Lim Shu Yong, Yap Kien-Pong, Teh Cindy Shuan Ju, Jabar Kartini Abdul, Thong Kwai Lin
Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Infect Genet Evol. 2017 Apr;49:55-65. doi: 10.1016/j.meegid.2016.12.029. Epub 2016 Dec 28.
Enterococcus faecium is both a commensal of the human intestinal tract and an opportunistic pathogen. The increasing incidence of enterococcal infections is mainly due to the ability of this organism to develop resistance to multiple antibiotics, including vancomycin. The aim of this study was to perform comparative genome analyses on four vancomycin-resistant Enterococcus faecium (VRE) strains isolated from two fatal cases in a tertiary hospital in Malaysia. Two sequence types, ST80 and ST203, were identified which belong to the clinically important clonal complex (CC) 17. This is the first report on the emergence of ST80 strains in Malaysia. Three of the studied strains (VREr5, VREr6, VREr7) were each isolated from different body sites of a single patient (patient Y) and had different PFGE patterns. While VREr6 and VREr7 were phenotypically and genotypically similar, the initial isolate, VREr5, was found to be more similar to VRE2 isolated from another patient (patient X), in terms of the genome contents, sequence types and phylogenomic relationship. Both the clinical records and genome sequence data suggested that patient Y was infected by multiple strains from different clones and the strain that infected patient Y could have derived from the same clone from patient X. These multidrug resistant strains harbored a number of virulence genes such as the epa locus and pilus-associated genes which could enhance their persistence. Apart from that, a homolog of E. faecalis bee locus was identified in VREr5 which might be involved in biofilm formation. Overall, our comparative genomic analyses had provided insight into the genetic relatedness, as well as the virulence potential, of the four clinical strains.
屎肠球菌既是人类肠道的共生菌，也是一种机会致病菌。肠球菌感染发病率的上升主要归因于该菌对包括万古霉素在内的多种抗生素产生耐药性的能力。本研究的目的是对从马来西亚一家三级医院的两例死亡病例中分离出的四株耐万古霉素屎肠球菌（VRE）进行比较基因组分析。鉴定出两种序列类型，即ST80和ST203，它们属于具有临床重要性的克隆复合体（CC）17。这是马来西亚首次报道ST80菌株的出现。三株被研究的菌株（VREr5、VREr6、VREr7）分别从一名患者（患者Y）的不同身体部位分离得到，且具有不同的脉冲场凝胶电泳（PFGE）图谱。虽然VREr6和VREr7在表型和基因型上相似，但最初分离出的菌株VREr5在基因组内容、序列类型和系统发育关系方面，被发现与从另一名患者（患者X）分离出的VRE2更为相似。临床记录和基因组序列数据均表明，患者Y感染了来自不同克隆的多种菌株，而感染患者Y的菌株可能源自与患者X相同的克隆。这些多重耐药菌株携带了许多毒力基因，如epa位点和菌毛相关基因，这些基因可增强它们的生存能力。除此之外，在VREr5中鉴定出了粪肠球菌bee位点的一个同源物，它可能参与生物膜的形成。总体而言，我们的比较基因组分析为这四株临床菌株的遗传相关性以及毒力潜力提供了深入见解。
