Department of Molecular Pathology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran.
Department of Clinical Cardiovascular Research, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran.
J Glob Antimicrob Resist. 2017 Sep;10:315-320. doi: 10.1016/j.jgar.2017.06.009. Epub 2017 Jul 20.
Methicillin-resistant Staphylococcus aureus (MRSA) strains are a major cause of hospital-acquired infections and are considered a serious public health concern. MRSA isolates have abundant virulence factors that are the basis for their pathogenicity. The accessory gene regulator (agr) locus co-ordinates the expression of these genes. The aim of this study was to determine the presence and frequency of various virulence genes encoding enterotoxins and adhesins as well as to identify agr specificity groups in MRSA isolates.
This descriptive study included a total of 296 MRSA strains isolated from clinical samples collected in Tehran Heart Center (Tehran, Iran) between October 2004 and March 2013. Following DNA extraction, PCR-based assays were used to evaluate the presence of various virulence genes. IBM SPSS Statistics for Windows v.21.0 was used for statistical analysis.
The results indicated that the most frequent toxin genes were see (120/296; 40.5%), followed by sea (79/296; 26.7%); the other genes were encoded less frequently. The presence of seb and seh was not found in any of the isolates. Furthermore, the most frequent adhesin genes were clfA, spa, cna, map/eap and bbp, found in 281 (94.9%), 275 (92.9%), 267 (90.2%), 265 (89.5%) and 264 (89.2%) isolates, respectively. The majority of isolates belonged to agr group I (53.0%), followed by agr group III (1.4%). None of the isolates belonged to agr group II.
The relatively high frequency of various virulence genes suggests the emergence and pathogenic potential of MRSA isolates containing these genes in the study area.
耐甲氧西林金黄色葡萄球菌（MRSA）菌株是医院获得性感染的主要原因，被认为是严重的公共卫生关注问题。MRSA 分离株具有丰富的毒力因子，这些因子是其致病性的基础。辅助基因调节子（agr）基因座协调这些基因的表达。本研究旨在确定携带各种肠毒素和黏附素编码基因的毒力基因的存在和频率，并鉴定 MRSA 分离株中 agr 特异性组。
本描述性研究共纳入 2004 年 10 月至 2013 年 3 月期间在德黑兰心脏中心（伊朗德黑兰）采集的临床标本中分离的 296 株 MRSA 菌株。提取 DNA 后，采用基于 PCR 的方法评估各种毒力基因的存在情况。采用 IBM SPSS Statistics for Windows v.21.0 进行统计分析。
结果表明，最常见的毒素基因是 see（120/296；40.5%），其次是 sea（79/296；26.7%）；其他基因的编码频率较低。在任何分离株中均未发现 seb 和 seh。此外，最常见的黏附素基因是 clfA、spa、cna、map/eap 和 bbp，分别在 281（94.9%）、275（92.9%）、267（90.2%）、265（89.5%）和 264（89.2%）分离株中发现。大多数分离株属于 agr 组 I（53.0%），其次是 agr 组 III（1.4%）。没有分离株属于 agr 组 II。
各种毒力基因的相对高频率表明，在研究区域中携带这些基因的 MRSA 分离株的出现和致病潜力。
