Maeda Ryuto, Kobayashi Hidetomo, Higashidani Mami, Matsuhisa Tetsuaki, Sawa Akihiro, Miyake Katsushi, Tayama Yoshitaka, Kimura Kouji, Itoh Hiroyuki, Okano Taichi, Seike Soshi, Yamanaka Hiroyasu
Research Center for Pharmaceutical Health Care and Sciences, Faculty of Pharmaceutical Sciences, Hiroshima International University, Hiro-Koshingai, Kure, Hiroshima 737-0112, Japan.
National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Aoyama-cho, Kure, Hiroshima 737-0023, Japan.
Access Microbiol. 2022 Feb 25;4(2):000319. doi: 10.1099/acmi.0.000319. eCollection 2022.
Methicillin-resistant (MRSA) is one of the major pathogens of nosocomial infections throughout the world. In the medical field, it is extremely important to this pathogen's trends when considering infection control.
HYPOTHESIS/GAP STATEMENT: We hypothesized that clarifying the characteristics of clinically isolated MRSA would contribute to infection control and proper use of antimicrobial agents against MRSA.
The purpose of this study is to elucidate the genetic and biological characteristics of the MRSA isolates found at our hospital and to reveal changes in the spread of this pathogen in the local area where we live.
Pulse-field gel electrophoresis (PFGE) and polymerase chain reaction were used for the genetic analyses of MRSA isolates. Toxin production by each isolate was examined using toxin-specific detection systems.
During the 3 years from 2017 through 2019, over 1000 MRSA strains were isolated at our hospital. Genomic analysis of 237 of these clinical isolates by PFGE revealed 12 PFGE types (types A to L), each consisting of five or more MRSA clinical strains with over 80% genetic similarity. Examination of the SCC genotypes found that 219 of 237 isolated MRSA strains (approximately 92%) were SCC genotype II or IV and that only four of the isolates carried the Panton-Valentine leukocidin (PVL) gene. Examination of the toxin production of the isolates using staphylococcal enterotoxin detection kits found that most isolates carrying the SCC genotype II produced enterotoxin B and/or C, and that most isolates carrying the SCC genotype IV produced enterotoxin A.
The present results revealed that MRSA isolates with common properties were isolated at certain rates throughout the 3 year study period, suggesting that relatively specific MRSA clones may have settled in the local area around our hospital. We also examine the relationship between antimicrobial usage over time and changes in MRSA isolation rates.
耐甲氧西林金黄色葡萄球菌（MRSA）是全球医院感染的主要病原体之一。在医学领域，考虑感染控制时了解这种病原体的趋势极为重要。
假设/差距陈述：我们假设阐明临床分离的MRSA的特征将有助于感染控制和合理使用抗MRSA抗菌药物。
本研究的目的是阐明我院分离的MRSA菌株的遗传和生物学特征，并揭示该病原体在我们所在地区传播的变化情况。
采用脉冲场凝胶电泳（PFGE）和聚合酶链反应对MRSA分离株进行遗传分析。使用毒素特异性检测系统检测各分离株的毒素产生情况。
在2017年至2019年的3年期间，我院分离出1000多株MRSA菌株。通过PFGE对其中237株临床分离株进行基因组分析，发现了12种PFGE类型（A至L型），每种类型由5株或更多株遗传相似性超过80%的MRSA临床菌株组成。对SCC基因型的检测发现，237株分离的MRSA菌株中有219株（约92%）为SCC基因型II或IV，只有4株携带杀白细胞素（PVL）基因。使用葡萄球菌肠毒素检测试剂盒检测分离株的毒素产生情况，发现大多数携带SCC基因型II的分离株产生肠毒素B和/或C，大多数携带SCC基因型IV的分离株产生肠毒素A。
目前的结果表明，在整个3年的研究期间，具有共同特性的MRSA分离株以一定比例被分离出来，这表明相对特定的MRSA克隆可能已在我院周边地区定殖。我们还研究了随时间变化的抗菌药物使用情况与MRSA分离率变化之间的关系。
