Zhao Huanqiang, Xu Su, Yang Han, He Chunyan, Xu Xiaogang, Hu Fupin, Shu Wen, Gong Fang, Zhang Chuanling, Liu Qingzhong
Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
Front Microbiol. 2019 Jun 19;10:1388. doi: 10.3389/fmicb.2019.01388. eCollection 2019.
The toxic shock syndrome toxin-1 (TSST-1), encoded by gene, has been proposed to cause staphylococcal toxic shock syndrome (TSS) in a susceptible host, which highlights the need to evaluate the level of gene expression and molecular genetic characteristics of the -positive isolates. A total of 916 isolates collected from seven hospitals in China were screened for the gene. The positive isolates were characterized by , SCC, PFGE, and typing. Representative strains were also subjected to MLST typing. qRT-PCR was used to quantify and major virulence regulator genes expression. We also sequenced the regions of promoter and open reading frame (ORF) of to investigate whether they correlate with the variation in expression. We found 208 (22.7%) of surveyed isolates including 198 (29.8%) of MRSA and 10 (4.0%) of MSSA isolates harbored the gene. The most common clone among positive MRSA isolates belonged to ST5 (CC5)-2-t002-SCCII. The amount of mRNA varied 8.4-folds among clinical isolates. Sequencing the promoter revealed a base T deletion in high expressed isolates. As for major virulence regulators, , and in four differentially expressed strains were detected to be highly expressed, respectively. Our study revealed high prevalence of ST5 (CC5)-2-t002-SCCII clone among positive MRSA in hospitals from China. The levels of expression among clinical isolates varied, which may be associated with promoter and variations in specific virulence regulators.
由基因编码的中毒性休克综合征毒素-1（TSST-1）被认为可在易感宿主中引发葡萄球菌中毒性休克综合征（TSS），这凸显了评估基因表达水平以及该基因阳性分离株分子遗传特征的必要性。对从中国七家医院收集的总共916株分离株进行了该基因的筛查。通过、SCC、PFGE和分型对该基因阳性分离株进行了特征分析。代表性菌株也进行了多位点序列分型（MLST）。采用qRT-PCR定量分析和主要毒力调节基因的表达。我们还对的启动子区域和开放阅读框（ORF）进行了测序，以研究它们是否与表达变化相关。我们发现，在所调查的分离株中有208株（22.7%）携带该基因，其中包括198株（29.8%）耐甲氧西林金黄色葡萄球菌（MRSA）和10株（4.0%）甲氧西林敏感金黄色葡萄球菌（MSSA）分离株。该基因阳性MRSA分离株中最常见的克隆属于ST5（CC5）-2-t002-SCCII。临床分离株中mRNA的量相差8.4倍。对启动子进行测序发现，高表达分离株中有一个碱基T缺失。至于主要毒力调节因子，在四株表达差异的菌株中分别检测到、和高表达。我们的研究揭示了中国医院中该基因阳性MRSA中ST5（CC5）-2-t002-SCCII克隆的高流行率。临床分离株中的表达水平各不相同，这可能与启动子以及特定毒力调节因子的变异有关。
