Genetic Characterization of the O-Antigen and Development of a Molecular Serotyping Scheme for Enterobacter cloacae
Genetic Characterization of the O-Antigen and Development of a Molecular Serotyping Scheme for Enterobacter cloacae
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DOI：
10.3389/fmicb.2020.00727
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发表时间：
2020-04-28
影响因子：
5.2
通讯作者：
Guo, Xi
中科院分区：
文献类型：
--
作者：
Li, Yayue;Huang, Junjie;Guo, Xi
阴沟肠杆菌是一种与各种医院感染密切相关的条件致病菌。O-抗原是细胞表面变化最大的成分之一，传统上被广泛用于许多革兰氏阴性菌的血清学分类。阴沟肠杆菌根据O-抗原多样性分为30个血清型。本研究采用基因组学和比较基因组学方法，对26个阴沟肠杆菌血清型的O-抗原基因簇进行了深入分析。我们还鉴定了每种血清型的血清特异性基因，并建立了多重聚合酶链式反应(PCR)方法。该方法对基因组DNA的灵敏度为0.1 ng，对纯培养的克隆形成单位为10(3)个单位。对81株临床分离株进行双盲试验，评价方法的可靠性。此外，我们建立了一个有效的、基于基因组的工具，用于阴沟肠杆菌的电子血清学分型。通过对GenBank收录的431个阴沟肠杆菌基因组进行筛选，其中304个属于现行的抗原性方案，112个属于55个可能的新血清型。我们的结果首次揭示了阴沟肠杆菌O抗原多样性和变异的遗传基础，为研究该细菌的O抗原相关进化和致病机理提供了理论基础。此外，我们扩展了现有的阴沟肠杆菌的血清分型系统，这对于这种重要病原体的检测和流行病学监测目的是重要的。
Enterobacter cloacae is a well-characterized opportunistic pathogen that is closely associated with various nosocomial infections. The O-antigen, which is one of the most variable constituents on the cell surface, has been used widely and traditionally for serological classification of many gram-negative bacteria. E. cloacae is divided into 30 serotypes, based on its O-antigen diversity. In this study, by using genomic and comparative-genomic approaches, we analyzed the O-antigen gene clusters of 26 E. cloacae serotypes in depth. We also identified the sero-specific gene for each serotype and developed a multiplex polymerase chain reaction (PCR) method. The sensitivity of the assay was 0.1 ng for genomic DNA and 10(3) colony forming units for pure cultures. The assay reliability was evaluated by double-blinded testing with 81 clinical strains. Furthermore, we established a valid, genome-based tool for in silico serotyping of E. cloacae. By screening 431 E. cloacae genomes deposited in GenBank, 304 were classified into current antigenic scheme, and 112 were allocated into 55 putative novel serotypes. Our results represent the first genetic basis of the O-antigen diversity and variation of E. cloacae, providing a rationale for studying the O-antigen associated evolution and pathogenesis of this bacterium. In addition, we extended the current serotyping system for E. cloacae, which is important for detection and epidemiological surveillance purposes for this important pathogen.