RESUMO
Streptococcus dentisani has been proposed as a promising probiotic against tooth decay, due to its ability to buffer acidic pH and to inhibit the growth of oral pathogens. However, it is unknown if this bacterial species has a global distribution. The current study aimed to establish the presence of S. dentisani in oral samples from different geographic locations by identifying the sequence of its 16S rRNA gene in available datasets from across the globe. In addition, an analytical and cross-sectional study was carried out to determine if the levels of this probiotic strain are higher in caries-free individuals compared to those with dental caries. Samples from various geographical sources demonstrated that S. dentisani is present in saliva and dental plaque from individuals of different continents. Typical S. dentisani levels in saliva ranged from 104 to 105 cells/ml and a total of 106-107 cells in dental plaque. Using real-time qPCR, S. dentisani was quantified from supragingival dental plaque of 25 caries-free and 29 caries-active individuals from a Mexican children population, where significantly higher proportions of S. dentisani were found in the caries-free group (p = 0.002). Finally, a negative correlation was found between caries levels (as measured by the dmft caries index) and the percentage of S. dentisani (p < 0.001). Thus, the current manuscript indicates that this species has a global distribution, can be found in saliva and dental plaque, and appears to be present in higher numbers in plaque samples from caries-free children.
Assuntos
Cárie Dentária , Microbiota , Estudos Transversais , Cárie Dentária/epidemiologia , Humanos , RNA Ribossômico 16S/genética , StreptococcusRESUMO
Streptococcus dentisani has been identified as an oral cavity probiotic due to its beneficial characteristics. One of its beneficial features is the production of bacteriocins, which inhibit the growth of cariogenic bacteria, and another is its buffering capacity through the production of ammonium from arginine. The purpose of this study was to determine the presence of S. dentisani in the dental plaque of Colombian children and whether the presence of this bacterium is related to oral health and other conditions. Dental plaque and information on diet and oral hygiene habits were collected from children between 6 and 12 years of age from four Colombian cities, divided into caries-free children (International Caries Detection and Assessment System [ICDAS] 0, Decayed Missing Filled Teeth index [DMFT] 0), children with ICDAS 1 and 2, and children with ICDAS >3. Plaque DNA was extracted and quantified, and real-time polymerase chain reaction was performed using specific primers. This bacterium was identified in all samples, with a median of 0.46 cells/ng DNA (interquartile range [IQR] 0.13-1.02), without finding significant differences between the groups (P > 0.05). In caries-free children, a median of 0.45 cells/ng DNA (IQR 0.14-1.23) was found. In children with ICDAS 1 and 2, the median was 0.49 cells/ng DNA (IQR 0.11-0.97), and in children with ICDAS >3, the median was 0.35 cells/ng DNA (IQR 0.12-1.07). However, statistically significant differences were found in the origin of children (P < 0.01), the use of fluoride-containing products (P < 0.01), and the frequency of food intake (P < 0.05). In conclusion, the presence of S. dentisani was quantified in children from four Colombian cities, without finding significant differences in oral health status. Nevertheless, three conditions showed a possible relationship with S. dentisani.
Assuntos
Cárie Dentária/microbiologia , Placa Dentária/microbiologia , Streptococcus/isolamento & purificação , Estudos de Casos e Controles , Criança , Cidades , Colômbia , Índice CPO , DNA Bacteriano/análise , Feminino , Humanos , Masculino , Microbiota , Saúde Bucal , Fatores de Proteção , Fatores de Risco , Streptococcus/genéticaRESUMO
A Gram-negative, arsenite-oxidizing bacterial strain, designated VC-1, was isolated from sediment samples from the Camarones Valley in the Atacama Desert, Chile. Strain VC-1 was strictly aerobic, oxidase and catalase positive, rod shaped, of about 5.5 microm in length and 0.5-1.0 microm in diameter. It was motile by means of multiple polar flagella. The phylogenetic reconstruction of the 16S rRNA gene sequence, an MLSA study by concatenating six genes, and DDH studies indicated that the strain differed genotypically from its closest relatives and was therefore recognized as a new species within the genus Pseudomonas. Phenotypic analysis combining metabolic tests, fatty acid profiles and MALDI-TOF profiles of total cell extracts supported the classification of the new species for which we propose the designation Pseudomonas arsenicoxydans sp. nov. The type strain is accessible under the culture collection numbers CCUG 58201(T) and CECT 7543(T).
Assuntos
Arsenitos/metabolismo , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , Microbiologia do Solo , Aerobiose , Proteínas de Bactérias/metabolismo , Técnicas de Tipagem Bacteriana , Catalase/metabolismo , Chile , Análise por Conglomerados , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Flagelos/fisiologia , Locomoção , Dados de Sequência Molecular , Oxirredução , Oxirredutases/metabolismo , Filogenia , Pseudomonas/genética , Pseudomonas/fisiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Bioremediation is an important technology for the removal of persistent organic pollutants from the environment. Bioaugmentation with the encapsulated Pseudomonas sp. strain MHP41 of agricultural soils contaminated with the herbicide simazine was studied. The experiments were performed in microcosm trials using two soils: soil that had never been previously exposed to s-triazines (NS) and soil that had >20 years of s-triazine application (AS). The efficiency of the bioremediation process was assessed by monitoring simazine removal by HPLC. The simazine-degrading microbiota was estimated using an indicator for respiration combined with most-probable-number enumeration. The soil bacterial community structures and the effect of bioaugmentation on these communities were determined using 16S RNA gene clone libraries and FISH analysis. Bioaugmentation with MHP41 cells enhanced simazine degradation and increased the number of simazine-degrading microorganisms in the two soils. In highly contaminated NS soil, bioaugmentation with strain MHP41 was essential for simazine removal. Comparative analysis of 16S rRNA gene clone libraries from NS and AS soils revealed high bacterial diversity. Bioaugmentation with strain MHP41 promoted soil bacterial community shifts. FISH analysis revealed that bioaugmentation increased the relative abundances of two phylogenetic groups (Acidobacteria and Planctomycetes) in both soils. Although members of the Archaea were metabolically active in these soils, their relative abundance was not altered by bioaugmentation.