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OBJECTIVE: Epigallocatechin-3-gallate (EGCG), a catechin abundant in green tea, exhibits antibacterial activity. In this study, the antimicrobial effects of EGCG on periodontal disease-associated bacteria (Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Fusobacterium nucleatum, and Fusobacterium periodontium) were evaluated and compared with its effects on Streptococcus mutans, a caries-associated bacterium. RESULTS: Treatment with 2 mg/ml EGCG for 4 h killed all periodontal disease-associated bacteria, whereas it only reduced the viable count of S. mutans by about 40 %. Regarding growth, the periodontal disease-associated bacteria were more susceptible to EGCG than S. mutans, based on the growth inhibition ring test. As for metabolism, the 50 % inhibitory concentration (IC50) of EGCG for bacterial metabolic activity was lower for periodontal disease-associated bacteria (0.32-0.65 mg/ml) than for S. mutans (1.14 mg/ml). Furthermore, these IC50 values were negatively correlated with the growth inhibition ring (r = -0.73 to -0.86). EGCG induced bacterial aggregation at the following concentrations: P. gingivalis (>0.125 mg/ml), F. periodonticum (>0.5 mg/ml), F. nucleatum (>1 mg/ml), and P. nigrescens (>2 mg/ml). S. mutans aggregated at an EGCG concentration of > 1 mg/ml. CONCLUSION: EGCG may help to prevent periodontal disease by killing bacteria, inhibiting bacterial growth by suppressing bacterial metabolic activity, and removing bacteria through aggregation.
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To explore the potential storage and safety of drinking leftover bottled tea beverages from various manufacturers after direct drinking from bottles, we conducted a screening experiment on the growth of salivary bacteria in plastic bottles of tea. The diluted saliva samples from 10 participants were inoculated into the test bottled beverages, which resulted in bacteria, particularly former members of the genus Lactobacillus, growing in some green tea beverages with a neutral pH. In contrast, tea beverages with less bacterial growth contained Streptococcus spp., and the leftovers may be safe to store and drink again.
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INTRODUCTION: The purpose of this study was to investigate the effects of nitrate and nitrite on the pH-lowering activity of human plaque, the nitrite-producing and -degrading activities of human plaque, and their correlation. METHODS: Nitrate and nitrite were added to human plaque suspensions collected from the buccal aspect of maxillary molars of patients visiting a general dental clinic, and changes in pH were measured with and without glucose addition. Nitrite-producing and -degrading activities were evaluated by adding nitrate and nitrite to the plaque suspension and measuring the increase and decrease in nitrite with Griess reagent, respectively. RESULTS: The addition of nitrate inhibited both endogenous and glucose-induced plaque pH-lowering. The addition of glucose enhanced the production of nitrite from nitrate by about 3.3-fold. The addition of nitrite also inhibited endogenous plaque pH-lowering, but the addition of glucose promoted nitrite degradation by only about 1.1-fold. Nitrite-producing activity was positively correlated with age, but not with nitrite-degrading activity. CONCLUSION: This study revealed that nitrite was produced from nitrate and inhibited the pH-lowering activity of human plaque, which may contribute to caries control. Both nitrite-producing and -degrading activities occurred in human plaque, but no correlation was found between them. Furthermore, nitrite production was enhanced by glucose metabolism, which may function as a self-regulatory mechanism (resilience) to prevent excessive acidification by glucose metabolism.
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OBJECTIVES: To determine the characteristics of the endodontic microbiome. MATERIAL AND METHODS: Saliva, plaque, and infected root canal wall dentin of two teeth suffering from apical periodontitis were harvested from a 58-year-old man. Bacterial DNA was extracted from each sample, and 16S rRNA gene analysis targeting the V3-V4 region was conducted on the Illumina MiSeq platform using QIIME2. The functional potential of the microbiomes was inferred using PICRUSt2. RESULTS: The four microbiomes were different in structure and membership, yet the nine most abundant metabolic pathways were common among them. The two endodontic microbiomes were more anaerobic, rich in Firmicutes, and scarce in Actinobacteriota and Proteobacteria, compared with saliva and plaque microbiomes. Their profiles were dissimilar despite their clinical and radiographic similarities. CONCLUSIONS: The endodontic microbiomes were anaerobic, rich in Firmicutes, scarce in Actinobacteriota and Proteobacteria, and considerably varied within an individual.
