Protein expression profiles in methicillin-resistant Staphylococcus aureus (MRSA) under effects of subminimal...

Area of Science:

• Microbiology
• Antibiotic Resistance
• Proteomics

Background:

• Imipenem, a beta-lactam antibiotic, primarily targets gram-negative bacteria but also affects methicillin-resistant Staphylococcus aureus (MRSA).
• The precise antibacterial mechanisms of imipenem against MRSA and in mixed infections remain incompletely understood.

Purpose of the Study:

• To identify proteins differentially expressed in MRSA following sub-inhibitory imipenem treatment.
• To elucidate the impact of imipenem on MRSA cellular processes and morphology.

Main Methods:

• Proteomic analysis using isobaric tag for relative and absolute quantitation (iTRAQ) to identify differentially expressed proteins (DEPs).
• Validation through multiple reaction monitoring (MRM) and quantitative PCR (qPCR).
• Morphological analysis using transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

Main Results:

• Identified 240 and 58 DEPs in standard (S3) and clinical (S23) MRSA strains, respectively, after sub-MIC imipenem exposure.
• Significant changes in DEPs related to cellular proliferation, metabolism, and virulence were observed.
• TEM and SEM revealed cell wall deficiency, lysis, and abnormal mitosis in the S23 strain.

Conclusions:

• Sub-MIC imipenem significantly impacts MRSA proteomes, affecting key cellular functions.
• Imipenem induces morphological damage in MRSA, including cell wall defects and lysis.
• Findings enhance understanding of imipenem's action against MRSA, informing treatment strategies for co-infections.