Comparison of the outer membrane proteomes between clinical carbapenem-resistant and -susceptible Acinetobacter
1Department of Medical Microbiology and Immunology, Wannan Medical College, Wuhu, PR China.
Background And Aim:
Carbapenem resistance has become a major obstacle in combating Acinetobacter baumannii infections. Although enzymatic degradation by β-lactamases is the pivotal mechanism of carbapenem resistance, porin deficiency has also been implicated in the mechanism. In this study, outer membrane proteins (OMPs) pattern of a clinical multidrug-resistant A. baumannii isolate were analysed in order to attain a deeper understanding of carbapenem-resistance strategies.
Methods:
OMPs extracts, respectively, separated from carbapenem-resistant and -susceptible clinical A. baumannii isolates were compared using two-dimensional polyacrylamide gel electrophoresis. Differentially expressed proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF).
Results:
Twenty-three differently expressed proteins were identified between the resistant and susceptible isolates. Among them, six were annotated convincingly as OMPs in UniProt database. CarO was found absent from the resistant isolate and the expression levels of Omp33-36 and Omp25 were significantly lower than that in the susceptible counterpart. Strikingly, a LysM domain/BON superfamily protein, which has been linked to carbapenem resistance in Klebsiella pneumoniae, was found underexpressed by tenfold in the resistant isolate.
Conclusion:
Our study verified some porins which have been proven to play an important role in bacterial resistance against carbapenems. Underexpression of the LysM domain/BON superfamily protein may indicate its possible engagement in bacterial drug resistance, but its actual role requires more investigation.
Insights
Outer membrane protein (OMP) analysis revealed key differences in carbapenem-resistant Acinetobacter baumannii. Absence and reduced expression of specific porins, including CarO, contribute to carbapenem resistance strategies.
Area of Science:
- Microbiology
- Molecular Biology
- Drug Resistance
Background:
- Carbapenem resistance in Acinetobacter baumannii poses a significant clinical challenge.
- While beta-lactamases are primary resistance mechanisms, porin deficiency also contributes.
- Understanding outer membrane protein (OMP) alterations is crucial for deciphering resistance strategies.
Purpose of the Study:
- To analyze the outer membrane protein (OMP) profile of a multidrug-resistant Acinetobacter baumannii isolate.
- To identify OMPs involved in carbapenem resistance mechanisms.
- To gain deeper insights into bacterial strategies for overcoming carbapenem antibiotics.
Main Methods:
- Comparison of OMP extracts from carbapenem-resistant and susceptible Acinetobacter baumannii isolates.
- Utilized two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) for protein separation.
- Identified differentially expressed proteins using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.
Main Results:
- Identified 23 differentially expressed proteins between resistant and susceptible isolates.
- CarO porin was absent in the resistant isolate.
- Reduced expression of Omp33-36 and Omp25, and a tenfold underexpression of a LysM domain/BON superfamily protein were observed in the resistant isolate.
Conclusions:
- Confirmed the role of specific porins in bacterial carbapenem resistance.
- The underexpression of the LysM domain/BON superfamily protein suggests a potential role in drug resistance, warranting further investigation.
- Findings contribute to understanding carbapenem resistance mechanisms in Acinetobacter baumannii.
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