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Placa Dental , Microbiota , Periodontitis Periapical , Masculino , Humanos , Persona de Mediana Edad , Saliva , ARN Ribosómico 16S/genética , Microbiota/genéticaRESUMEN
Green tea-derived catechins, which can be divided into galloylated (epicatechin gallate: ECG, epigallocatechin gallate: EGCG) and non-galloylated (catechin: C, epicatechin: EC, epigallocatechin: EGC) catechins, are considered to be the main contributors to the caries control potential of green tea. In this study, we intended to compare the antimicrobial effects of these representative green tea-derived catechins and their combined effects with fluoride on the acid production and aggregation of Streptococcus mutans. The effects of different catechins on the growth, aggregation and acid production of S. mutans, and the combined effect of catechins and potassium fluoride (2 m
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Antiinfecciosos , Catequina , Humanos , Té/química , Catequina/farmacología , Catequina/análisis , Catequina/metabolismo , Streptococcus mutans/metabolismo , Fluoruros/farmacología , Simulación del Acoplamiento MolecularRESUMEN
Increasing evidence suggests that aerobic glycolysis is related to the progression of oral squamous cell carcinoma (OSCC). Hence, we focused on glycolysis-related gene sets to screen for potential therapeutic targets for OSCC. The expression profiles of OSCC samples and normal controls were obtained from The Cancer Genome Atlas (TCGA). Then, the differentially expressed gene sets were selected from the official GSEA website following extraction of the differentially expressed core genes (DECGs). Subsequently, we tried to build a risk model on the basis of DECGs to predict the prognosis of OSCC patients via Cox regression analysis. Furthermore, crucial glycolysis-related genes were selected to explore their biological roles in OSCC. Two active glycolysis-related pathways were acquired and 66 DECGs were identified. Univariate Cox regression analysis showed that six genes, including HMMR, STC2, DDIT4, DEPDC1, SLC16A3, and AURKA, might be potential prognostic factors. Subsequently, a risk formula consisting of DEPDC1, DDIT4, and SLC16A3 was established on basis of the six molecules. Furthermore, DEPDC1 was proven to be related to advanced stage cancer and lymph node metastasis. Moreover, functional experiments suggested that DEPDC1 promoted the aerobic glycolysis, migration, and invasion of OSCC via the WNT/ß-catenin pathway. The risk score according to glycolysis-related gene expression might be an independent prognostic factor in OSCC. In addition, DEPDC1 was identified as playing a carcinogenic role in OSCC progression, suggesting that DEPDC1 might be a novel biomarker and therapeutic target for OSCC.
