Aung Meiji Soe, Urushibara Noriko, Kawaguchiya Mitsuyo, Ohashi Nobuhide, Hirose Mina, Kudo Kenji, Ito Masahiko, Kobayashi Nobumichi
Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
J Glob Antimicrob Resist. 2025 Jan;40:1-7. doi: 10.1016/j.jgar.2024.11.004. Epub 2024 Nov 26.
Staphylococcus argenteus, a newly described species of coagulase-positive Staphylococcus, was first identified in clinical isolates in northern Japan in 2019. The aim of the present study was to clarify the trends in the epidemiological features and antimicrobial resistance traits of S. argenteus in the recent years.
S. argenteus isolates from various clinical specimens were screened using MALDI-TOF and genotyped using the multilocus sequence typing scheme. Antimicrobial susceptibility was determined using broth microdilution test and resistance genes were detected by multiplex/uniplex PCR. Nucleotide sequences of haemolysin genes (hla, hlb, hld, and hlg) were determined and analysed in some isolates.
From August 2020 to December 2023, 210 isolates were identified as S. argenteus. The ratio of S. argenteus to Staphylococcus aureus clinical isolates was 0.0045, showing a slightly decreasing trend compared to what was previously reported (2019.8-2020.7). Three genotypes, ST1223-coa-XV, ST2198-coa-XIV, and ST2250-coa-XId were identified, with ST2250 being dominant (49%) and exhibiting an increasing trend. S. argenteus isolates were almost susceptible to antimicrobials examined, while ST2198 isolates showed higher resistance rates to ampicillin, macrolides, and aminoglycosides than other clones, harbouring blaZ, msrA, and aac(6')-Ie-aph(2″)-Ia. Only eight isolates (4-ST2250, 3-ST1223, and 1-ST2198) did not show haemolysis on blood agar plates. These isolates had intact haemolysin genes and promoter regions; however, a novel deletion mutation in hlg-component A was detected in some haemolytic and non-haemolytic isolates.
The present study revealed the epidemiological trend of S. argenteus clones in northern Japan, along with the occurrence of non-haemolytic isolates with intact haemolysin genes.
银色葡萄球菌是一种新描述的凝固酶阳性葡萄球菌，于2019年在日本北部的临床分离株中首次被鉴定出来。本研究的目的是阐明近年来银色葡萄球菌的流行病学特征和抗菌药物耐药性特征的变化趋势。
使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）对从各种临床标本中分离出的银色葡萄球菌进行筛选，并使用多位点序列分型方案进行基因分型。采用肉汤微量稀释法测定抗菌药物敏感性，并通过多重/单重聚合酶链反应（PCR）检测耐药基因。对部分分离株的溶血素基因（hla、hlb、hld和hlg）的核苷酸序列进行了测定和分析。
2020年8月至2023年12月期间，共鉴定出210株银色葡萄球菌。银色葡萄球菌与金黄色葡萄球菌临床分离株的比例为0.0045，与之前报道的比例（2019.8 - 2020.7）相比呈略有下降趋势。鉴定出三种基因型，即ST1223-coa-XV、ST2198-coa-XIV和ST2250-coa-XId，其中ST2250占主导地位（49%）且呈上升趋势。银色葡萄球菌分离株对所检测的抗菌药物几乎均敏感，而ST2198分离株对氨苄西林、大环内酯类和氨基糖苷类的耐药率高于其他克隆株，携带blaZ、msrA和aac(6')-Ie-aph(2″)-Ia基因。只有8株分离株（4株ST2250、3株ST1223和1株ST2198）在血琼脂平板上不显示溶血现象。这些分离株具有完整的溶血素基因和启动子区域；然而，在一些溶血和不溶血分离株中检测到hlg组分A中的一种新型缺失突变。
本研究揭示了日本北部银色葡萄球菌克隆株的流行病学趋势，以及具有完整溶血素基因的不溶血分离株的出现情况。
