emm1/Sequence Type 28 Strains of Group A Streptococci That Express covR at Early Stationary Phase Are Associated with Increased Growth and Earlier SpeB Secretion
emm1/Sequence Type 28 Strains of Group A Streptococci That Express covR at Early Stationary Phase Are Associated with Increased Growth and Earlier SpeB Secretion
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在早期稳定期表达 covR 的 emm1/序列 28 型 A 组链球菌菌株与生长加快和早期 SpeB 分泌相关
DOI：
10.1128/jcm.00202-09
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发表时间：
2009-10-01
影响因子：
9.4
通讯作者：
Wu, Jiunn-Jong
中科院分区：
文献类型：
--
作者：
Chiang-Ni, Chuan;Zheng, Po-Xing;Wu, Jiunn-Jong
化脓性链球菌（A 组链球菌 [GAS]）是一种多用途的人类病原体，emm1/序列类型 28 (ST28) 是 GAS 感染中最常见的分离类型。 emm1/ST28 菌株与坏死性筋膜炎和链球菌中毒性休克综合征有关。生长期调控是GAS的重要调控机制之一，它控制生长受限阶段的基因表达。 CovRS 是一种双组分调节系统，被认为是链球菌热原性外毒素 B (SpeB) 的调节剂，并且被认为在指数生长期被激活。在本研究中，Northern杂交分析表明，52%的分析GAS菌株在指数期表达covR，但48%的菌株在生长早期稳定期表达covR。在早期稳定期转录 covR 的菌株比另一组菌株表现出更好的生长和更早的 SpeB 表达。多位点序列分型和脉冲场凝胶电泳分析显示，只有 emm1/ST28 菌株（组成克隆簇）在生长早期稳定期表达 covR，这表明 emm1/ST28 菌株具有特殊特征，这可能与其在全球范围内的分布有关。
Streptococcus pyogenes (group A streptococcus [GAS]) is a versatile human pathogen, and emm1/sequence type 28 (ST28) is the most frequently isolated type from GAS infections. The emm1/ST28 strain is associated with necrotizing fasciitis and streptococcal toxic shock syndrome. Growth-phase regulation is one of the important regulatory mechanisms in GAS, which controls gene expression at restricted phases of growth. CovRS, a two-component regulatory system, is considered the regulator of streptococcal pyrogenic exotoxin B ( SpeB) and is thought to be activated in the exponential phase of growth. In the present study, Northern hybridization analysis showed that 52% of the analyzed GAS strains expressed covR at the exponential phase, but 48% of the strains expressed covR at the early stationary phase of growth. Strains transcribing covR at the early stationary phase showed better growth and earlier SpeB expression than the other group of strains. Multilocus sequence typing and pulsed-field gel electrophoresis analysis showed only emm1/ST28 strains (which comprise a clonal cluster) were expressing covR at the early stationary phase of growth, indicating that emm1/ST28 strains have special characteristics which may be related to their worldwide distribution.