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Carcinoma de Células Escamosas , Neoplasias de la Boca , Carcinoma de Células Escamosas de Cabeza y Cuello , Humanos , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Proteínas Activadoras de GTPasa/metabolismo , Neoplasias de Cabeza y Cuello/genética , Neoplasias de la Boca/patología , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Vía de Señalización Wnt/genéticaRESUMEN
Combining fluoride and antimicrobial agents enhances regulation of acid and exopolysaccharide production by biofilms. The combination also weakens the acidogenic and aciduric bacteria that contribute to caries, achieving stronger caries-controlling effects with lower concentrations of fluoride. In previous studies, antimicrobial peptide GH12 has been shown to inhibit lactic acid and exopolysaccharide synthesis in various cariogenic biofilm models, and reduce the proportion of acidogenic bacteria and Keyes caries scores in a rat caries model. The current study aimed to elucidate the effect of a combination of low concentrations of sodium fluoride (NaF) and GH12 and to determine the mechanism by which GH12/NaF combination controls caries. The GH12/NaF combination contained 8 mg/L GH12 and 250 ppm NaF. A rat caries model was built, and rat dental plaque was sampled and cultivated on bovine enamel slabs in vitro and subjected to short-term treatment (5 min, 3 times/day). The caries-controlling effects were evaluated using Keyes scoring and transverse microradiography. The results showed that the GH12/NaF combination significantly decreased the onset and development of dental caries, as well as mineral content loss and lesion depth in vitro (p < 0.05). For the caries-controlling mechanisms, 16S rRNA sequencing of in vivo dental plaque revealed that populations of commensal bacteria Rothia spp. and Streptococcus parasanguinis increased in the GH12/NaF group. In contrast, Veillonella, Lactobacillus, and Streptococcus mutans decreased. Furthermore, the GH12/NaF combination significantly reduced biomass, lactic acid, and exopolysaccharides production of in vitro biofilm (p < 0.05). Overall, fluoride and GH12 efficiently arrested caries development and demineralization by regulating the microbiota and suppressing acid and exopolysaccharide production in biofilms.
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Péptidos Antimicrobianos , Caries Dental , Placa Dental , Animales , Bovinos , Ratas , Péptidos Antimicrobianos/farmacología , Péptidos Antimicrobianos/uso terapéutico , Biopelículas , Caries Dental/tratamiento farmacológico , Caries Dental/prevención & control , Caries Dental/microbiología , Susceptibilidad a Caries Dentarias , Placa Dental/tratamiento farmacológico , Placa Dental/microbiología , Fluoruros/farmacología , Ácido Láctico , ARN Ribosómico 16S , Fluoruro de Sodio/farmacología , Streptococcus mutansRESUMEN
Dental caries is associated with caries-related streptococci and antimicrobial agents have been widely used for caries control, but troubled by antibiotic resistance. This study aimed to investigate the intrinsic and acquired resistance of caries-related streptococci to antimicrobial peptide GH12, which was proven promising for caries control, and preliminarily explore the phenotypic changes and whole genome of stable acquired resistant strains. In this study, susceptibility assays and resistance assays were performed, followed by stability assays of resistance, to evaluate the intrinsic resistance and the potential resistance of caries-related streptococci. Then, the phenotypic changes of the stable acquired resistant strain were explored. The whole genome of the resistant strain was sequenced and analyzed by second-generation and third-generation high-throughput sequencing technologies. Streptococcus gordonii and Streptococcus sanguinis were intrinsically resistant to GH12 compared to cariogenic Streptococcus mutans. Acquired GH12 resistance in one S. sanguinis and four S. mutans clinical strains was transient but stable in one S. mutans strain (COCC33-14). However, acquired resistance to daptomycin (DAP) and chlorhexidine in all strains was stable. Furthermore, the COCC33-14 showed cross-resistance to DAP and delayed growth rates and a lower population. However, no drug-resistant gene mutation was detected in this strain, but 6 new and 5 missing genes were found. Among them, annotation of one new gene (gene 1782|COCC33-14R) is related to the integral component of the membrane, and one missing gene rpsN is associated with the metabolism and growth of bacteria. The results indicate that stable resistant mutants of caries-related streptococci could hardly be selected by exposure to consecutive sublethal GH12, but the risk still existed. Resistance in COCC33-14R is mainly related to changes in the cell envelope.
