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: To determine the extent to which this is true in other strains, we evaluated the impact of purified aureolysin on biofilm formation in each of 30 contemporary clinical isolates obtained from different, unrelated patients sourced over a 15-year period at Arkansas Children's Hospital, with these 30 strains being split evenly between MRSA and MSSA. We found that purified aureolysin limited biofilm formation to a statistically significant degree in 14 of 15 MRSA strains and 11 of 15 MSSA strains, with almost all of the exceptions in both cases being strains that did not produce a robust biofilm under the in vitro conditions we employed in our experiments (Fig. 9). In contrast, dispersin B (Kane Biotech), a soluble glycoside hydrolase produced by Actinobacillus actinomycetemcomitans that inhibits PIA-mediated biofilm formation (Donelli et al. 2007; Sugimoto et al. 2013), limited biofilm formation in the S. epidermidis strain RP62A, but had no impact in UAMS-1, LAC (Fig. 10), or 29 of 30 of these clinical isolates (Fig. 11). Of note is the fact that only one strain was significantly altered by addition of dispersin B but that the change was a significant increase rather than decrease in biofilm formation. Taken together we can show that dispersin B is effective against PIA-mediated biofilm formation, and that methicillin resistance does not play a significant role in determining biofilm structure in clinical isolates.
Affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.