Proteomic Study of the Adaptive Mechanism of Ciprofloxacin-Resistant Staphylococcus aureus to the Host Environment.

Antibiotic-resistant bacteria can escape host immune killing and settle in the host to form persistent infections. In this study we investigated the adaptive mechanism of resistant Staphylococcus aureus to the host environment by data-independent acquisition-based quantitative proteomics and functional validation. The growth curve and minimum inhibitory concentration (MIC) indicated that ciprofloxacin-resistant (Cip-R) S. aureus showed a survival advantage over sensitive strains. Cip-R also exhibited a stronger invasion and biofilm formation ability than sensitive bacteria. Cip-R stimulation resulted in the improved production of inflammatory factors of the host cells. Proteomics study combined with biochemical validations showed that Cip-R obtained adaptability to the host via upregulation of the tricarboxylic acid cycle (TCA cycle) and downregulation of ribosome metabolism and protein folding to maintain energy to support Cip-R's survival. Thus, this study will help us to further explain the growth strategy of resistant bacteria to adapt to the host environment, and provide important information for the development of new antibacterial drugs.