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Antiinfecciosos , Daptomicina , Caries Dental , Antiinfecciosos/farmacología , Péptidos Antimicrobianos , Biopelículas , Clorhexidina , Susceptibilidad a Caries Dentarias , Resistencia a Medicamentos , Humanos , Streptococcus/genética , Streptococcus mutansRESUMEN
OBJECTIVES: Breast milk is a valuable and useful source of nutrition; however, surplus milk is routinely discarded for hygiene reasons despite an unclear scientific basis. Here, we profiled the microbiota of expressed breast milk before and after feeding with an artificial nipple and examined the bacterial survival in breast milk stored at 4 °C. METHODS: Eleven mother-baby pairs were included in the study. Samples of expressed breast milk were collected before and after feeding with an artificial nipple and examined both immediately (0 h) and after storage for 3 and 12 h at 4 °C. Each sample was inoculated onto a blood agar plate and incubated anaerobically and aerobically at 37 °C. Genomic DNA was extracted from individual bacterial colonies, which were identified by 16S rRNA gene sequencing. RESULTS: Before feeding, the bacterial counts at 0 and 12 h were (1.4 ± 1.6) × 105 colony-forming units (CFU)/mL and (1.4 ± 0.6) × 105 CFU/mL, respectively. Staphylococcus (47.7% and 41.9%, respectively), Cutibacterium (20.7% and 36.0%, respectively), and Streptococcus (16.1% and 6.6%, respectively) were identified among the samples. In contrast, after feeding, the bacterial counts at 0 and 12 h were (2.7 ± 1.7) × 105 CFU/mL and (2.1 ± 2.5) × 105 CFU/mL, respectively. Staphylococcus (30.1% and 37.4%, respectively), Cutibacterium (11.7% and 31.7%, respectively), and Streptococcus (41.5% and 25.2%, respectively), were identified among the samples. CONCLUSIONS: Bacteria were present in the breast milk before feeding. Although the main component of the microbiota shifted from Staphylococcus to Streptococcus species after feeding, these results suggest that surplus expressed breast milk may be preserved safely in a refrigerator for at least 12 h after feeding with an artificial nipple.
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Microbiota , Leche Humana , Humanos , Lactante , Femenino , Leche Humana/microbiología , ARN Ribosómico 16S/genética , Pezones , Microbiota/genética , Bacterias/genética , Streptococcus/genéticaRESUMEN
This study aimed to characterize commensal microbiota on the skin before and after wearing masks, and to characterize the microbiota on the surface of used masks after 1 week of drying. From the 13 human subjects (age range, 19-26 years), mean bacterial concentrations of (6.1 ± 11.0) × 105 and (1.0 ± 1.4) × 106 colony-forming units (CFU)/mL were recovered from the skin of the buccal areas wiped with a sterile cotton swab before and after wearing non-woven fabric masks for 8 h, respectively. Furthermore (3.4 ± 4.9) × 104 CFU/mL of bacteria were recovered from the mask surfaces. The bacteria contained in the masks, which consisted mainly of Cutibacterium acnes and Staphylococcus epidermidis/aureus, virtually disappeared after drying the masks indoors for 1 week.
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Máscaras , Microbiota , Textiles , Adulto , Humanos , Propionibacterium acnes , Staphylococcus aureus , Adulto JovenRESUMEN
OBJECTIVES: The survival of bacteria in the sports drink and orange juice remaining in and at the mouth of bottles after direct drinking was examined after immediately drinking and incubation at 37 °C for 24 h. METHODS: Nine healthy participants were asked to drink approximately 100 mL of a plastic bottled sports drink or orange juice. The samples were cultured anaerobically at 37 °C for 7 days. Genomic DNA was extracted from the resulting individual colonies, and bacterial species were identified using 16 S rRNA gene sequencing. RESULTS: The mean amount of bacteria in the remaining sports drink and orange juice, immediately after drinking, were (1.6 ± 2.3) × 103 colony-forming units (CFU)/mL and (2.9 ± 3.3) × 103 CFU/mL, respectively. Additionally, bacteria recovered from the mouths of the sports drink and orange juice bottles were (2.5 ± 5.5) × 104 CFU/mL and (5.8 ± 2.4) × 103 CFU/mL, respectively. Oral bacteria, such as Streptococcus, Actinomyces, Neisseria, and Rothia were found to be transferred in the sports drink and orange juice, and the bacteria were scarcely detected after incubation at 37 °C for 24 h. CONCLUSIONS: The bacterial levels differed significantly from the previously reported levels in bottled tea 24 h after drinking, suggesting that remaining drinks with low pH levels can be preserved for a longer period.
