金黄色葡萄球菌的药敏表型和耐甲氧西林金黄色葡萄球菌的SCCmec基因分型

Antimicrobial susceptibility phenotypes of Staphylococcus aureus strains and staphylococcal cassette chromosome mec genotypes of methicillin-resistant Staphylococcus aureus strains

目的研究从临床标本中分离的金黄色葡萄球菌（SA）的耐药性、耐甲氧西林金黄色葡萄球菌（MRSA）的发生率及其葡萄球菌盒式染体色mec（SCCmec）基因分型。方法采用纸片琼脂扩散法进行SA耐药性检测及MRSA测定,应用多重聚合酶链反应（PCR）进行SCCmec各基因型及PV杀白细胞素（PVL）基因型的检测。结果 102株SA中检出39株MRSA,检出率为38.2%（39/102）。甲氧西林敏感金黄色葡萄球菌（MSSA）对克林霉素、复方磺胺甲口恶唑、四环素3种抗菌药物耐药率较高,分别为39.7%、31.7%、22.2%;对庆大霉素及喹诺酮类耐药率较低,为6.3%~14.3%。而MRSA对克林霉素、β-内酰胺类抗菌药物100%耐药,对其他药物表现为多重耐药。未检出万古霉素耐药菌株。MRSA菌株的SCCmec基因型以SCCmecⅢ型为主,占71.2%,SCCmecⅣa占10.3%,未检测出PVL基因。结论临床分离的SA中,MRSA耐药率较MSSA高且表现为多重耐药,其SCCmec基因分型主要表现为SCCmecⅢ型,其次是SCCmecⅣa。

Objective To study the drug resistance of Staphylococcus aureus（SA） strains isolated from the clinical specimens,the incidence rate of methicillin-resistant Staphylococcus aureus（MRSA） strains and staphylococcal cassette chromosome mec（SCCmec） genotypes of MRSA strains.Methods The disc agar diffusion test was used to determine the drug resistance of SA and MRSA strains.The multiplex polymerase chain reaction（PCR） was used to detect SCCmec genotypes and Panton-Valentine leukocidin（PVL） gene of MRSA strains.Results 102 SA isolates were collected,of which 39（38.2%） MRSA isolates were discovered.The drug resistance rates of methicillin-sensitive Staphylococcus aureus（MSSA） strains to clindamycin,sulfamethoxazole and tetracycline were 39.7%,31.7% and 22.2% respectively.The drug resistance rates of MSSA strains to gentamicin and quinolone were 6.3%-14.3%.The drug resistance rates of MRSA strains to clindamycin and beta-lactam antibiotics were all 100%,and the majority of MRSA isolates showed multi-drug resistance.The vancomycin-resistant SA isolates had not been discovered.Among all MRSA isolates,the genotype SCCmec Ⅲ was 71.2%,the genotype SCCmec Ⅳa was 10.3%,and PVL gene had not been discovered.Conclusions Among all SA strains isolated from clinical specimens,the MRSA isolates show multi-drug resistance and greater resistance than the MSSA isolates.Among all MRSA isolates,the SCCmec genotype is mainly SCCmecⅢ,which is followed by SCCmecⅣa.