin （81.8% , 59.1% , 59.1% , 36.4% and 31.8%, respectively）, and all of MRSA isolates but 1 strain of SCCmec Ⅳ were sensitive to linezolid. And 68.2% of MRSA isolates were multi-drug resistant bacteria. Conclusions MRSA colonization is found in noses of patients with type 2 diabetes in community. The gene variation of MRSA isolates is low and its evolution is stable. Linezolid should be the prior choice for community infection of MRSA.