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Citrus sinensis , Microbiota , Humanos , Microbiota/genética , Jugos de Frutas y Vegetales , Boca , PlásticosRESUMEN
BACKGROUND: Bone metastases in breast cancer patients are a common concern for medical doctors and dentists. Bone-modifying agents, which are necessary to prevent skeletal-related events (SREs), are associated with osteonecrosis of the jaw as an adverse side effect. Hypersensitivity to alcohol is an unfavorable response caused by deficiency of aldehyde dehydrogenase-2 (ALDH2) activity. Inactive ALDH2 is associated with osteoporosis, but its influence on bone metastases is unclear. The aim of our study was to evaluate the effects of alcohol sensitivity on bone metastases and SREs in primary operable breast cancer patients. METHODS: We retrospectively analyzed patients who were administered docetaxel, an anti-tumor agent, for histologically diagnosed breast cancer between April 2004 and September 2015. Alcohol sensitivity was assessed based on medical records of hypersensitivity to alcohol. The primary endpoint was time to bone metastases and the secondary endpoint was time to first SRE from the initial docetaxel administration. Data were stratified by alcohol sensitivity and tumor stages, and differences were estimated by the Kaplan-Meier method. Prognostic risk factors were analyzed by the multivariate Cox proportional hazards model. RESULTS: The median follow-up period of patients with high sensitivity to alcohol (n = 45) was 54 months and that for those with low sensitivity (n = 287) was 64 months. Stratification by alcohol sensitivity revealed that tumor stage exhibited significant correlations with the cumulative incidence of bone metastases in low-sensitivity patients; however, no differences were found in high-sensitivity patients. In multivariate analysis, alcohol sensitivity was a significant prognostic risk factor for bone metastases (HR 2.721, 95% CI 1.268-5.841, P = 0.010). CONCLUSION: Alcohol sensitivity may be a prognostic risk factor for bone metastases. More detailed genetic investigations and metabolic analyses are needed.
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Neoplasias Óseas , Neoplasias de la Mama , Aldehído Deshidrogenasa Mitocondrial , Neoplasias Óseas/secundario , Huesos/patología , Neoplasias de la Mama/patología , Difosfonatos/uso terapéutico , Docetaxel/uso terapéutico , Femenino , Humanos , Estudios RetrospectivosRESUMEN
Metformin is a metabolic disruptor, and its efficacy and effects on metabolic profiles under different oxygen and nutrient conditions remain unclear. Therefore, the present study examined the effects of metformin on cell growth, the metabolic activities and consumption of glucose, glutamine, and pyruvate, and the intracellular ratio of nicotinamide adenine dinucleotide (NAD+) and reduced nicotinamide adenine dinucleotide (NADH) under normoxic (21% O2) and hypoxic (1% O2) conditions. The efficacy of metformin with nutrient removal from culture media was also investigated. The results obtained show that the efficacy of metformin was closely associated with cell types and environmental factors. Acute exposure to metformin had no effect on lactate production from glucose, glutamine, or pyruvate, whereas long-term exposure to metformin increased the consumption of glucose and pyruvate and the production of lactate in the culture media of HeLa and HaCaT cells as well as the metabolic activity of glucose. The NAD+/NADH ratio decreased during growth with metformin regardless of its efficacy. Furthermore, the inhibitory effects of metformin were enhanced in all cell lines following the removal of glucose or pyruvate from culture media. Collectively, the present results reveal that metformin efficacy may be regulated by oxygen conditions and nutrient availability, and indicate the potential of the metabolic switch induced by metformin as combinational therapy.
