Proteomic Analyses Uncover the Mechanisms Underlying Antibiotic Resistance Differences among Three <b><i>Acinetobacter baumannii</i></b> Isolates

Abstract

This study aimed to investigate the molecular mechanisms underlying the antibiotic resistance difference among three Acinetobacter baumannii isolates. Fifty A. baumannii isolates were first subjected to an antimicrobial susceptibility test, then three isolates differing in antibiotic resistance were selected and subjected to iTRAQ (isobaric tags for relative and absolute quantification)-based proteomics analysis. Differential proteins among the three A. baumannii isolates were further identified and subjected to gene ontology functional enrichment analysis. A resistant isolate (A1), a less resistant one (A8) and a susceptible one (A9) were selected. In total, there were 424 differentially expressed proteins (DEPs) between the A1 and A8 isolates, 1,992 DEPs between the A9 and A1 isolates, and 1,956 DEPs between the A8 and A9 isolates. The upregulation of I6TUC8 and Q0GA83 in the A1 and A8 isolates may be responsible for their higher resistance to ceftriaxone. The higher gentamicin resistance of A. baumannii isolates A1 and A8 when compared to A9 may be related to the higher expression levels of O05286 and D0CCK1, while the higher Q2FCY1 expression level may contribute more to strong gentamicin resistance in A1. The higher levels of L9LWL7, L9MDB0, K9C9W3, E2IGU7, B6E129, G8HYR7, D2XTB0 and D2XTB0 may be responsible for the higher carbapenem resistance of isolate A1 as compared to A8.

iTRAQ-Based Quantitative Proteomic Analysis of Acinetobacter baumannii under Hypoxia and Normoxia Reveals the Role of OmpW as a Virulence Factor

“…Techniques that use the relative quantification of the proteome, such as the isobaric tags for relative and absolute quantitation (iTRAQ) approach, have been used for characterization of bacterial proteomes, providing important information regarding virulence factors ( 7 , 14 – 17 ). A. baumannii proteome analyses have also given new insights into the molecular mechanisms underlying its antibiotic resistance ( 18 , 19 ), the growth-phase-dependent changes observed in its proteome ( 20 ), the molecular mechanisms involved in the response to desiccation and persistence ( 21 ), and proteins involved in biofilm formation ( 22 ). However, no study has investigated the influence of hypoxia on the A. baumannii proteome during infection.…”