RESUMO
Staphylococcus aureus is a human commensal and pathogen that is capable of forming biofilms on a variety of host tissues and implanted medical devices. Biofilm-associated infections resist antimicrobial chemotherapy and attack from the host immune system, making these infections particularly difficult to treat. In order to gain insight into environmental conditions that influence S. aureus biofilm development, we screened a library of small molecules for the ability to inhibit S. aureus biofilm formation. This led to the finding that the polyphenolic compound tannic acid inhibits S. aureus biofilm formation in multiple biofilm models without inhibiting bacterial growth. We present evidence that tannic acid inhibits S. aureus biofilm formation via a mechanism dependent upon the putative transglycosylase IsaA. Tannic acid did not inhibit biofilm formation of an isaA mutant. Overexpression of wild-type IsaA inhibited biofilm formation, whereas overexpression of a catalytically dead IsaA had no effect. Tannin-containing drinks like tea have been found to reduce methicillin-resistant S. aureus nasal colonization. We found that black tea inhibited S. aureus biofilm development and that an isaA mutant resisted this inhibition. Antibiofilm activity was eliminated from tea when milk was added to precipitate the tannic acid. Finally, we developed a rodent model for S. aureus throat colonization and found that tea consumption reduced S. aureus throat colonization via an isaA-dependent mechanism. These findings provide insight into a molecular mechanism by which commonly consumed polyphenolic compounds, such as tannins, influence S. aureus surface colonization.
Assuntos
Antígenos de Bactérias/metabolismo , Aderência Bacteriana/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Taninos/farmacologia , Animais , Antígenos de Bactérias/genética , Biofilmes/efeitos dos fármacos , Domínio Catalítico/efeitos dos fármacos , Feminino , Ratos , Sigmodontinae , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/metabolismo , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Staphylococcus aureus/fisiologia , Chá/metabolismoRESUMO
Nineteen numerically dominant heterotrophic bacteria from a freshwater biofilm were identified by 16S ribosomal DNA gene sequencing, and their coaggregation partnerships were determined. Phylogenetic trees showed that both distantly related and closely related strains coaggregated at intergeneric, intrageneric, and intraspecies levels. One strain, Blastomonas natatoria 2.1, coaggregated with all 18 other strains and may function as a bridging organism in biofilm development.
