School of Medicine, China Medical University, Taichung, Taiwan; Department of Pediatric Infectious Diseases, China Medical University Children's Hospital, Taichung, Taiwan.
Department of Laboratory Medicine, Linkou Chang-Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Kwei-Shan, Taoyuan, Taiwan.
J Microbiol Immunol Infect. 2019 Feb;52(1):81-89. doi: 10.1016/j.jmii.2017.11.007. Epub 2017 Dec 30.
Group B Streptococcus (GBS) is an important invasive pathogen in neonates, pregnant women and the elderly. Serotype VI GBS, which has been rarely reported globally, has emerged as a significant pathogen in Asia. However, traditional serologic latex agglutination (LA) methods may fail to type isolates that lack of or low expression of CPS.
A total of 104 GBS strains were analyzed by MALDI-TOF MS. Multiplex PCR and multilocus sequence typing (MLST) were also performed to confirm their strains. The protein markers were purified with gel electrophoresis and LC-column, followed by identification with nanoLC-MS/MS analysis.
Protein peak of 6251-Da was appeared in most (20/24, 92%) serotypes VI (94% ST-1 or single locus variant of ST-1), and protein peak of 6891-Da was appeared in most serotypes III (15/18, 83%) and Ib (19/23, 83%) strains. The protein peak of 6251-Da and 6891-Da were identified as CsbD family protein and UPF0337 protein gbs0600, respectively.
The protein peak of 6251 Da may play a role of emergence of ST-1 clone, serotype VI GBS in central Taiwan and could be useful in rapid identifying invasive serotype VI from III isolates, which is hardly achieved by LA.
B 群链球菌（GBS）是新生儿、孕妇和老年人中一种重要的侵袭性病原体。全球鲜有报道的血清型 VI GBS 已成为亚洲的重要病原体。然而，传统的乳胶凝集（LA）血清学方法可能无法对缺乏或低表达荚膜多糖（CPS）的分离株进行分型。
采用 MALDI-TOF MS 对 104 株 GBS 菌株进行分析。还进行了多重 PCR 和多位点序列分型（MLST）以确认其菌株。采用凝胶电泳和 LC 柱纯化蛋白标志物，然后进行 nanoLC-MS/MS 分析鉴定。
大多数血清型 VI（94% ST-1 或 ST-1 的单一基因座变异体，20/24，92%）菌株出现 6251-Da 蛋白峰，大多数血清型 III（15/18，83%）和 Ib（19/23，83%）菌株出现 6891-Da 蛋白峰。6251-Da 和 6891-Da 蛋白峰分别被鉴定为 CsbD 家族蛋白和 UPF0337 蛋白 gbs0600。
6251-Da 蛋白峰可能在台湾中部 ST-1 克隆、血清型 VI GBS 的出现中发挥作用，可用于快速鉴定 LA 难以实现的侵袭性血清型 VI 与 III 分离株。
