Global Comparison of the Membrane Subproteomes between a Multidrug-Resistant Acinetobacter baumannii Strain and a Reference Strain

Abstract

Acinetobacter baumannii causes severe infections in compromised patients. We combined SDS-PAGE, two-dimensional gel electrophoresis and mass spectrometry (LC-MS/MS and MALDI-TOF) to separate and characterize the proteins of the cell envelope of this bacterium. In total, 135 proteins (inner and outer membrane proteins) were identified. In this analysis, we described the expression by this bacterium of RND-type efflux systems and some potential virulence factors. We then compared the membrane subproteome of a clinical multidrug-resistant (MDR) isolate with that of a reference strain. We found that the MDR strain expressed lower levels of the penicillin-binding-protein 1b, produced a CarO protein having different primary and quaternary structures to that of the reference strain, and expressed OmpW isoforms. We also showed that the clinical strain has a high ability to form biofilms consistent with the accumulation of some outer membrane proteins (OMPs) such as NlpE or CsuD that have already been described as involved in bacterial adhesion. These features may partly explain the MDR emergence of the clinical isolate.

Identification of novel vaccine candidates againstAcinetobacter baumanniiusing reverse vaccinology

“…12 To enhance the power of reverse vaccinology, we also integrated functional genomics and proteomic analysis using bioinformatics tools to further refine the screening criteria for protective antigens. We (results to be published elsewhere) and others [17][18]25,28 used HPLC-MS/MS to analyze the proteomic profiles of OMVs and identified 65 potential antigens from A. baumannii ATCC17978 strains (Table S1). Meanwhile, we have also exploited proteomic information on outer membrane and/or secreted proteins predicted from 6 previous experimental in vivo studies.…”

“…Meanwhile, we have also exploited proteomic information on outer membrane and/or secreted proteins predicted from 6 previous experimental in vivo studies. 18,22,23,[25][26][27][28] Taking together the information collected for homologous core genes, in vitro published proteomic information, and in silico predicted secretome profiles, 77 A. baumannii proteins were identified and selected as the most promising vaccine candidates (Fig. 2 & Table S2).…”

“…analysis of OMVs secreted by bacteria, differential expression analysis of virulent strains, in vivo animal model challenge studies, and immuno-proteomics, it provides an important platform to identify novel protective antigens. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Furthermore, through these studies and analyses, we can also deeply understand the pathogenesis of Ab bacteria. In this study, we used an integrated approach combining reverse vaccinology, bioinformatics-based structural analysis and results obtained from published proteomics studies to screen and identify potential protective antigens against Ab infections.…”

Outer Membrane Vesicle Proteomics to Discover the Pathogenicity of Acinetobacter baumannii

“…This multipleapproach strategy showed a unique lifestyle of A. baumannii involved in biofilms formation [20]. Similarly, high-end isoelectric point proteome analysis of Acinetobacter radioresistens reveals that 'envelope stress responses' can be induced by aromatic compounds [21][22][23]. Using 2D-DIGE and mass analysis, Minami et al demonstrated that alteration in proteomic profiles of detergent-resistant membrane fractions during cold acclimation [24].…”

“…Yun et al, performed differential quantitative proteomic analysis of outer membrane from multidrug-resistant Acinetobacter baumannii and reported that carbapenem induces the expression of resistance-nodulation-cell division transporters, protein kinases and suppress outer membrane proteins expression [19]. Carbapenem resistance of Acinetobacter baumannii has been studied using outer membrane proteomics between wild type and carbapenem resistance strain of Acinetobacter baumannii [12,16,21,22].…”