Lu Binghuai, Chen Xingchun, Wang Junrui, Wang Duochun, Zeng Ji, Li Yi, Li Dong, Zhu Fengxia, Cui Yanchao, Huang Lei
Department of Laboratory Medicine, Civil Aviation General Hospital, Beijing 100123, China.
Department of Laboratory Medicine, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021, China.
Diagn Microbiol Infect Dis. 2016 Dec;86(4):351-357. doi: 10.1016/j.diagmicrobio.2016.08.023. Epub 2016 Aug 28.
Group B streptococcus (GBS) is an increasing pathogen threat to newborns and adults with immunodepressive diseases. Here, a total of 193 GBS, including 51 invasive and 142 noninvasive isolates, were collected from the patients with infections in 7 tertiary hospitals from 5 cities in China during the year 2008 to 2015. The strains of GBS were characterized by classical and molecular techniques for capsular polysaccharide serotyping, genes for pilus island (PI) and α-like protein (alp), and antibiotic resistance profiling. Of 193 isolates, the predominant serotypes were III (45.6%) and Ia (18.7%). All strains carried at least 1 PI gene. The combination of PI-2b and PI-1 was present in 46.1% isolates, followed by PI-2a alone (80, 41.5%) and PI-2b alone (23, 11.9%). The most prevalent alp gene was rib (87, 45.1%), followed by α-C (47, 24.4%), ε (33, 17.1%), alp2/3 (7, 3.6%) and alp4 (2, 1.0%), respectively. The clonal relationships between strains were investigated using multilocus sequence typing. The strains were distinguished into 26 individual sequence typing, and further clustered into 6 clonal complexes. A significant association was noted between the distributions of alp genes, serotyping and PI profiles, such as serotype III-rib-PI+PI-2a, Ib-α-C, and Ia-ε-PI-2a. No penicillin-resistant strains were detected, and 74.1%, 64.2%, and 68.9% were resistant to erythromycin, clindamycin, and tetracycline, respectively. The infective GBS isolates in China demonstrated epidemical features.
B族链球菌（GBS）对新生儿和患有免疫抑制性疾病的成年人构成了日益严重的病原体威胁。在此，2008年至2015年期间，从中国5个城市的7家三级医院的感染患者中总共收集了193株GBS，其中包括51株侵袭性分离株和142株非侵袭性分离株。采用经典和分子技术对GBS菌株进行了荚膜多糖血清分型、菌毛岛（PI）和α样蛋白（alp）基因以及抗生素耐药性分析。在193株分离株中，主要血清型为III型（45.6%）和Ia型（18.7%）。所有菌株至少携带1个PI基因。PI-2b和PI-1的组合存在于46.1%的分离株中，其次是单独的PI-2a（80株，41.5%）和单独的PI-2b（23株，11.9%）。最常见的alp基因是rib（87株，45.1%），其次分别是α-C（47株，24.4%）、ε（33株，17.1%）、alp2/3（7株，3.6%）和alp4（2株，1.0%）。使用多位点序列分型研究了菌株之间的克隆关系。这些菌株被分为26个单倍型，并进一步聚类为6个克隆复合体。在alp基因分布、血清分型和PI谱之间发现了显著关联，如血清型III-rib-PI+PI-2a、Ib-α-C和Ia-ε-PI-2a。未检测到耐青霉素菌株，分别有74.1%、64.2%和68.9%的菌株对红霉素、克林霉素和四环素耐药。中国感染性GBS分离株呈现出流行特征。
