天津市耐甲氧西林葡萄球菌的耐药状况和基因分型

目的 分析耐甲氧西林葡萄球菌的耐药状况及耐药基因,了解目前葡萄球菌耐药的流行病学特征.方法 对临床分离的138株葡萄球菌进行耐药性检测,用聚合酶链反应（PCR）检测mecA耐药基因,并结合两种多重PCR方法对mecA阳性菌株进行葡萄球菌染色体mec盒基因（SCCmec）分型.结果 138株葡萄球菌中,金黄色葡萄球菌65株,其中耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus,MRSA）7株,阳性率为10.8%;凝固酶阴性葡萄球菌73株,其中耐甲氧西林凝固酶阴性葡萄球菌（methicillin-resistant coagulase negative Staphylococcus,MRCNS）44株,阳性率为60.3%,二者差异具有统计学意义（x2=37.05,P＜0.01）.所有菌株对万古霉素和呋哺妥因均敏感.经PCR检测52株葡萄球菌mecA基因阳性,阳性率为37.7%（52/138）,SCCmec分型发现Ⅰ型16株,Ⅱ型1株,Ⅲ型13株,Ⅳ型9株,Ⅴ型4株.结论 耐甲氧西林葡萄球菌的耐药情况日益严重,临床上MRCNS比MRSA更常见,SCCmec Ⅰ型和Ⅲ型菌株为主要流行菌株.

Drug resistance and genotype of methicillin-resistant Staphylococcus in Tianjin

Objective To investigate the drug resistance and genotype of methicillin-resistant Staphylococcus （MRS）, and to study the epidemiology of drug resistance in Staphylococcus. Methods Drug susceptibility tests were performed for 138 Staphylococcus strains clinically isolated, and mecA gene was detected with PCR. For mecA positive strains, Staphylococcal cassette chromosome mec （SCCmec） gene was detected by two multiplex PCR assays. Results Seven （10.8%） out of 65 Staphylococcus aureus strains were methicillin-resistant Staphylococcus aureus （MRSA） strains, and 44 （60.3%） out of 73 coagulase negative Staphylococcus strains were methicillin-resistant coagulase negative Staphylococcus （MRCNS）strains. There was statistical significance on the difference of isolation rates （x2 = 37. 05, P 〈0.01）. No vancomycin or nitrofurantoin resistant strain was found. There were 52 （52/138, 37.7%） mecA positive strains, including 16 SCCmec type Ⅰ strains, 1 type Ⅱ strain, 13 type Ⅲ strains, 9 type Ⅳ strains and 4 type Ⅴ strains. Conclusions Drug resistance in MRS is increasingly serious. MRCNS strains are more popular than MRSA in clinic, and SCCmec Ⅰ and Ⅲ may account for most infections.