PDF(Pubmed)
Abstract：
GBS may cause a devastating disease in newborns. In early onset disease of the newborn the bacteria are acquired from the colonized mother during delivery. We characterized type VII secretion system (T7SS), exporting small proteins of the WXG100 superfamily, in group B Streptococci (GBS) isolates from pregnant colonized women and newborns with early onset disease (EOD) to better understand T7SS contribution to virulence in these different clinical scenarios.
GBS genomes [N=33, 17 EOD isolates (serotype III/ST17) and 16 colonizing isolates (12 serotype VI/ST1, one serotype VI/ST19, one serotype VI/ST6, and two serotype 3/ST19)] were analyzed for presence of T7SS genes and genes encoding WXG100 proteins. We also perform bioinformatic analysis. Galleria mellonella larvae were used to compare virulence between colonizing, EOD, and mutant EOD isolates. The EOD isolate number 118659 (III/ST17) was used for knocking out the essC gene encoding a membrane-bound ATPase, considered the driver of T7SS.
Most GBS T7SS loci encoded core component genes: essC, membrane-embedded proteins (essA; essB), modulators of T7SS activity (esaA; esaB; esaC) and effectors: [esxA (SAG1039); esxB (SAG1030)].Bioinformatic analysis indicated that based on sequence type (ST) the clinicalGBS isolates encode at least three distinct subtypes of T7SS machinery. In all ST1isolates we identified two copies of esxA gene (encoding putative WXG100proteins), when only 23.5% of the ST17 isolates harbored the esxA gene. Five ST17isolates encoded two copies of the essC gene. Orphaned WXG100 molecule(SAG0230), distinct from T7SS locus, were found in all tested strains, except inST17 strains where the locus was found in only 23.5% of the isolates. In ST6 andST19 isolates most of the structure T7SS genes were missing. EOD isolates demonstrated enhanced virulence in G. mellonella modelcompared to colonizing isolates. The 118659DessC strain was attenuated in itskilling ability, and the larvae were more effective in eradicating 118659DessC.
We demonstrated that T7SS plays a role during infection. Knocking out the essC gene, considered the driver of T7SS, decreased the virulence of ST17 responsible for EOD, causing them to be less virulent comparable to the virulence observed in colonizing isolates.
GBS genomes [N=33, 17 EOD isolates (serotype III/ST17) and 16 colonizing isolates (12 serotype VI/ST1, one serotype VI/ST19, one serotype VI/ST6, and two serotype 3/ST19)] were analyzed for presence of T7SS genes and genes encoding WXG100 proteins. We also perform bioinformatic analysis. Galleria mellonella larvae were used to compare virulence between colonizing, EOD, and mutant EOD isolates. The EOD isolate number 118659 (III/ST17) was used for knocking out the essC gene encoding a membrane-bound ATPase, considered the driver of T7SS.
Most GBS T7SS loci encoded core component genes: essC, membrane-embedded proteins (essA; essB), modulators of T7SS activity (esaA; esaB; esaC) and effectors: [esxA (SAG1039); esxB (SAG1030)].Bioinformatic analysis indicated that based on sequence type (ST) the clinicalGBS isolates encode at least three distinct subtypes of T7SS machinery. In all ST1isolates we identified two copies of esxA gene (encoding putative WXG100proteins), when only 23.5% of the ST17 isolates harbored the esxA gene. Five ST17isolates encoded two copies of the essC gene. Orphaned WXG100 molecule(SAG0230), distinct from T7SS locus, were found in all tested strains, except inST17 strains where the locus was found in only 23.5% of the isolates. In ST6 andST19 isolates most of the structure T7SS genes were missing. EOD isolates demonstrated enhanced virulence in G. mellonella modelcompared to colonizing isolates. The 118659DessC strain was attenuated in itskilling ability, and the larvae were more effective in eradicating 118659DessC.
We demonstrated that T7SS plays a role during infection. Knocking out the essC gene, considered the driver of T7SS, decreased the virulence of ST17 responsible for EOD, causing them to be less virulent comparable to the virulence observed in colonizing isolates.
