Outer membrane vesicles isolated from two clinical Acinetobacter baumannii strains exhibit different toxicity and proteome characteristics

Microb Pathog. 2015 Apr:81:46-52. doi: 10.1016/j.micpath.2015.03.009. Epub 2015 Mar 12.

Abstract

Outer membrane vesicles (OMVs) are well-characterized virulence factors produced by Gram-negative bacteria. Here, we isolated two clinical Acinetobacter baumannii strains, the multidrug-resistant A. baumannii (MDRAb) A38 and non-MDRAb 5806. Strain A38 produced more abundant OMVs than strain 5806 when cultured to the early stationary phase. The results from cell proliferation assays and real-time PCR analyses indicated that A38 OMVs induced more powerful cytotoxicity and stronger innate immune responses compared with 5806 OMVs. Moreover, SDS-PAGE and LC-MS/MS analyses revealed that A38 OMVs contained more virulence factors, including Omp38, EpsA, Ptk, GroEL, hemagglutinin-like protein, and FilF. Taken together, the results of the present study suggest that MDRAb might produce abundant OMVs with more virulent factors facilitating the worse outcome, a finding that merits further study.

Keywords: Acinetobacter baumannii; Innate immunity; Outer membrane vesicles; Proteomics; Virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / microbiology
  • Acinetobacter baumannii / isolation & purification
  • Acinetobacter baumannii / metabolism*
  • Animals
  • Bacterial Proteins / analysis
  • Cell Death*
  • Cell Line
  • Chromatography, Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Epithelial Cells / metabolism
  • Epithelial Cells / physiology
  • Humans
  • Macrophages / metabolism
  • Macrophages / physiology
  • Mice
  • Proteome / analysis*
  • Secretory Vesicles / chemistry*
  • Secretory Vesicles / metabolism*
  • Tandem Mass Spectrometry
  • Virulence Factors / analysis*

Substances

  • Bacterial Proteins
  • Proteome
  • Virulence Factors