中国南方大陆地区婴儿中 B 群链球菌分离株的分子特征。
Molecular characteristics of group B Streptococcus isolates from infants in southern mainland China.
机构信息
Clinical Laboratory, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Clinical Laboratory, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, 510095, Guangdong, China.
出版信息
BMC Infect Dis. 2019 Sep 18;19(1):812. doi: 10.1186/s12879-019-4434-0.
BACKGROUND
Invasive group B Streptococcus (GBS) disease in Chinese infants has gradually gained attention in recent years, but the molecular epidemiology of the pathogen is still not well known.
METHODS
This multicenter study retrospectively investigated distribution of capsular serotypes, sequence types (STs), and hypervirulent GBS adhesin gene (hvgA) in clinical GBS isolates that caused invasive disease in infants aged < 3 months of age in southern mainland China between January 2013 and June 2016. Genes for antibiotic resistance to tetracycline, erythromycin, and clindamycin were also examined.
RESULTS
From a total of 93 GBS isolates taken from 34 early-onset disease (EOD, 0-6 days after birth) and 59 late-onset disease (LOD, 7-89 days after birth) cases, four serotypes were identified: serotypes III (79.6%), Ib (12.9%), Ia (4.3%), and V (3.2%). Serotype III accounted for 73.5% of EOD and 83.1% of LOD and was responsible for 75.5% of cases involving meningitis. Fifteen STs were found, with the majority being ST17 (61.3%), ST12 (7.5%), ST19 (7.5%), and others (23.7%). 96.8% of STs belonged to only five clonal complexes (CCs): CC17 (64.5%), CC10 (12.9%), CC19 (9.7%), CC23 (6.5%), and CC1 (3.2%). The hvgA gene was detected in 66.7% of GBS isolates and 95% of CC17 isolates, all of which were serotype III except one serotype Ib/CC17 isolate. A large proportion of GBS isolates were found to be resistant to tetracycline (93.5%), clindamycin (65.5%), and erythromycin (60.2%). Genes of tetO (74.7%) and tetM (46.0%) were found in tetracycline resistant isolates, linB (24.6%) in clindamycin resistant isolates, and ermB (87.5%) and mefA (3.6%) in erythromycin resistant isolates.
CONCLUSION
Our results reveal higher prevalence of serotype III, ST17, CC17, hvgA expressing, and antibiotic resistant GBS isolates than previously reported in southern mainland China. This study provides guidance for appropriate measures of prevention and control to be taken in the future.
背景
近年来，侵袭性 B 组链球菌（GBS）疾病在中国婴儿中逐渐受到关注，但该病原体的分子流行病学仍知之甚少。
方法
本多中心研究回顾性调查了 2013 年 1 月至 2016 年 6 月期间中国南方大陆地区 3 月龄以下婴儿侵袭性疾病中临床分离的 GBS 菌株的荚膜血清型、序列型（ST）和高毒力 GBS 黏附素基因（hvgA）的分布。还检测了对抗生素四环素、红霉素和克林霉素的耐药基因。
结果
从 34 例早发性疾病（EOD，出生后 0-6 天）和 59 例晚发性疾病（LOD，出生后 7-89 天）的 93 例 GBS 分离株中，鉴定出 4 种血清型：血清型 III（79.6%）、Ib（12.9%）、Ia（4.3%）和 V（3.2%）。血清型 III 占 EOD 的 73.5%和 LOD 的 83.1%，并导致 75.5%的脑膜炎病例。发现 15 种 ST，其中大多数为 ST17（61.3%）、ST12（7.5%）、ST19（7.5%）和其他（23.7%）。96.8%的 ST 仅属于五个克隆群（CC）：CC17（64.5%）、CC10（12.9%）、CC19（9.7%）、CC23（6.5%）和 CC1（3.2%）。66.7%的 GBS 分离株和 95%的 CC17 分离株检测到 hvgA 基因，除 1 株 Ib/CC17 血清型分离株外，均为血清型 III。很大一部分 GBS 分离株对四环素（93.5%）、克林霉素（65.5%）和红霉素（60.2%）耐药。在四环素耐药株中发现 tetO（74.7%）和 tetM（46.0%）基因，克林霉素耐药株中发现 linB（24.6%），红霉素耐药株中发现 ermB（87.5%）和 mefA（3.6%）。
结论
本研究结果显示，与中国南方大陆地区以往报道相比，血清型 III、ST17、CC17、表达 hvgA 和抗生素耐药的 GBS 分离株的流行率更高。本研究为今后采取适当的预防和控制措施提供了指导。
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