Streptococcus oligofermentans inhibits Streptococcus mutans through conversion of lactic acid into inhibitory H2O2: a possible counteroffensive strategy for interspecies competition

ABSTRACTComplex interspecies interactions occur constantly between oral commensals and the opportunistic pathogenStreptococcus mutansin dental plaque. Previously, we showed that oral commensalStreptococcus oligofermentanspossesses multiple enzymes for H2O2production, especially lactate oxidase (Lox), allowing it to out-competeS. mutans. In this study, through extensive biochemical and genetic studies, we identified a pyruvate oxidase (pox) gene inS. oligofermentans. Apoxdeletion mutant completely lost Pox activity, while ectopically expressedpoxrestored activity. Pox was determined to produce most of the H2O2in the earlier growth phase and log phase, while Lox mainly contributed to H2O2production in stationary phase. Bothpoxandloxwere expressed throughout the growth phase, while expression of theloxgene increased by about 2.5-fold when cells entered stationary phase. Since lactate accumulation occurred to a large degree in stationary phase, the differential Pox- and Lox-generated H2O2can be attributed to differential gene expression and substrate availability. Interestingly, inactivation ofpoxcauses a dramatic reduction in H2O2production from lactate, suggesting a synergistic action of the two oxidases in converting lactate into H2O2. In anin vitrotwo-species biofilm experiment, thepoxmutant ofS. oligofermentansfailed to inhibitS. mutanseven thoughloxwas active. In summary,S. oligofermentansdevelops a Pox-Lox synergy strategy to maximize its H2O2formation so as to win the interspecies competition.

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S-glutathionylation proteome profiling reveals a crucial role of a thioredoxin-like protein in interspecies competition and cariogenecity of Streptococcus mutans

PLoS Pathogens ◽

10.1371/journal.ppat.1008774 ◽

2020 ◽

Vol 16 (7) ◽

pp. e1008774

Author(s):

Zhengyi Li ◽

Chenzi Zhang ◽

Cheng Li ◽

Jiajia Zhou ◽

Xin Xu ◽

...

Keyword(s):

Streptococcus Mutans ◽

Crucial Role ◽

Interspecies Competition ◽

Proteome Profiling

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Effect of antibacterial photodynamic therapy on Streptococcus mutans plaque biofilm in vitro

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545820500224 ◽

2020 ◽

Vol 13 (06) ◽

pp. 2050022

Author(s):

Xiaoyue Liang ◽

Zhaohui Zou ◽

Zheng Zou ◽

Changyi Li ◽

Xiaoxi Dong ◽

...

Keyword(s):

Photodynamic Therapy ◽

Lactic Acid ◽

Streptococcus Mutans ◽

Antibacterial Effect ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Saline Control ◽

Control Group ◽

Plaque Biofilm

The main objective of this study is to evaluate the antibacterial effect of antibacterial photodynamic therapy (aPDT) on Streptococcus mutans (S. mutans) biofilm model in vitro. The selection of photosensitizers is the key step for the efficacy of photodynamic therapy (PDT). However, no studies have been conducted in the oral field to compare the functional characteristics and application effects of PDT mediated by various photosensitizers. In this research, the antibacterial effect of Methylene blue (MB)/650[Formula: see text]nm laser and Hematoporphyrin monomethyl ether (HMME)/532[Formula: see text]nm laser on S. mutans biofilm was compared under different energy densities to provide experimental reference for the clinical application of the two PDT. The yield of lactic acid was analyzed by Colony forming unit (CFU) and spectrophotometry, and the complete biofilm activity was measured by Confocal Laser Scanning Microscopy (CLSM) to evaluate the bactericidal effect on each group. Based on the results of CFU, the bacterial colonies formed by 30.4[Formula: see text]J/cm2 532[Formula: see text]nm MB-aPDT group and 30.4[Formula: see text]J/cm2 532[Formula: see text]nm HMME-aPDT group were significantly less than those in other groups, and the bacterial colonies in HMME-aPDT group were less than those in HMME-aPDT group. Lactic acid production in all treatment groups except the photosensitizer group was statistically lower than that in the normal saline control group. The activity of bacterial plaque biofilm was significantly decreased in the two groups treated with 30.4[Formula: see text]J/cm2 aPDT. Therefore, aPDT suitable for energy measurement can kill S. mutans plaque biofilm, and MB-aPDT is better than HMME-aPDT.

