Proteomic analysis of a carbapenem-resistant Klebsiella pneumoniae strain in response to meropenem stress

Abstract

Objectives: Antibiotic resistance has become a major problem in treating bacterial infections. The aim of this study was to elucidate the effects of meropenem on a bla_KPC-2-harbouring multidrug-resistant clinical strain of Klebsiella pneumoniae through a proteomics approach in order to attain a deeper understanding of bacterial resistance strategies.

Methods: Analysis was performed by two-dimensional gel electrophoresis of whole-cell extracts of bacteria exposed to a sublethal concentration of meropenem compared with the untreated control. Differentially expressed proteins were identified by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF).

Results: Based on Quantity One^® software and MALDI-TOF analysis, 16 overexpressed proteins were identified in meropenem-treated bacteria. These proteins were primarily enzymes involved in defence against oxidative stress as well as glycolytic enzymes. LysM domain/BON superfamily protein was found overexpressed by >12-fold. STRING-10 was used to determine protein-protein interaction among the overexpressed proteins and to predict their functional associations. This study demonstrated that treatment with meropenem resulted in upregulation of various proteins involved in defence and repair mechanisms along with enzymes of energy metabolism.

Conclusions: These overexpressed proteins may play an important role in bacterial resistance mechanisms against carbapenems, however their role in resistance needs to be further validated. High expression of lysine M domain/BON superfamily protein may indicate its possible involvement in modulating the bacterial response to antibiotic stress, but its actual role requires more investigation. These findings may also help in the development of newer therapeutic agents or diagnostic markers against carbapenem resistance.

Keywords: Antibiotic resistance; KPC-2; Klebsiella pneumonia; Proteomics.