iTRAQ-based proteome analysis of fluoroquinolone-resistant Staphylococcus aureus.

Area of Science:

• Microbiology
• Proteomics
• Molecular Biology

Background:

• Staphylococcus aureus is a significant pathogen.
• Multidrug resistance (MDR) in S. aureus is a growing concern.
• Fluoroquinolones (FQs) are important antibiotics used to treat S. aureus infections.

Purpose of the Study:

• To compare global protein expression changes in Staphylococcus aureus during fluoroquinolone (FQ) exposure.
• To identify proteins associated with the development of FQ resistance.
• To investigate the role of SOS and stress response proteins in FQ resistance.

Main Methods:

• Proteomic analysis using 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) and LC-MS/MS.
• Bioinformatic analysis including Gene Ontology (GO) annotation and protein-protein interaction network construction (STRING).
• Validation of recA gene expression using real-time quantitative reverse transcription PCR (qRT-PCR).

Main Results:

• 147 unique proteins showed significant expression changes in FQ-exposed S. aureus compared to wild-type.
• Altered protein expression was linked to SOS response (RecA), antibiotic resistance (MgrA), pathogenesis, and stress response pathways.
• Network analysis revealed protein clusters involved in metabolic pathways, aminoacyl-tRNA biosynthesis, and ribosome structure.

Conclusions:

• Development of FQ resistance in S. aureus is associated with altered expression of proteins involved in SOS and stress responses.
• Upregulation of SOS and stress response proteins is a key mechanism in the development of multidrug resistance.
• Proteomics provides valuable insights into the molecular mechanisms underlying antibiotic resistance in S. aureus.