Impact of individual extracellular proteases on Staphylococcus aureus biofilm formation in diverse clinical isolates and their isogenic sarA mutants.
Bottom Line: These results confirm an important role for multiple extracellular proteases in S. aureus pathogenesis and the importance of sarA in repressing their production.Moreover, purified aureolysin limited biofilm formation in 14 of 15 methicillin-resistant isolates and 11 of 15 methicillin-susceptible isolates, while dispersin B had little impact in UAMS-1, LAC, or 29 of 30 contemporary isolates of S. aureus.This suggests that the role of sarA and its impact on protease production is important in diverse strains of S. aureus irrespective of their methicillin resistance status.
Affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.Show MeSH
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Mentions: Finally, to further examine the impact of proteases on S. aureus biofilm formation, and specifically address the hypothesis that protein-mediated biofilm formation plays an important role in MRSA, while PIA plays the more important role in MSSA (O'Neill et al. 2008; Houston et al. 2011; Pozzi et al. 2012), we generated mutations in the genes encoding FnbA, Spa, or the enzymes necessary for PIA production (ica operon) in the methicillin-susceptible strain UAMS-1 and examined the impact on biofilm formation. The results of these experiments confirmed that protein-mediated biofilm formation plays an important role in this strain and provided a possible explanation for this hypothesis. Specifically, mutation of the ica operon had a greater impact in UAMS-1 than mutation of spa or fnbA. However, mutation of fnbA and spa limited biofilm formation in UAMS-1 to a significantly greater extent than mutation of ica (Fig. 8). These results confirm that protein-mediated biofilm formation is more important than PIA-mediated biofilm formation, even in the methicillin-susceptible strain UAMS-1.
Affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.