Work

Magnesium-Dependent Promotion of H 2 O 2 Production Increases Ecological Competitiveness of Oral Commensal Streptococci

Year: 2020

Type: article

Abstract: The pyruvate oxidase (SpxB)–dependent production of H 2 O 2 is widely distributed among oral commensal streptococci. Several studies confirmed the ability of H 2 O 2 to antagonize susceptible oral bacterial species, including caries-associated Streptococcus mutans as well as several periodontal pathobionts. Here we report a potential mechanism to bolster oral commensal streptococcal H 2 O 2 production by magnesium (Mg 2+ ) supplementation. Magnesium is a cofactor for SpxB catalytic activity, and supplementation increases the production of H 2 O 2 in vitro. We demonstrate that Mg 2+ affects spxB transcription and SpxB abundance in Streptococcus sanguinis and Streptococcus gordonii. The competitiveness of low-passage commensal streptococcal clinical isolates is positively influenced in antagonism assays against S. mutans. In growth conditions normally selective for S. mutans, Mg 2+ supplementation is able to increase the abundance of S. sanguinis in dual-species biofilms. Using an in vivo biophotonic imaging platform, we further demonstrate that dietary Mg 2+ supplementation significantly improves S. gordonii oral colonization in mice. In summary, our results support a role for Mg 2+ supplementation as a potential prebiotic to promote establishment of oral health–associated commensal streptococci.

Source: Journal of Dental Research

DOI: 10.1177/0022034520912181