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Shirato M, Nakamura K, Tenkumo T, Niwano Y, Kanno T, Sasaki K, Lingström P, Örtengren U. Inhibition of tooth demineralization caused by Streptococcus mutans biofilm via antimicrobial treatment using hydrogen peroxide photolysis. Clin Oral Investig 2023; 27:739-750. [PMID: 36484848 PMCID: PMC9889499 DOI: 10.1007/s00784-022-04821-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 11/26/2022] [Indexed: 12/13/2022]
Abstract
OBJECTIVES An antimicrobial technique utilizing hydroxyl radicals generated by the photolysis of 3% H2O2 has been developed recently. The present study aimed to evaluate the effect of H2O2 photolysis treatment on tooth demineralization caused by Streptococcus mutans biofilm. MATERIALS AND METHODS To induce tooth demineralization, S. mutans biofilm was allowed to form on the maxillary first molars collected from Wistar rats via 24-h culturing. The samples were immersed in 3% H2O2 and irradiated with 365-nm LED (H2O2 photolysis treatment). Viable bacterial counts in the biofilm were evaluated immediately after treatment and after an additional 30-h culturing by colony counting. The acidogenicity of the biofilm, re-established 30 h after treatment, was assessed by measuring the pH. The effect of H2O2 photolysis treatment on tooth demineralization was assessed by measuring the depth of the radiolucent layer in micro-CT images. RESULTS H2O2 photolysis significantly reduced viable bacterial counts in the biofilm to 3.7 log colony forming units (CFU)/sample, while the untreated group had 7.9 log CFU/sample. The pH of the biofilm re-established after treatment (6.6) was higher than that of the untreated group (5.3). In line with the pH measurement, the treatment group had a significantly lower depth of radiolucent layer in dentin than the untreated group. CONCLUSIONS H2O2 photolysis treatment was effective not only in killing the biofilm-forming S. mutans but also in lowering the acidogenicity of the biofilm. Thus, this technique could inhibit tooth demineralization. CLINICAL RELEVANCE H2O2 photolysis can be applicable as a new dental caries treatment.
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Affiliation(s)
- Midori Shirato
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden ,Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-Machi, Aoba-Ku, Sendai, 980-8575 Japan
| | - Keisuke Nakamura
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-Machi, Aoba-Ku, Sendai, 980-8575 Japan
| | - Taichi Tenkumo
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo, Aoba-Ku, Sendai, 980-8575 Japan
| | - Yoshimi Niwano
- Faculty of Nursing, Shumei University, 1-1 Daigaku-Cho, Yachiyo, 276-0003 Japan
| | - Taro Kanno
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-Machi, Aoba-Ku, Sendai, 980-8575 Japan
| | - Keiichi Sasaki
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-Machi, Aoba-Ku, Sendai, 980-8575 Japan ,Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo, Aoba-Ku, Sendai, 980-8575 Japan
| | - Peter Lingström
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Ulf Örtengren
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
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Reactive Oxygen Species Production Is a Major Factor Directing the Postantibiotic Effect of Fluoroquinolones in Streptococcus pneumoniae. Antimicrob Agents Chemother 2019; 63:AAC.00737-19. [PMID: 31160286 DOI: 10.1128/aac.00737-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/26/2019] [Indexed: 11/20/2022] Open
Abstract
We studied the molecular mechanisms involved in the postantibiotic effect of the fluoroquinolones levofloxacin and moxifloxacin in Streptococcus pneumoniae Wild-type strain R6 had postantibiotic effects of 2.05 ± 0.10 h (mean ± standard deviation [SD]) and 3.23 ± 0.45 h at 2.5× and 10× MIC of levofloxacin, respectively. Moxifloxacin exhibited lower effects of 0.87 ± 0.1 and 2.41 ± 0.29 h at 2.5× and 10× MIC, respectively. Fluoroquinolone-induced chromosome fragmentation was measured at equivalent postantibiotic effects for levofloxacin (2.5× MIC) and moxifloxacin (10× MIC). After 2 h of drug removal, reductions were approximately 7-fold for levofloxacin and 3-fold for moxifloxacin, without further decreases at later times. Variations in reactive oxygen species production were detected after 4 to 6 h of drug withdrawals, with decreases ≥400-fold for levofloxacin and ≥800-fold for moxifloxacin at 6 h. In accordance, after 4 to 6 h of drug withdrawal, the levofloxacin-induced upregulation of the fatCDEB operon, introducing iron in the bacteria, decreased up to 2- to 3-fold, and the moxifloxacin-induced upregulation of several genes involved in the production of pyruvate was reduced 3- to 7-fold. In accordance, lower postantibiotic effects (up to 1 h) were observed in strain R6 ΔspxB, lacking the main enzyme involved in oxygen peroxide production, than in R6. Although no change in the recovery of chromosome fragmentation was observed between R6 and R6 ΔspxB, 3.5 × 103-fold lower reactive oxygen species production was observed in R6 ΔspxB, without changes after drug removal. These results show that reactive oxygen species are the main factors directing the postantibiotic effect of levofloxacin and moxifloxacin in S. pneumoniae.
