title: Diversity of Streptococcus mutans strains in bacterial interspecies interactions.
abstract: Biofilms are matrix-enclosed microbial population adhere to each other and to surfaces. Compared to planktonic bacterial cells, biofilm cells show much higher levels of antimicrobial resistance. We aimed to investigate Streptococcus mutans strain diversity in biofilm formation and chlorhexidine (CHX) resistance of single S. mutans and dual S. mutans-Enterococcus faecalis biofilms. Four clinical S. mutans strains (C180-2, C67-1, HG723 and UA159) formed 24-h biofilms with or without an E. faecalis strain. These biofilms were treated for 10 min with 0.025% CHX. Biofilm formation, CHX resistance and S.mutans-E. faecalis interactions were evaluated by biomass staining, resazurin metabolism, viable count and competition agar assays. The main finding is that the presence of E. faecalis generally reduced all dual-species biofilm formation, but the proportions of S. mutans in the dual-species biofilms as well as CHX resistance displayed a clear S. mutans strain dependence. In particular, decreased resistance against CHX was observed in dual S. mutans C67-1 biofilms, while increased resistance was found in dual S. mutans UA159 biofilms. In conclusion, the interaction of S. mutans with E. faecalis in biofilms varies between strains, which underlines the importance of studying strain diversity in inter-species virulence modulation and biofilm antimicrobial resistance.
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Free University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands; Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.
authors: Xiaolan
authors: X
authors: Li
authors: Michel A
authors: MA
authors: Hoogenkamp
authors: Junqi
authors: J
authors: Ling
authors: Wim
authors: W
authors: Crielaard
authors: Dong Mei
authors: DM
authors: Deng
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002710:Chlorhexidine / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013045:Species Specificity; D013295:Streptococcus mutans / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002710:Chlorhexidine
keywords: Antimicrobial resistance; Biofilm; Dual-species; Strain diversity; Streptococcus