Lineage ST-17 complex group B strep. are more virulent t

系统发育谱系研究表明，与人类疾病相关的血清III型GBS主要来自两个不同的谱系。我们比较了侵袭性III型B组链球菌和定植菌株的系统发生谱系，以确定与侵袭性疾病相关的谱系。在一项前瞻性的多中心研究中，收集了29名早发性疾病婴儿和196名定植婴儿的分离株，通过多位点序列分型将其分配为序列类型(ST)。总体而言，54.5%的分离物在ST-19复合体中，40.4%在ST-17复合体中。与定植菌株相比，侵袭性菌株更有可能出现在ST-17复合体中(59%比38%，P=0.03)。在调整了潜在的混杂因素后，ST-17复合体比其他谱系更有可能与早发性疾病相关[优势比=2.51，95%可信区间1.02-6.20]。这些数据支持ST-17复合型GBS比其他III型GBS毒力更强的假设。

Phylogenetic lineage studies have demonstrated that serotype III GBS associated with human disease derive largely from two distinct lineages. We compared the phylogenetic lineages of invasive type III group B streptococci to those of colonizing strains in order to determine lineages associated with invasive disease. Isolates from 29 infants with early-onset disease and from 196 colonized infants, collected in a prospective, multicenter study, were assigned a sequence type (ST) by multi-locus sequence typing. Overall, 54.5% of the isolates were in the ST-19 complex and 40.4% were in the ST-17 complex. Invasive strains were more likely to be in the ST-17 complex compared to colonizing strains (59% vs. 38%, P=0.03). After adjusting for potential confounders, the ST-17-complex was more likely to be associated with early-onset disease than were other lineages [odds ratio = 2.51, 95% confidence interval 1.02 - 6.20]. These data support the hypothesis that ST-17 complex GBS are more virulent than other serotype III GBS.