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Who will win the race in childrens' oral cavities? Streptococcus mutans or beneficial lactic acid bacteria?

Beneficial Microbes ◽

10.3920/bm2012.0055 ◽

2013 ◽

Vol 4 (3) ◽

pp. 237-245 ◽

Cited By ~ 3

Author(s):

ö.E. Güngör ◽

Z. Kırzıoğlu ◽

E. Dinçer ◽

M. Kıvanç

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Oral Cavity ◽

Streptococcus Mutans ◽

Meat Products ◽

Tooth Surface ◽

Healthy Children ◽

Bacterial Strains ◽

Adhesive Properties ◽

Meat Samples

Adhesion to oral soft and hard tissue is crucial for bacterial colonisation in the mouth. The aim of this work was to select strains of oral lactic acid bacteria that could be used as probiotics for oral health. To this end, the adhesive properties of some lactic acid bacteria were investigated. Seventeen lactic acid bacteria including two Streptococcus mutans strains were isolated from the oral cavity of healthy children, while other strains were isolated from fermented meat products. The bacterial strains were applied to teeth surfaces covered with saliva or without saliva. A significant diversity in adhesion capacity to teeth surfaces among the lactic acid bacteria was observed. Lactic acid bacteria isolated from the oral cavity adhered the best to teeth surfaces covered with saliva, whereas lactic acid bacteria isolated from fermented meat samples adhered the best to tooth surface without saliva. All strains of lactic acid bacteria were able to reduce the number of S. mutans cells, in particular on saliva-coated tooth surface. Therefore, they might have potential as probiotics for the oral cavity.

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Effect of Anti-oxidants on Growth and Lactic Acid Production by Streptococcus mutans

Journal of Dental Research ◽

10.1177/00220345850640070401 ◽

1985 ◽

Vol 64 (7) ◽

pp. 1016-1018 ◽

Cited By ~ 4

Author(s):

L.I. Kupp ◽

S. Rosen ◽

F.M. Beck

Keyword(s):

Lactic Acid ◽

Streptococcus Mutans ◽

Acid Production ◽

Lactic Acid Production

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Persistence of Streptococcus mutans in Stationary-Phase Batch Cultures and Biofilms

Applied and Environmental Microbiology ◽

10.1128/aem.70.10.6181-6187.2004 ◽

2004 ◽

Vol 70 (10) ◽

pp. 6181-6187 ◽

Cited By ~ 28

Author(s):

John A. Renye ◽

Patrick J. Piggot ◽

Lolita Daneo-Moore ◽

Bettina A. Buttaro

Keyword(s):

Lactic Acid ◽

Dental Caries ◽

Stationary Phase ◽

Streptococcus Mutans ◽

Defined Medium ◽

Etiological Agent ◽

Chemically Defined Medium ◽

Batch Cultures ◽

Sucrose Starvation ◽

Light Staining

ABSTRACT Streptococcus mutans is a member of oral plaque biofilms and is considered the major etiological agent of dental caries. We have characterized the survival of S. mutans strain UA159 in both batch cultures and biofilms. Bacteria grown in batch cultures in a chemically defined medium, FMC, containing an excess of glucose or sucrose caused the pH to decrease to 4.0 at the entry into stationary phase, and they survived for about 3 days. Survival was extended up to 11 days when the medium contained a limiting concentration of glucose or sucrose that was depleted by the time the bacteria reached stationary phase. Sugar-limited cultures maintained a pH of 7.0 throughout stationary phase. Their survival was shortened to 3 days by the addition of exogenous lactic acid at the entry into stationary phase. Sugar starvation did not lead to comparable survival in biofilms. Although the pH remained at 7.0, bacteria could no longer be cultured from biofilms 4 days after the imposition of glucose or sucrose starvation; BacLight staining results did not agree with survival results based on culturability. In both batch cultures and biofilms, survival could be extended by the addition of 0.5% mucin to the medium. Batch survival increased to an average of 26 (±8) days, and an average of 2.7 × 105 CFU per chamber were still present in biofilms that were starved of sucrose for 12 days.

