Department of General Medicine and Emergency Care, Toho University Graduate School of Medicine, Tokyo, Japan; Department of General Medicine and Emergency Care, Toho University Omori Medical Centre, Tokyo, Japan.
Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Tokyo, Japan.
J Hosp Infect. 2023 Sep;139:141-149. doi: 10.1016/j.jhin.2023.05.014. Epub 2023 Jun 8.
The emergence of novel genomic-type clones, such as community-associated meticillin-resistant Staphylococcus aureus (MRSA) and livestock-associated MRSA, and their invasion into hospitals have become major concerns worldwide; however, little information is available regarding the prevalence of MRSA in Japan. Whole-genome sequencing (WGS) has been conducted to analyse various pathogens worldwide. Therefore, it is important to establish a genome database of clinical MRSA isolates available in Japan.
A molecular epidemiological analysis of MRSA strains isolated from bloodstream-infected patients in a Japanese university hospital was conducted using WGS and single-nucleotide polymorphism (SNP) analysis. Additionally, through a review of patients' clinical characteristics, the effectiveness of SNP analysis as a tool for detecting silent nosocomial transmission that may be missed by other methods was evaluated in diverse settings and various time points of detection.
Polymerase-chain-reaction-based staphylococcal cassette chromosome mec (SCCmec) typing was performed using 135 isolates obtained between 2014 and 2018, and WGS was performed using 88 isolates obtained between 2015 and 2017.
SCCmec type II strains, prevalent in 2014, became rare in 2018, whereas the prevalence of SCCmec type IV strains increased from 18.75% to 83.87% of the population, and became the dominant clones. Clonal complex (CC) 5 CC8 and CC1 were detected between 2015 and 2017, with CC1 being dominant. In 88 cases, SNP analyses revealed nosocomial transmissions among 20 patients which involved highly homologous strains.
Routine monitoring of MRSA by whole-genome analysis is effective not only for gaining knowledge regarding molecular epidemiology, but also for detecting silent nosocomial transmission.
新型基因组克隆的出现，如社区相关耐甲氧西林金黄色葡萄球菌（MRSA）和畜群相关 MRSA，以及它们入侵医院，已成为全球关注的主要问题。然而，有关日本 MRSA 流行率的信息很少。全基因组测序（WGS）已用于分析全球各种病原体。因此，建立日本临床分离的 MRSA 基因组数据库非常重要。
使用 WGS 和单核苷酸多态性（SNP）分析对从日本一家大学医院血流感染患者中分离的 MRSA 菌株进行分子流行病学分析。此外，通过回顾患者的临床特征，评估 SNP 分析作为一种检测其他方法可能遗漏的沉默医院内传播的工具的有效性，这种方法在不同的环境和不同的检测时间点都有效果。
使用 2014 年至 2018 年间获得的 135 株分离株进行基于聚合酶链反应的葡萄球菌盒染色体 mec（SCCmec）分型，使用 2015 年至 2017 年间获得的 88 株分离株进行 WGS。
2014 年流行的 SCCmec 型 II 株在 2018 年变得罕见，而 SCCmec 型 IV 株的流行率从人群的 18.75%增加到 83.87%，成为主要克隆。2015 年至 2017 年间检测到克隆复合体（CC）5 CC8 和 CC1，CC1 占主导地位。在 88 例中，SNP 分析显示 20 例患者存在医院内传播，涉及高度同源菌株。
通过全基因组分析对 MRSA 进行常规监测，不仅有助于了解分子流行病学，还能检测沉默的医院内传播。
