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Abstract：
Background Methicillin-resistant Staphylococcus aureus (MRSA) is a widely recognized multidrug-resistant bacteria presenting a major therapeutic challenge to clinicians. Staphylococcus aureus possesses a number of pathogenicity factors that attribute to the severity of infections. This study was undertaken to investigate the common virulence genes in clinical isolates of Staphylococcus aureus , determine their antimicrobial susceptibility profile, and to characterize the staphylococcal cassette chromosome mec (SCCmec) types among MRSA in a tertiary care center. Materials and Methods A total of 133 clinical isolates were included in this study. Susceptibility to various antibiotics was determined by disc diffusion method. Methicillin resistance was screened using cefoxitin disc; m ecA and mecC genes were detected using polymerase chain reaction (PCR). PCR was done to detect 12 virulence factors such as hla , hlb , fnbA , fnbB , sea , seb , sec , icaA , clfA , tst , pvl, and eta . SCCmec typing was done by multiplex PCR. Results Of the 133 clinical isolates, 54 (40.6%) were MRSA. The most common virulence gene detected was hlb (61.6%), hla (39%), and fnbA (37%). SCCmec type I was the most predominant. Mortality rate of 6.7% was observed among patients with staphylococcal infections. Univariate analysis of mortality associated virulence genes did not reveal any significant association between virulence genes and mortality. Conclusion The distribution of virulence genes is similar in both MRSA and methicillin-sensitive Staphylococcus aureus . MRSA belongs to the SCCmec types I to IV. Possession of multiple virulence factors and multidrug resistance profile makes Staphylococcus aureus a formidable pathogen in clinical settings.
摘要：
背景技术耐甲氧西林金黄色葡萄球菌(MRSA)是一种广泛认可的多重耐药细菌,对临床医生提出了重大的治疗挑战。金黄色葡萄球菌具有许多致病因子，这些致病因子归因于感染的严重程度。本研究旨在调查金黄色葡萄球菌临床分离株中常见的毒力基因。确定他们的抗菌药物敏感性，并在三级护理中心的MRSA中表征葡萄球菌盒染色体mec（SCCmec）类型。材料与方法本研究共纳入133个临床分离株。通过圆盘扩散法测定对各种抗生素的敏感性。使用头孢西丁圆盘筛选甲氧西林抗性；使用聚合酶链反应（PCR）检测mecA和mecC基因。进行PCR以检测12种毒力因子，例如hla，hlb,fnba,fnbB,海,seb,sec,icaA,clfA,tst,pvl,还有eta.通过多重PCR进行SCCmec分型。结果在133个临床分离株中，54例(40.6%)为MRSA。检测到的最常见的毒力基因是hlb（61.6％），hla（39%），和fnba（37%）。SCCmecI型是最主要的。葡萄球菌感染患者的死亡率为6.7％。死亡率相关毒力基因的单变量分析未揭示毒力基因与死亡率之间的任何显著关联。结论MRSA和甲氧西林敏感金黄色葡萄球菌毒力基因分布相似。MRSA属于SCCmec类型I至IV。拥有多种毒力因子和多药耐药性使金黄色葡萄球菌成为临床环境中的强大病原体。
