与不同临床综合征相关的B族链球菌毒力因子：孕妇无症状携带及新生儿早发型疾病

Group B streptococcus virulence factors associated with different clinical syndromes: Asymptomatic carriage in pregnant women and early-onset disease in the newborn.

作者信息

Schindler Yulia, Rahav Galia, Nissan Israel, Treygerman Orit, Prajgrod George, Attia Bracha Zukerman, Raz Ronit, Valenci Gal Zizelski, Tekes-Manova Dorit, Maor Yasmin

机构信息

Laboratory of Microbiology, Mayanei Hayeshua Medical Center, Bnei Brak, Israel.

Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.

出版信息

Front Microbiol. 2023 Feb 13;14:1093288. doi: 10.3389/fmicb.2023.1093288. eCollection 2023.

BACKGROUND

Group B streptococcus (GBS) harbors many virulence factors but there is limited data regarding their importance in colonization in pregnancy and early-onset disease (EOD) in the newborn. We hypothesized that colonization and EOD are associated with different distribution and expression of virulence factors.

METHODS

We studied 36 GBS EOD and 234 GBS isolates collected during routine screening. Virulence genes (pilus-like structures-; and ) presence and expression were identified by PCR and qRT-PCR. Whole genome sequencing (WGS) and comparative genomic analyses were used to compare coding sequences (CDSs) of colonizing and EOD isolates.

RESULTS

Serotype III (ST17) was significantly associated with EOD and serotype VI (ST1) with colonization. and genes were more prevalent among EOD isolates (58.3 and 77.8%, respectively; < 0.01). The pilus loci and were more prevalent among EOD isolates (61.1%, < 0.01), while the pilus loci and among colonizing isolates (89.7 and 93.1% vs. 55.6 and 69.4%, < 0.01). qRT PCR analysis revealed that was barely expressed in colonizing isolates, even though the gene was detected. Expression of the gene and was two-fold higher in EOD isolates compared to colonizing isolates. Transcription of was three-fold higher in colonizing isolates compared to EOD isolates. ST17 isolates (associated with EOD) had a smaller genome size compared ST1 and the genome was more conserved relative to the reference strain and ST17 isolates. In a multivariate logistic regression analysis virulence factors independently associated with EOD were serotype 3, and and was protective.

CONCLUSION

There was a significant difference in the distribution of , , and genes among EOD (serotype III/ST17) and colonizing (serotype VI/ST1) isolates suggesting an association between invasive disease and these virulence factors. Further study is needed to understand the contribution of these genes to GBS virulence.

背景

B族链球菌（GBS）具有多种毒力因子，但关于它们在孕期定植及新生儿早发型疾病（EOD）中的重要性的数据有限。我们推测定植和EOD与毒力因子的不同分布及表达有关。

方法

我们研究了在常规筛查期间收集的36株GBS EOD菌株和234株GBS分离株。通过PCR和qRT-PCR鉴定毒力基因（菌毛样结构基因；和）的存在及表达。使用全基因组测序（WGS）和比较基因组分析来比较定植菌株和EOD菌株的编码序列（CDS）。

结果

血清型III（ST17）与EOD显著相关，血清型VI（ST1）与定植相关。和基因在EOD分离株中更为普遍（分别为58.3%和77.8%； < 0.01）。菌毛位点和在EOD分离株中更为普遍（61.1%， < 0.01），而定植分离株中的菌毛位点和更为普遍（89.7%和93.1%，相比之下EOD分离株为55.6%和69.4%， < 0.01）。qRT-PCR分析显示，即使检测到该基因，在定植分离株中也几乎不表达。与定植分离株相比，基因和的表达在EOD分离株中高两倍。与EOD分离株相比，的转录在定植分离株中高两倍。与ST1相比，与EOD相关的ST17分离株基因组较小，并且相对于参考菌株和ST17分离株，基因组更为保守。在多变量逻辑回归分析中，与EOD独立相关的毒力因子是血清型3，和具有保护作用。