Streptococcus mutans adhesion force sensing in multi-species oral biofilms

Abstract

Bacteria utilize chemical and mechanical mechanisms to sense their environment, to survive hostile conditions. In mechanical sensing, intra-bilayer pressure profiles change due to deformation induced by the adhesion forces bacteria experience on a surface. Emergent properties in mono-species Streptococcus mutans biofilms, such as extracellular matrix production, depend on the adhesion forces that streptococci sense. Here we determined whether and how salivary-conditioning film (SCF) adsorption and the multi-species nature of oral biofilm influence adhesion force sensing and associated gene expression by S. mutans. Hereto, Streptococcus oralis, Actinomyces naeslundii, and S. mutans were grown together on different surfaces in the absence and presence of an adsorbed SCF. Atomic force microscopy and RT-qPCR were used to measure S. mutans adhesion forces and gene expressions. Upon SCF adsorption, stationary adhesion forces decreased on a hydrophobic and increased on a hydrophilic surface to around 8 nN. Optical coherence tomography showed that triple-species biofilms on SCF-coated surfaces with dead S. oralis adhered weakly and often detached as a contiguous sheet. Concurrently, S. mutans displayed no differential adhesion force sensing on SCF-coated surfaces in the triple-species biofilms with dead S. oralis, but once live S. oralis were present S. mutans adhesion force sensing and gene expression ranked similar as on surfaces in the absence of an adsorbed SCF. Concluding, live S. oralis may enzymatically degrade SCF components to facilitate direct contact of biofilm inhabitants with surfaces and allow S. mutans adhesion force sensing of underlying surfaces to define its appropriate adaptive response. This represents a new function of initial colonizers in multispecies oral biofilms.

Bacterial diversity and functional analysis of severe early childhood caries and recurrence in India

“…The positive growth interaction between the OP32 with the non-biofilm forming clinical isolates show that the interspecies interaction is significant in the SECC microbiome. Further, the increased biofilm formation in co-culture of S. oralis and OP32 with the major cariogen S. mutans under high sucrose environment show the cariogenic interrelation between the species, as observed earlier 31,32 . Also high pH reduction in the dual culture S. mutans: S. oralis and S. mutans: OP32 co-culture suggests its role in acidification of oral niche.…”

Synthesis of silver nanoparticles using gum Arabic: Evaluation of its inhibitory action on Streptococcus mutans causing dental caries and endocarditis

“…In S. mutans Glucosyl transference (gtfc gtfD and gtfB) are the virulent genes for plaque formation in biofilm over the tooth surface. The inhibition of the three glucosyltransferase genes impairs the colonization and biofilm formation by S. mutans [ 30 ]. The gene gtfD lies in a distant locus from gtfB, gtfC and gbpB ( Fig.…”

“…However, it plays a role in the structure of glucans in the biofilm formed by S. mutans . The inhibition of virulence of gftB, gftC and gftD interferes with the virulence of S. mutans and its biofilm formation over teeth that induces dental enamel corrosion and dental caries [ 30 ]. The glucan binding protein gbpB is another important virulent gene-regulating antibiotic sensitivity, oxidative and osmotic stress, cell wall construction, maintaining cell shape, hydrophobic, and biofilm formation [ 31 ].…”

In Silico Selection and In Vitro Evaluation of New Molecules That Inhibit the Adhesion of Streptococcus mutans through Antigen I/II

“…These findings show the importance of the molecule fragments (9h-fluorene and Piperazine) in the adhesion inhibition, because it has been shown that bacteria have mechanisms that modify the surfaces to increase hydrophobicity and be able to adhere [ 60 , 61 ]. For this study, it was found that the 9h fluorene fragment is very important for adhesion inhibition of S. mutans , since the three molecules contain this fragment and interact with hydrophobic parts of the residues and additionally the other fragments such as 2,3 Dihydrobenzofuran in ZI-187 could be important for inhibition capacity.…”