Wuhan University, Zhongnan Hospital, Department of Laboratory Medicine, Wuhan, China.
Peking Union Medical College & Chinese Academy of Medical Sciences, National Center for Cardiovascular Diseases & Fuwai Hospital, Center of Laboratory Medicine, Beijing, China.
Braz J Infect Dis. 2018 Nov-Dec;22(6):487-494. doi: 10.1016/j.bjid.2018.12.001. Epub 2018 Dec 27.
The rate of methicillin-resistant Staphylococcus aureus (MRSA) among the total of S. aureus isolates decreased to 35.3% in 2017 in China. It is unclear whether the molecular characteristics of S. aureus isolates have changed as the rate decreased.
This study aimed to investigate the molecular characteristics and virulence genes profile of S. aureus isolates causing bloodstream infection and analyze the correlation between the prevalence rates of the common sequence types and MRSA.
A total of 112 S. aureus strains from eight hospitals of four cities, including 32 MRSA isolates, were identified and evaluated through multilocus sequence typing, spa typing, and determination of virulence genes.
Twenty-five STs were identified, of which ST5 (21.4%) was the most prevalent, whereas the prevalence of ST239 correlated with the rate of MRSA among all S. aureus isolates. Forty-six spa types were identified, of which t2460 (14.3%) was the most common. clfa, hla, seb, fnbA and hlb were the prevailing virulence genes. 81.3% MRSA and 45.0% methicillin-sensitive S. aureus (MSSA) isolates harbored six or more tested virulence genes. ST5-t2460, seldom noted in bloodborne S. aureus isolates in China, was the most common clone. The prevalence of harboring six or more virulence genes in ST5-t2460 and ST188-t189 were 93.8% and 8.3%, respectively.
ST5-t2460 was the most common clone in S. aureus causing bloodstream infection followed by ST188-t189, which had never been noted in China before. Moreover, ST5-t2460 harbored more virulence genes than ST188-t189, and the prevalence of ST239 clone decreased with the proportion of MRSA among all S. aureus isolates.
2017 年中国金黄色葡萄球菌（S. aureus）分离株中耐甲氧西林金黄色葡萄球菌（MRSA）的比例降至 35.3%。金黄色葡萄球菌分离株的分子特征是否随着该比例的降低而发生变化尚不清楚。
本研究旨在调查引起血流感染的金黄色葡萄球菌分离株的分子特征和毒力基因谱，并分析常见序列型的流行率与 MRSA 之间的相关性。
从中国四个城市的八家医院共鉴定和评估了 112 株金黄色葡萄球菌株，包括 32 株 MRSA 分离株，采用多位点序列分型、spa 分型和毒力基因测定。
共鉴定出 25 种 ST，其中 ST5（21.4%）最为流行，而 ST239 的流行率与所有金黄色葡萄球菌分离株中 MRSA 的比例相关。共鉴定出 46 种 spa 型，其中 t2460（14.3%）最为常见。clfa、hla、seb、fnbA 和 hlb 是主要的毒力基因。81.3%的 MRSA 和 45.0%的甲氧西林敏感金黄色葡萄球菌（MSSA）分离株携带 6 种或更多检测到的毒力基因。在中国血液来源的金黄色葡萄球菌分离株中很少见的 ST5-t2460 是最常见的克隆株。ST5-t2460 携带 6 种或更多毒力基因的比例为 93.8%，ST188-t189 为 8.3%。
ST5-t2460 是引起血流感染的金黄色葡萄球菌最常见的克隆株，其次是 ST188-t189，这在中国以前从未被报道过。此外，ST5-t2460 携带的毒力基因多于 ST188-t189，而 ST239 克隆的流行率随着所有金黄色葡萄球菌分离株中 MRSA 比例的降低而降低。