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Glucosa/metabolismo , Glutamina/metabolismo , Metabolómica/métodos , Metformina/farmacología , NAD/metabolismo , Ácido Pirúvico/metabolismo , Línea Celular Tumoral , Proliferación Celular , Medios de Cultivo/química , Células HeLa , Humanos , Ácido Láctico/metabolismo , Oxígeno/metabolismo , Hipoxia TumoralRESUMEN
OBJECTIVE: The oxygen concentration within cancer tissue is known to be low, but is expected to increase rapidly when oxygen is supplied by angiogenesis and hematogenous metastasis, suggesting that rapid increases in oxygen levels might influence cancer cell physiology. Therefore, we investigated the effects of oxygen concentration fluctuations on the glucose metabolism of cancer cells. METHODS: The glucose metabolism of oral squamous cell carcinoma (HSC-2 and HSC-3) and normal epithelial (HaCaT) cells cultured under normoxic (21% oxygen) or hypoxic (1% oxygen) conditions was measured using a pH-stat system under normoxic or hypoxic conditions. The acidic end-products and reactive oxygen species (ROS) generated by glucose metabolism were also measured. RESULTS: Under normoxic conditions, the metabolic activity of hypoxically cultured cancer cells was significantly increased, and the production of acids other than lactate was upregulated, while the normal cells did not respond to rapid increases in oxygen levels. ROS production was higher in normoxic conditions in all cells, especially the hypoxically cultured HSC-3 cells. CONCLUSIONS: Rapid increases in oxygen levels might enhance the glucose metabolism of hypoxically cultured cancer cells by mainly activating the TCA cycle and electron transport system, which might activate cancer cells through the ATP and ROS generation.
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Hipoxia de la Célula/fisiología , Glucosa/metabolismo , Neoplasias de la Boca/metabolismo , Oxígeno/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Adenosina Trifosfato/metabolismo , Línea Celular Tumoral , Humanos , Ácido Láctico/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
OBJECTIVES: Profiling of oral microbiota has traditionally been performed using conventional methods. These methods are relatively time-consuming and labor-intensive. Metagenomic analysis of oral microbiota using high-speed next-generation sequencing is a highly promising technology. However, it is expensive. This study sought to develop a simple and cost-effective profiling method for oral microbiota using 16S rRNA gene polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of PCR-amplified 16S ribosomal RNA genes. METHODS: Oral isolates of 59 bacterial species from human saliva, including Streptococcus, Actinomyces, and Veillonella, were cultured anaerobically on CDC Anaerobe 5% sheep blood agar plates. Genomic DNA was extracted from single colonies and 16S rRNA genes were PCR-amplified using the 27F and 1492R universal primers. The PCR products were purified and characterized by single digestion with HpaII restriction endonuclease. 16S rRNA gene sequences were obtained from the GenBank database, and the expected restriction profiles were compared with the RFLP patterns obtained from agarose gel electrophoresis. RESULTS: Sixty-five RFLP patterns were obtained from 27 genera and 59 species. The expected fragment sizes of these species were calculated based on GenBank 16S rRNA gene sequences. Fifty-nine patterns were obtained from the analysis of GenBank sequences. The RFLP patterns produced with HpaII distinguished many oral bacterial species. RFLP patterns enabling identification of oral bacteria were generated. The 16S rRNA gene PCR-RFLP analysis did not require expensive equipment and reagents and was cost-effective. CONCLUSION: PCR-RFLP analysis based on 16S rRNA genes could be an alternative method for oral microbiota analysis in smaller laboratories.
