Polyphosphate-Accumulating Bacteria: Potential Contributors to Mineral Dissolution in the Oral Cavity

Abstract

Bacteria that accumulate polyphosphates have previously been shown to dynamically influence the solubility of phosphatic minerals in marine settings and wastewater. Here, we show that dental plaque, saliva, and carious lesions all contain abundant polyphosphate-accumulating bacteria. Saturation state modeling results, informed by phosphate uptake experiments using the model organism Lactobacillus rhamnosus, which is known to inhabit advanced carious lesions, suggest that polyphosphate accumulation can lead to undersaturated conditions with respect to hydroxyapatite under some oral cavity conditions. The cell densities of polyphosphate-accumulating bacteria we observed in some regions of oral biofilms are comparable to those that produce undersaturated conditions (i.e., those that thermodynamically favor mineral dissolution) in our phosphate uptake experiments with L. rhamnosus. These results suggest that the localized generation of undersaturated conditions by polyphosphate-accumulating bacteria constitutes a new potential mechanism of tooth dissolution that may augment the effects of metabolic acid production.IMPORTANCE Dental caries is a serious public health issue that can have negative impacts on overall quality of life and oral health. The role of oral bacteria in the dissolution of dental enamel and dentin that can result in carious lesions has long been solely ascribed to metabolic acid production. Here, we show that certain oral bacteria may act as a dynamic shunt for phosphate in dental biofilms via the accumulation of a polymer known as polyphosphate—potentially mediating phosphate-dependent conditions such as caries (dental decay).

Antibacterial and Remineralization Efficacy of Casein Phosphopeptide, Glycomacropeptide Nanocomplex, and Probiotics in Experimental Toothpastes: An In Vitro Comparative Study

“…This decline in the microhardness could be attributed to the nature of the L. rhamnosus bacteria which is a phosphate accumulating bacteria that tends to accumulate polyphosphates resulting in the decline of phosphate in the surrounding which can lead to undersaturated conditions relative to the hydroxyapatite which might lead to demineralization potentials in dental plaque and lesser degrees of remineralization in the conducted study. 41 Though the inhibitory effect of group (A3) toothpaste containing probiotic against S. mutans growth was in accordance with many studies, 42 43 the remineralization capacity of this group needs prolonged studies in addition to in vivo studies to observe the actual effect of this toothpaste in oral conditions. Regarding the nGMP group (A4), the highest microhardness remineralization results were reported for this group.…”

Polyphosphate in Lactobacillus and Its Link to Stress Tolerance and Probiotic Properties

“…Owing to the relevance of lactobacilli in food and health, knowledge of the many poly-P functions in this microbial group will help to understand their physiology and interactions in bacterial communities and symbiotic relationships. These would cover positive but also negative aspects, as it has been recently described that poly-P accumulation in dental biofilm bacteria such as Lactobacillus rhamnosus may participate in teeth demineralization during carious lesion progression ( Breiland et al, 2018 ).…”

Sustained Release of Phosphates From Hydrogel Nanoparticles Suppresses Bacterial Collagenase and Biofilm Formation in vitro

“…It is known, however, that polyphosphate kinases (ppk1 and ppk2) are primarily responsible for synthesizing and hydrolyzing polyphosphates in bacteria. These enzymes, and high polyphosphate storage capacity have been confirmed in pathogens such as P. aeruginosa (Zhang et al, 2002; Racki et al, 2017), but recent studies have shown that the Enterococcus genus has a low genetic potential for accumulating and hydrolyzing polyphosphate (Breiland et al, 2018). Therefore, a possible explanation of our findings is that E. faecalis , does not have the capacity to readily break down PPi to phosphate to make it more readily bioavailable.…”