Staphylococcus pseudintermedius biofilms secrete factors that induce inflammatory reactions in vitro

Area of Science:

• Veterinary microbiology
• Immunology
• Bacterial pathogenesis

Background:

• Bacterial biofilms, particularly from Staphylococcus pseudintermedius, are linked to chronic infections and inflammation.
• The direct role of S. pseudintermedius biofilms in regulating host inflammatory reactions remains unclear.

Purpose of the Study:

• To investigate the inflammatory effects of metabolites from S. pseudintermedius biofilms in vitro.
• To elucidate the mechanisms by which S. pseudintermedius biofilms modulate host immune responses.

Main Methods:

• Culturing S. pseudintermedius biofilms and collecting biofilm-conditioned medium (BCM).
• Assessing inflammatory marker expression (IL-1β, IL-6 mRNA) in RAW264.7 cells exposed to BCM.
• Analyzing heat resistance and Toll-like receptor (TLR) pathway activation of BCM components.
• Correlating biofilm formation capacity with inflammatory response intensity using SDS-PAGE.

Main Results:

• BCM significantly increased interleukin-1 beta and interleukin-6 mRNA expression in immune cells.
• Secreted proteins in BCM were heat-resistant and activated the TLR signaling pathway.
• Stronger biofilm producers induced greater inflammatory reactions and exhibited distinct protein profiles.

Conclusions:

• Proteins secreted by S. pseudintermedius biofilms induce host inflammatory responses through TLR signaling.
• The potency of biofilm production influences the severity of inflammation.
• Identified proteins may be key factors in biofilm-related inflammation, offering potential targets for novel therapeutics.