摘要：
GBS可能在新生儿中引起毁灭性疾病。在新生儿的早发性疾病中，细菌是在分娩过程中从定植的母亲获得的。我们表征了VII型分泌系统（T7SS），输出WXG100超家族的小蛋白，在B组中，从妊娠定植妇女和早发性疾病（EOD）新生儿中分离出链球菌（GBS），以更好地了解T7SS在这些不同临床情景中对毒力的贡献。
分析GBS基因组[N=33,17个EOD分离株(血清型III/ST17)和16个定殖分离株(12个血清型VI/ST1,一个血清型VI/ST19,一个血清型VI/ST6,和两个血清型3/ST19)]中T7SS基因和编码WXG100蛋白的基因的存在。我们还进行生物信息学分析。巨形球菌幼虫用于比较定殖之间的毒力，EOD,和突变的EOD分离株。EOD分离号118659（III/ST17）用于敲除编码膜结合ATP酶的essC基因，考虑到T7SS的驱动程序。
大多数GBST7SS基因座编码的核心成分基因：essC，膜包埋蛋白（essA；essB），T7SS活动的调节剂(esaA;esaB;esaC)和效应子:[esxA(SAG1039);esxB(SAG1030)]。生物信息学分析表明，基于序列类型（ST），临床GBS分离株编码至少三种不同的T7SS机制亚型。在所有ST1分离物中，我们鉴定了两个拷贝的esxA基因（编码推定的WXG100蛋白），只有23.5%的ST17分离株携带esxA基因。五个ST17分离株编码两个拷贝的essC基因。孤立WXG100分子(SAG0230),与T7SS基因座不同，在所有测试菌株中发现，除了在ST17菌株中，仅在23.5％的分离株中发现了基因座。在ST6和ST19分离株中，大多数结构T7SS基因缺失。与定殖分离株相比，EOD分离株在G.melonella模型中表现出增强的毒力。118659DessC菌株的技能能力减弱，幼虫更有效地根除118659DessC。
我们证明了T7SS在感染过程中起作用。敲出essC基因，考虑到T7SS的驱动程序，降低了负责EOD的ST17的毒力，导致它们的毒性低于定殖分离株中观察到的毒性。
分析GBS基因组[N=33,17个EOD分离株(血清型III/ST17)和16个定殖分离株(12个血清型VI/ST1,一个血清型VI/ST19,一个血清型VI/ST6,和两个血清型3/ST19)]中T7SS基因和编码WXG100蛋白的基因的存在。我们还进行生物信息学分析。巨形球菌幼虫用于比较定殖之间的毒力，EOD,和突变的EOD分离株。EOD分离号118659（III/ST17）用于敲除编码膜结合ATP酶的essC基因，考虑到T7SS的驱动程序。
大多数GBST7SS基因座编码的核心成分基因：essC，膜包埋蛋白（essA；essB），T7SS活动的调节剂(esaA;esaB;esaC)和效应子:[esxA(SAG1039);esxB(SAG1030)]。生物信息学分析表明，基于序列类型（ST），临床GBS分离株编码至少三种不同的T7SS机制亚型。在所有ST1分离物中，我们鉴定了两个拷贝的esxA基因（编码推定的WXG100蛋白），只有23.5%的ST17分离株携带esxA基因。五个ST17分离株编码两个拷贝的essC基因。孤立WXG100分子(SAG0230),与T7SS基因座不同，在所有测试菌株中发现，除了在ST17菌株中，仅在23.5％的分离株中发现了基因座。在ST6和ST19分离株中，大多数结构T7SS基因缺失。与定殖分离株相比，EOD分离株在G.melonella模型中表现出增强的毒力。118659DessC菌株的技能能力减弱，幼虫更有效地根除118659DessC。
我们证明了T7SS在感染过程中起作用。敲出essC基因，考虑到T7SS的驱动程序，降低了负责EOD的ST17的毒力，导致它们的毒性低于定殖分离株中观察到的毒性。
