Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama, Tokyo 208-0011, Japan.
J Antimicrob Chemother. 2011 Nov;66(11):2460-4. doi: 10.1093/jac/dkr352. Epub 2011 Aug 26.
Although group B Streptococcus (GBS; i.e. Streptococcus agalactiae) has been considered to be uniformly susceptible to β-lactams, GBS isolates with reduced penicillin susceptibility (PRGBS) have been reported from Japan and North America. In this study, PRGBS from Japan were characterized by multilocus sequence typing (MLST) and the results compared with data on PRGBS reported from the USA.
Twenty-eight clinical isolates of PRGBS recovered in Japan (including 22 isolates previously analysed by PFGE) were analysed by MLST and eBURST (http://eburst.mlst.net/).
Twenty-three isolates were found to belong to the sequence type 1 (ST1) group (11 ST458, 7 ST1, 3 ST297, 1 ST358 and 1 ST4), while the remaining 5 isolates formed the ST23 group. Among 11 ST458 and 7 ST1 isolates, 9 and 4 were serotype VI, respectively, indicating a probable correlation between the ST1 group and serotype VI for PRGBS in Japan.
PRGBS in Japan could be classified into at least two ST groups, ST1 and ST23, which are genetically different from the ST19 PRGBS isolated in the USA, though five allele variations were seen between ST1 and ST19, implying a slight genetic relatedness.
尽管 B 群链球菌（GBS；即无乳链球菌）被认为对β-内酰胺类药物普遍敏感，但已在日本和北美报告了对青霉素敏感性降低的 GBS 分离株（PRGBS）。在本研究中，通过多位点序列分型（MLST）对来自日本的 PRGBS 进行了表征，并将结果与来自美国的 PRGBS 报告数据进行了比较。
对日本分离的 28 株临床 PRGBS 分离株（包括先前通过 PFGE 分析的 22 株）进行了 MLST 和 eBURST（http://eburst.mlst.net/）分析。
23 株被鉴定为 1 型（ST1）组（11 株 ST458、7 株 ST1、3 株 ST297、1 株 ST358 和 1 株 ST4），而其余 5 株形成 ST23 组。在 11 株 ST458 和 7 株 ST1 分离株中，分别有 9 株和 4 株为血清型 VI，表明日本 PRGBS 中 ST1 组与血清型 VI 之间可能存在相关性。
日本的 PRGBS 可分为至少 ST1 和 ST23 两个 ST 组，与美国分离的 ST19 PRGBS 在遗传上不同，尽管在 ST1 和 ST19 之间观察到 5 个等位基因变异，表明存在轻微的遗传相关性。