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Photo-irradiated caffeic acid exhibits antimicrobial activity against Streptococcus mutans biofilms via hydroxyl radical formation. Sci Rep 2017; 7:6353. [PMID: 28743937 PMCID: PMC5527086 DOI: 10.1038/s41598-017-07007-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/20/2017] [Indexed: 11/23/2022] Open
Abstract
An antimicrobial technique based on photo-oxidation of caffeic acid (CA) has recently been developed, but its effect on biofilm-forming bacteria is unknown. The present study aimed to evaluate the effect of photo-irradiated CA against Streptococcus mutans (cariogenic bacteria) biofilm as it relates to hydroxyl radical formation. S. mutans biofilms grown on hydroxyapatite disks were immersed in CA solution (0–2 mg/mL) and irradiated with LED light at wavelengths of 365, 385, and 400 nm and at irradiances of 500, 1000, and 2000 mW/cm2 for 4 min. Biofilm viable bacterial counts were determined by colony counting. The yield of hydroxyl radicals generated by the LED irradiation of CA solution was quantified by electron spin resonance analysis. Of the conditions tested, the highest bactericidal effect, with a > 5-log reduction in viable bacterial counts, was obtained by irradiation of a 1 mg/mL CA solution with 385 nm LED and at an irradiance of 2000 mW/cm2. Hydroxyl radical formation was related to this bactericidal effect. The present study suggests that the antimicrobial technique based on the 385 nm LED irradiation of CA is effective against cariogenic biofilms and can be applied as an adjunctive chemotherapy for dental caries.
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Sheng H, Nakamura K, Kanno T, Sasaki K, Niwano Y. Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation. PLoS One 2015; 10:e0132445. [PMID: 26148024 PMCID: PMC4493093 DOI: 10.1371/journal.pone.0132445] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/15/2015] [Indexed: 11/21/2022] Open
Abstract
The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.
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Affiliation(s)
- Hong Sheng
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
- * E-mail:
| | - Keisuke Nakamura
- Laboratory for Redox Regulation, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Taro Kanno
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Keiichi Sasaki
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Yoshimi Niwano
- Laboratory for Redox Regulation, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
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Mokudai T, Kanno T, Niwano Y. Postantifungal-like effect of sublethal treatment of Candida albicans with acid-electrolyzed water. Arch Oral Biol 2015; 60:479-87. [PMID: 25555249 DOI: 10.1016/j.archoralbio.2014.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 10/08/2014] [Accepted: 12/10/2014] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Acid-electrolyzed water (AEW) has been applied to the treatment of oral candidiasis. We evaluated the postantifungal effect (PAFE)-like activity of AEW against Candida albicans under sublethal conditions by exposing C. albicans to dilute AEW. DESIGN The growth of C. albicans after a short-term exposure to dilute AEW was evaluated in broth and on agar culture. The involvement of reactive oxygen species (ROS) in the PAFE was examined by flow cytometric analysis with hydroxyphenyl fluorescein (HPF) as a fluorescence probe. RESULTS The dilute AEW exerted PAFE-like activity against C. albicans. ROS were produced in the cells treated with AEW diluted 16 times or fewer. The increase in HPF fluorescence after treatment with dilute AEW was cancelled by dimethyl sulfoxide, a hydroxyl radical (OH) scavenger. CONCLUSION It would be expected that the ROS, especially OH, produced in the C. albicans cells treated with sublethal dilutions of AEW could exert PAFE-like activity against the fungal cells.
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Affiliation(s)
- Takayuki Mokudai
- Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Taro Kanno
- Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Yoshimi Niwano
- Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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