ClpB regulates biofilm formation in Methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) biofilms play a significant role in chronic infections and treatment resistance. While the chaperone protein ClpB is known for its involvement in bacterial stress responses, its specific function in regulating MRSA biofilms and toxicity remains unclear. To address this gap, we generated clpB knockout strain (ΔclpB) and clpB complementation strain (CΔclpB) in MRSA USA300 and conducted a comprehensive analysis comparing its biofilm characteristics to the wild type (WT) strain. Our assessment included crystal violet staining, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and quantification of extracellular matrix components (eDNA, polysaccharides, proteins). Furthermore, we employed a mouse skin infection model to evaluate wound healing, histopathological changes (H&E staining), and the host inflammatory response (TNF-α/IL-6 ELISA and RT-PCR). Our results demonstrate that the ΔclpB strain exhibited a significantly reduced biofilm biomass (p < 0.0001) and displayed structural deficiencies with decreased extracellular matrix content. However, the CΔclpB strain showed similar results to the wild type of strain. In vivo experiments revealed that mice infected with ΔclpB exhibited accelerated wound closure, mitigated tissue damage, and reduced levels of TNF-α and IL-6 at protein and transcriptional levels compared to those infected with the WT strain. These findings underscore the crucial role of ClpB in regulating MRSA biofilm formation and virulence, potentially through modulation of extracellular matrix composition and host inflammatory responses. Consequently, targeting ClpB could offer a promising avenue for developing novel anti-biofilm strategies against MRSA infections.