Motomura Yuka, Miyazaki Motoyasu, Kamada Mitsuhiro, Morimoto Shinichi, Nakamura Yoshihiko, Satho Tomomitsu, Takata Tohru, Kashige Nobuhiro
Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan.
Department of Pharmacy, Fukuoka University Chikushi Hospital, Fukuoka 818-8502, Japan.
Antibiotics (Basel). 2024 Jul 19;13(7):670. doi: 10.3390/antibiotics13070670.
There have been few reports regarding the long-term trends in the genotypes of methicillin-resistant (MRSA) bloodstream isolates. Therefore, this study was performed to investigate the longitudinal trends in the genotypes of MRSA bloodstream isolates obtained from hospitalized patients during a 12-year study period from 2010 to 2021 at a tertiary care university hospital. Over the 12-year period from 2010 to 2021, we conducted a genetic investigation focusing on 245 MRSA strains isolated from the blood of hospitalized patients. The genotypes of the MRSA bloodstream isolates were determined by Staphylococcal Cassette Chromosome (SCC) typing, accessory gene regulator () typing, PCR-based ORF typing (POT), and multilocus sequence typing (MLST). Strains with the same POT type detected in two or more isolates were designated as epidemic clones, while strains without a common POT type were classified as sporadic clones. Until 2015, isolates with SCC II/ II were prevalent, but isolates with SCC IV/ III increased from 2016. A total of 128 strains (52%) were identified as epidemic clones, while 117 strains (48%) were classified as sporadic clones. The detection rate of sporadic clones increased significantly since 2016 ( < 0.05). The epidemic clones were classified into three clusters, with MRSA of clonal complex (CC) 1 being prominent after 2016. This study showed that the genotypes of MRSA bloodstream isolates underwent a shift from SCC II/ II type to SCC IV/ III type, with a notable increase in MRSA of CC1, after 2016. There was a significant increase in the proportion of sporadic strains among the isolates, suggesting the diversification of genotypes.
关于耐甲氧西林金黄色葡萄球菌（MRSA）血流分离株基因型的长期趋势的报道很少。因此，本研究旨在调查2010年至2021年在一家三级医疗大学医院的12年研究期间，从住院患者中获得的MRSA血流分离株基因型的纵向趋势。在2010年至2021年的12年期间，我们对从住院患者血液中分离出的245株MRSA菌株进行了基因研究。通过葡萄球菌盒式染色体（SCC）分型、辅助基因调节因子（）分型、基于PCR的开放阅读框分型（POT）和多位点序列分型（MLST）来确定MRSA血流分离株的基因型。在两个或更多分离株中检测到相同POT类型的菌株被指定为流行克隆，而没有共同POT类型的菌株被分类为散发克隆。直到2015年，SCC II/ II型分离株很普遍，但SCC IV/ III型分离株从2016年开始增加。共有128株（52%）被鉴定为流行克隆，而117株（48%）被分类为散发克隆。自2016年以来，散发克隆的检出率显著增加（<0.05）。流行克隆分为三个簇，2016年后克隆复合体（CC）1的MRSA占主导地位。本研究表明，MRSA血流分离株的基因型从SCC II/ II型转变为SCC IV/ III型，2016年后CC1的MRSA显著增加。分离株中散发病原菌比例显著增加，表明基因型多样化。