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In vitro Antibacterial Activity of an FDA-Approved H+-ATPase Inhibitor, Bedaquiline, Against Streptococcus mutans in Acidic Milieus

Frontiers in Microbiology ◽

10.3389/fmicb.2021.647611 ◽

2021 ◽

Vol 12 ◽

Author(s):

Meng Zhang ◽

Wenqian Yu ◽

Shujing Zhou ◽

Bing Zhang ◽

Edward Chin Man Lo ◽

...

Keyword(s):

Lactic Acid ◽

Streptococcus Mutans ◽

Lactic Acid Production ◽

Extracellular Polysaccharide ◽

Dependent Manner ◽

Atpase Inhibitor ◽

Periodontal Ligament Stem Cells ◽

Broth Microdilution Method ◽

Oral Pathogens

BackgroundDental caries is an acid-related disease. Current anti-caries agents mainly focus on the bacteriostatic effect in a neutral environment and do not target acid-resistant microorganisms related to caries in acidic milieus.ObjectivesTo assess the in vitro antibacterial activities of bedaquiline against oral pathogens in acidic milieus.MethodsStreptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius were used to prepare the mono-/multiple suspension and biofilm. The MIC and IC50 of bedaquiline against S. mutans were determined by the broth microdilution method. Bedaquiline was compared regarding (i) the inhibitory activity in pH 4–7 and at different time points against planktonic and biofilm; (ii) the effect on the production of lactic acid, extracellular polysaccharide, and pH of S. mutans biofilm; (iii) the cytotoxicity effects; and (iv) the activity on H+-ATPase enzyme of S. mutans.ResultsIn pH 5 BHI, 2.5 mg/L (IC50) and 4 mg/L (MIC) of bedaquiline inhibited the proliferation and biofilm generation of S. mutans and Mix in a dose-dependent and time-dependent manner, but it was invalid in a neutral environment. The lactic acid production, polysaccharide production, and pH drop range reduced with the incorporation of bedaquiline in a pH 5 environment. Its inhibitory effect (>56 mg/L) against H+-ATPase enzyme in S. mutans and its non-toxic effect (<10 mg/L) on periodontal ligament stem cells were also confirmed.ConclusionBedaquiline is efficient in inhibiting the proliferation and biofilm generation of S. mutans and other oral pathogens in an acidic environment. Its high targeting property and non-cytotoxicity also promote its clinical application potential in preventing caries. Further investigation of its specific action sites and drug modification are warranted.

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Rapid procedure for acid adaptation of oral lactic-acid bacteria and further characterization of the response

Canadian Journal of Microbiology ◽

10.1139/m97-019 ◽

1997 ◽

Vol 43 (2) ◽

pp. 143-148 ◽

Cited By ~ 17

Author(s):

Yousheng Ma ◽

Timothy M. Curran ◽

Robert E. Marquis

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Streptococcus Mutans ◽

Acid Tolerance ◽

Growth Media ◽

Oral Microbiota ◽

Adaptive Responses ◽

Acid Adaptation ◽

General Importance ◽

Time Required

Acid-adaptive responses could be induced readily in oral lactic-acid bacteria by growing them in batch cultures with excess sugar or more conveniently and rapidly by transferring cells to acidified growth media for the time required for biomass doubling. The response of Streptococcus mutans GS-5 was induced in a progressive rather than all-or-nothing way, and the extent of acid tolerance was inversely related to the pH of the inducing medium over a range from 8.5 to 5. The weak acids fluoride, acetate, or lactate did not measurably enhance acid adaptation, and so the response did not appear to depend primarily on changes in ΔpH or the proton motive force across the cell membrane. Transcription and translation to form new proteins did appear to be necessary, as indicated by inhibition of adaptation by rifampin or chloramphenicol and by lack of adaptation by cells suspended in phosphate buffer at pH 5. Streptococcus salivarius and Lactobacillus casei were acid adapted by the rapid method, and the method appeared to be generally useful for oral lactic-acid bacteria. The rapid induction of the response in multiple oral lactic-acid bacteria suggests that it is of general importance for maintaining a diversity of organisms in the oral microbiota, which is regularly subjected to acid stresses.Key words: acid adaptation, oral lactic-acid bacteria, Streptococcus mutans.

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