Bap-Independent Biofilm Formation in Staphylococcus xylosus.

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Pathogenesis

Background:

• Biofilm associated protein (Bap) is crucial for biofilm formation in Staphylococcus aureus V329.
• Bap orthologs are present in most Staphylococcus xylosus strains, but their role in biofilm formation remains unelucidated.

Purpose of the Study:

• To investigate the effect of Bap on biofilm formation in S. xylosus.
• To compare the motif structure of S. xylosus Bap with that of S. aureus Bap.

Main Methods:

• Comparative analysis of Bap structure between S. aureus V329 and two S. xylosus strains (TMW 2.1023, TMW 2.1523).
• Disruption of the bap gene in S. xylosus strains.
• Assessment of cell aggregation and biofilm formation under various conditions.
• Phenotypic analysis including Congo Red Agar (CRA) assays and calcium sensitivity tests.

Main Results:

• S. xylosus Bap exhibits differences in key factors like isoelectric point, protein homology, and repeat types compared to S. aureus Bap, despite similar overall structure.
• Disruption of the bap gene in S. xylosus had no significant effect on cell aggregation and minimal impact on biofilm formation.
• S. xylosus strains did not display typical S. aureus Bap-positive phenotypes, such as impaired function with calcium or rough colony morphology on CRA.

Conclusions:

• The function of S. aureus Bap cannot be directly extrapolated to S. xylosus Bap.
• Bap is non-essential for biofilm formation in the studied S. xylosus strains.
• Biofilm formation in S. xylosus likely involves different and multifactorial mechanisms independent of Bap.