Characterization of Staphylococcus aureus biofilms via crystal violet binding and biochemical composition assays of isolates from hospitals, raw meat, and biofilm-associated gene mutants.

Autor: Ball AL; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Augenstein ED; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Wienclaw TM; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Richmond BC; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Freestone CA; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Lewis JM; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Thompson JS; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Pickett BE; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA., Berges BK; Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA. Electronic address: brad.berges@gmail.com.
Jazyk: angličtina
Zdroj: Microbial pathogenesis [Microb Pathog] 2022 Jun; Vol. 167, pp. 105554. Date of Electronic Publication: 2022 May 05.
DOI: 10.1016/j.micpath.2022.105554
Abstrakt: Staphylococcus aureus (SA) is a gram-positive coccus and an opportunistic pathogen of humans. The ability of SA to form biofilms is an important virulence mechanism because biofilms are protected from host immune responses and antibiotic treatment. This study examines the relative biofilm strength of a variety of hospital and meat-associated strains of SA, using a crystal violet (CV) staining assay. Biofilms were treated with either DNase or proteinase K prior to CV staining, and compared to mock-treated results, to better understand the biochemical composition. Biofilm polysaccharide concentration was also measured using the phenol sulfuric-acid assay which was normalized to base biofilm strength. We found that hospital-associated isolates have biofilms that bind significantly more CV than for meat isolates and are significantly more protein and polysaccharide-based while meat isolates have significantly more DNA-based biofilms. This study also investigates the effects that biofilm-related genes have on biofilm formation and composition by analyzing specific transposon mutants of genes previously shown to play a role in biofilm development. agrA, atl, clfA, fnbA, purH, and sarA mutants produce significantly weaker biofilms (bind less CV) as compared to a wild-type control, whereas the acnA mutant produces a significantly stronger biofilm. Biofilms formed from these mutant strains were treated (or mock-treated) with DNase or proteinase K and tested with phenol and sulfuric acid to determine what role these genes play in biofilm composition. The acnA, clfA, fnbA, and purH mutants showed significant reduction in biofilm staining after either proteinase K or DNase treatment, agrA and sarA mutants showed significant biofilm reduction after only proteinase K treatment, and an atl mutant did not show significant biofilm reduction after either proteinase K or DNase treatment. These data suggest that biofilms that form without acnA, clfA, fnbA, and purH are DNA- and protein-based, that biofilms lacking agrA and sarA are mainly protein-based, and biofilms lacking atl are mainly polysaccharide-based. These results help to elucidate how these genes affect biofilm formation and demonstrate how mutating biofilm-related genes in SA can cause a change in biofilm composition.
(Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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