金黄色葡萄球菌苯唑西林及红霉素耐药基因多重PCR快速检测

目的 建立金黄色葡萄球菌苯唑西林和红霉素耐药基因的多重PCR快速检测体系,并进行临床应用评价.以了解耐药基因mecA、ermA、ermC在广州地区的流行分布,指导临床合理使用抗生素.方法 全自动仪器鉴定菌株及药敏试验,克林霉素耐药试验检测克林霉素诱导耐药,通过优化PCR反应体系建立多重PCR反应并应用于检测金黄色葡萄球菌耐药基因:mecA、ermA和ermC.结果 成功构建四重PCR快速检测体系,临床评价所分离的124株金黄色葡萄球菌中,mecA、ermA、ermC检出率分别为59.7%、50%、33.9%;克林霉素诱导耐药菌株主要是ermC基因;苯唑西林耐药菌株中均能检测出mecA,红霉素耐药菌株中97.7%携带耐药基因ermA或/及ermC.结论 所构建的多重PCR检测体系为临床实验室提供快速而有效的菌株耐药基因检测手段.mecA、ermA、ermC是本地区分离的金黄色葡萄球菌对苯唑西林和红霉素耐药的主要机制之一.

Rapid detection of oxacillin and erythromycin resistance genes in Staphylococcus aureus using multiplex PCR

OBJECTIVE: To establish a rapid multiplex PCR (MPCR) detection system of oxacillin and erythromycin resistance genes in Staphylococcus aureus (S. aureus) and evaluate the genotype distribution of the genes associated to mecA, ermA and ermC resistance in Guangzhou. METHODS: The S. aureus strains were identified and susceptibility tests were performed using VITEK-60 or PHOENIX-100 system. The inducible resistance to clindamycin of strains with of erythromycin resistance was conducted using D-test, and the MPCR system of for detecting the antibiotic resistance genes was optimized. RESULTS: The MPCR assay for detecting the resistance genes was constructed successfully. According to the results of MPCR, the positivity rates for mecA, ermA and ermC genes among the 124 strains of S. aureus isolated from clinical samples were 56.5%, 50% and 33.9%, respectively. Good correlation was observed between the antibiotic resistance phenotypes and the S. aureus genotypes. mecA were detected in all the methicillin-resistant S. aureus strains, and ermA and/or ermC in 97.7% of the S. aureus strains with erythromycin resistance. CONCLUSION: This MPCR system allows rapid and reliable analysis of antibiotic resistance genotypes of S. aureus isolated from clinical samples. mecA, ermA, and ermC genes are among the predominant genetic determinants for the resistance to oxacillin and erythromycin in S. aureus isolates in Guangzhou.