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Microbiota , Boca/microbiología , Cartilla de ADN , Humanos , Microbiota/genética , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , ARN Ribosómico 16S/genéticaRESUMEN
It has been speculated that oral bacteria can be transferred to tea in plastic bottles when it is drunk directly from the bottles, and that the bacteria can then multiply in the bottles. The transfer of oral bacteria to the mouth of bottles and bacterial survival in the remaining tea after drinking directly from bottles were examined immediately after drinking and after storage at 37 °C for 24 h. Twelve healthy subjects (19 to 23 years of age) were asked to drink approximately 50 mL of unsweetened tea from a plastic bottle. The mouths of the bottles were swabbed with sterile cotton, and the swabs and the remaining tea in the bottles were analyzed by anaerobic culture and 16S rRNA gene sequencing. Metagenomic analysis of the 16S rRNA gene was also performed. The mean amounts of bacteria were (1.8 ± 1.7) × 104 colony-forming units (CFU)/mL and (1.4 ± 1.5) × 104 CFU/mL at the mouth of the bottles immediately after and 24 h after drinking, respectively. In contrast, (0.8 ± 1.6) × 104 CFU/mL and (2.5 ± 2.6) × 106 CFU/mL were recovered from the remaining tea immediately after and 24 h after drinking, respectively. Streptococcus (59.9%) were predominant at the mouth of the bottles immediately after drinking, followed by Schaalia (5.5%), Gemella (5.5%), Actinomyces (4.9%), Cutibacterium (4.9%), and Veillonella (3.6%); the culture and metagenomic analyses showed similar findings for the major species of detected bacteria, including Streptococcus (59.9%, and 10.711%), Neisseria (1.6%, and 24.245%), Haemophilus (0.6%, and 15.658%), Gemella (5.5%, and 0.381%), Cutibacterium (4.9%, and 0.041%), Rothia (2.6%, and 4.170%), Veillonella (3.6%, and 1.130%), Actinomyces (4.9%, and 0.406%), Prevotella (1.6%, and 0.442%), Fusobacterium (1.0%, and 0.461%), Capnocytophaga (0.3%, and 0.028%), and Porphyromonas (1.0%, and 0.060%), respectively. Furthermore, Streptococcus were the most commonly detected bacteria 24 h after drinking. These findings demonstrated that oral bacteria were present at the mouth of the bottles and in the remaining tea after drinking.
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Background:Many previous studies have focused on the acetaldehyde produced from ethanol by oral bacteria as a risk factor for oral cancer. Most of these studies involved low ethanol concentrations (ca. 10 mM), but oral bacteria are exposed to a wide range of ethanol concentrations (100-10,000 mM) when alcoholic beverages are consumed. In contrast, ethanol is widely used at high concentrations (> 5,000 mM) as an antiseptic/disinfectant, suggesting that ethanol has bifacial biological effects; i.e. it acts as both a metabolic substrate for bacterial acetaldehyde production and an antimicrobial agent. Materials and methods:We examined the acetaldehyde production from ethanol by oral streptococci and the effects of ethanol exposure on the growth and viability of these bacteria at a wide range of ethanol concentrations (10-10,000 mM). Results:Acetaldehyde production was the highest at an ethanol concentration of 2,000 mM (2.1-48-fold higher than that seen at an ethanol concentration of 10 mM). Bacterial growth was inhibited by > 1,000 mM of ethanol, and the bacteria did not seem viable in the presence of > 5,000 mM of ethanol, although they still produced acetaldehyde. Conclusion:Ethanol has bifacial biological effects, and the concentration ranges of these effects overlap.
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BACKGROUND: Removal of oral biofilm from the oral mucosa is essential for preventing risk of respiratory and gastrointestinal infection in elderly people. Currently, no device is available which can remove oral biofilm from oral mucosa effectively and safely. Therefore, the effectiveness and safety of the Micro Scale Mist UNIT (MSM-UNIT), a newly developed dental plaque removal device utilizing high speed sprays of fine water droplets, were evaluated for biofilm removal, including the rate and surface roughness for simulated tooth surface and mucous membrane. METHODS: Simulated tooth and oral mucosa coated with an artificial biofilm of Streptococcus mutans were used for evaluation of effectiveness, with uncoated substrates as the controls. The MSM-UNIT and a conventional air ablation device were operated under recommended instructions. The effectiveness was evaluated from the rate of removal of the biofilm, and the safety was evaluated from the damage observed by scanning electron microscope and surface roughness. RESULTS: The biofilm removal rate of the MSM-UNIT was significantly higher than that of AIRFLOW. Little damage was observed in the area treated by the MSM-UNIT. The surface roughness of the MSM-UNIT treated area on simulated tooth surface and oral mucosa showed no significant difference to the control area. In contrast, cracks and powder were observed in the area treated by AIRFLOW. In particular, the surface roughness of the AIRFLOW treated area for Toughsilon was significantly larger than that of the control. CONCLUSIONS: The MSM-UNIT could be used safely and effectively for removing biofilm not only on simulated tooth surfaces but also simulated mucous membrane. The MSM-UNIT has no harmful effect on teeth or oral mucosa, and may be used for comprehensive oral care for patients during nursing care and the perioperative period.
