Increased Capsule Thickness and Hypermotility Are Traits of Carbapenem-Resistant Acinetobacter baumannii ST3 Strains Causing Fulminant Infection
OPEN FORUM INFECTIOUS DISEASES(2021)
摘要
Background. Acinetobacter baumannii is a successful nosocomial pathogen, causing severe, life-threatening infections in hospitalized patients, including pneumonia and bloodstream infections. The spread of carbapenem-resistant Acinetobacter baumannii (CRAB) strains is a major health threat worldwide. The successful spread of CRAB is mostly due to its highly plastic genome. Although some virulence factors associated with CRAB have been uncovered, many mechanisms contributing to its success are not fully understood. Methods. Here we describe strains of CRAB that were isolated from fulminant cases in 2 hospitals in Israel. These isolates show a rare hypermucoid (HM) phenotype and were investigated using phenotypic assays, comparative genomics, and an in vivo Galleria mellonella model. Results. The 3 isolates belonged to the ST3 international clonal type and were closely related to each other, as shown by Fourier-transform infrared spectroscopy and phylogenetic analyses. These isolates possessed thickened capsules and a dense filamentous extracellular polysaccharides matrix as shown by transmission electron microscopy (TEM), and overexpressed the capsule polysaccharide synthesis pathway-related wzc gene. Conclusions. The HM isolates possessed a unique combination of virulence genes involved in iron metabolism, protein secretion, adherence, and membrane glycosylation. HM strains were more virulent than control strains in 2 G. mellonella infection models. In conclusion, our findings demonstrated several virulence factors, all present in 3 CRAB isolates with rare hypermucoid phenotypes.
更多查看译文
关键词
carbapenem-resistant Acinetobacter baumannii,capsule,K-locus,mucoid phenotype,virulence
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要