Analysis of the Extracellular Proteome of Colistin-Resistant Korean Acinetobacter baumannii Strains

We
analyzed the extracellular proteome of colistin-resistant Korean Acinetobacter baumannii (KAB) strains to identify
proteome profiles that can be used to characterize extensively drug-resistant
KAB strains. Four colistin-resistant KAB strains with colistin resistance
associated with point mutations in pmrB and pmrC genes were analyzed. Analysis of the extracellular
proteome of these strains revealed the presence of 506 induced common
proteins, which were hence considered as the core extracellular proteome.
Class C ADC-30 and class D OXA-23 β-lactamases were abundantly
induced in these strains. Porins (CarO and CarO-like porin), outer
membrane proteins (OmpH and BamABDE), transport protein (AdeK), receptor
(TonB), and several proteins of unknown function were among the specifically
induced proteins. Based on the sequence homology analysis of proteins
from the core proteome and those of other A. baumannii strains and pathogenic bacterial species as well as further in silico
screening, we propose that CarO-like porin is an A.
baumannii-specific protein and that two tryptic peptides
that originate from CarO-like porin detected by tandem mass spectrometry
are peptide makers of this protein.