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Placa Dental , Anciano , Biopelículas , Placa Dental/prevención & control , Humanos , Streptococcus mutans , Propiedades de SuperficieRESUMEN
It has been suggested that green tea-derived epigallocatechin gallate (EGCG), which has antimicrobial properties, might help prevent dental caries. However, the detailed properties of EGCG remain unclear. In this study, the antimicrobial properties of EGCG were evaluated by examining its bactericidal activity, its inhibitory effects against bacterial growth, acid production, acidic end-product formation, and sugar uptake (phosphoenolpyruvate-dependent phosphotransferase system, PEP-PTS activity), and its effects on bacterial aggregation, using monocultured planktonic cells of Streptococcus mutans and non-mutans streptococci. Coincubating S. mutans with EGCG (1 mg/mL) for 4 h had no bactericidal effects, while it decreased the growth and acid production of S. mutans by inhibiting the activity of the PEP-PTS. EGCG (2 mg/mL) caused rapid bacterial cell aggregation and had reduced the optical density of S. mutans cell suspension by 86.7% at pH 7.0 and 90.7% at pH 5.5 after 2 h. EGCG also reduced the acid production of non-mutans streptococci, including S. sanguinis, S. gordonii, and S. salivarius, and promoted the aggregation of these non-mutans streptococci. Furthermore, these antimicrobial effects of short-term EGCG treatment persisted in the presence of saliva. These results suggest that EGCG might have short-term antibacterial effects on caries-associated streptococci in the oral cavity.
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Catequina , Caries Dental , Biopelículas , Catequina/análogos & derivados , Catequina/farmacología , Caries Dental/prevención & control , Humanos , Streptococcus mutans , TéRESUMEN
OBJECTIVES: To clarify the characteristics and growth of bacteria that may infiltrate liquid baby formula during feeding and after storage for more than 3 h, the transfer of oral bacteria through artificial nipples, and bacterial survival in liquid baby formula and a baby drink were examined immediately after drinking and after storage at 4 °C for 12 h and 24 h. METHODS: Thirteen human subjects (aged 19-24 years) were asked to drink approximately 50 mL of liquid baby formula and a baby drink, via the artificial nipple of a baby bottle. Samples of the remaining liquid after storage at 4 °C for 12 h and 24 h were inoculated onto blood agar plates and incubated anaerobically at 37 °C for 7 days. Genomic DNA was extracted from individual colonies, and the bacterial species were identified by 16S rRNA gene sequencing. RESULTS: The mean concentrations of bacteria in the liquid baby formula were (2.6 ± 2.8) × 104 and (4.1 ± 6.6) × 104 colony-forming unit/mL after storage at 4 °C for 12 h and 24 h, respectively. Streptococcus (43.2%), Veillonella (9.3%), and Schaalia (8.2%) species were recovered from the remaining liquid baby formula after storage at 4 °C for 12 h. In contrast, no bacteria were detected in the remaining baby drink after storage at 37 °C for 24 h. CONCLUSIONS: The levels of bacteria immediately after drinking and after storage at 4 °C for 12 h or 24 h were similar, suggesting that remaining liquid baby formula may be preserved safely in a refrigerator for more than 3 h.