Novel Determinants of Intestinal Colonization of Salmonella enterica Serotype Typhimurium Identified in Bovine Enteric Infection
Novel Determinants of Intestinal Colonization of Salmonella enterica Serotype Typhimurium Identified in Bovine Enteric Infection
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DOI：
10.1128/iai.00874-13
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发表时间：
2013-11-01
影响因子：
3.1
通讯作者：
Andrews-Polymenis, Helene
中科院分区：
文献类型：
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作者：
Elfenbein, Johanna R.;Endicott-Yazdani, Tiana;Andrews-Polymenis, Helene
牛自然感染鼠伤寒血清型肠道沙门氏菌，并表现出与人类极为相似的肠道沙门氏菌病病理特征。牛是具有完整微生物群的动物中由非伤寒沙门氏菌感染引起的胃肠道疾病的最相关模型。我们利用该模型筛选目标单基因缺失突变体库，以确定鼠伤寒沙门氏菌在肠道感染期间生存所需的新基因。精心挑选了 54 个候选突变体，其中包括已知对沙门氏菌胃肠道存活很重要的许多基因突变。在牛结扎回肠环中测试了先前未经证实的胃肠道感染表型的三个基因。其中两个突变体 STM3602 和 STM3846 重现了突变体库中观察到的表型。互补实验成功逆转了观察到的表型，将这些基因与相应突变株的定植缺陷直接联系起来。 STM3602 编码可能参与磷酸盐利用的推定转录调节因子，STM3846 编码逆转录子逆转录酶，该酶产生独特的 RNA-DNA 混合分子，称为多拷贝单链 DNA。本研究中鉴定的基因代表了一类令人兴奋的新毒力决定因素，可用于进一步的机制研究，以阐明沙门氏菌在牛小肠内生存所采用的策略。
Cattle are naturally infected with Salmonella enterica serotype Typhimurium and exhibit pathological features of enteric salmonellosis that closely resemble those in humans. Cattle are the most relevant model of gastrointestinal disease resulting from non-typhoidal Salmonella infection in an animal with an intact microbiota. We utilized this model to screen a library of targeted single-gene deletion mutants to identify novel genes of Salmonella Typhimurium required for survival during enteric infection. Fifty-four candidate mutants were strongly selected, including numerous mutations in genes known to be important for gastrointestinal survival of salmonellae. Three genes with previously unproven phenotypes in gastrointestinal infection were tested in bovine ligated ileal loops. Two of these mutants, STM3602 and STM3846, recapitulated the phenotype observed in the mutant pool. Complementation experiments successfully reversed the observed phenotypes, directly linking these genes to the colonization defects of the corresponding mutant strains. STM3602 encodes a putative transcriptional regulator that may be involved in phosphonate utilization, and STM3846 encodes a retron reverse transcriptase that produces a unique RNA-DNA hybrid molecule called multicopy single-stranded DNA. The genes identified in this study represent an exciting new class of virulence determinants for further mechanistic study to elucidate the strategies employed by Salmonella to survive within the small intestines of cattle.