ABSTRACT
INTRODUCTION: Candida dubliniensis was reclassified from the C. albicans genotype D, and reports show its frequent detection in HIV-positive individuals and easy acquisition of antifungal drug resistance. However, the oral carriage rate in healthy people and contribution to candidiasis in Japan is unclear. METHODS: We conducted a cross-sectional survey of the C. dubliniensis carriage rate, performed genotyping and tested antifungal drug susceptibility and protease productivity. Specimens from 2432 Japanese subjects in six regions (1902 healthy individuals, 423 with candidiasis individuals, 107 HIV-positive individuals) were cultured using CHROMagarTMCandida, and the species was confirmed via 25S rDNA amplification and ITS sequences analyzed for genotyping. RESULTS: The C. dubliniensis carriage rate in healthy Japanese was low in the central mainland (0-15%) but high in the most northerly and southerly areas (30-40%). The distribution of these frequencies did not differ depending on age or disease (HIV-infection, candidiasis). Genotype I, previously identified in other countries, was most frequent in Japan, but novel genotypes were also observed. Six antifungal drugs showed higher susceptibility against C. albicans, but protease productivity was low. CONCLUSIONS: Oral C. dubliniensis has low pathogenicity with distribution properties attributed to geography and not dependent on age or disease status.
ABSTRACT
Introduction Early life stress (ELS) caused by abuse and bullying has increased dramatically, however, effective means for accurate detection have not been found. Some decades ago, an association between stress and dental caries was suggested. However, even now, stress is not recognized widely as a potential risk factor for caries. Therefore, the purpose of this study was to verify the possible effects of stress by comparing them to the effects of saliva factors and the microorganisms that pose a general caries risk. Methods We conducted cross-sectional observation research on 30 children with mental problems, diagnosed as 'stressed,' and 30 age-matched unstressed children in the same elementary school. An oral examination (dental caries diagnosis) and an oral environment survey (saliva test) were carried out in 2007. Further, the concentration and activity of salivary stress proteins were measured. All variables were statistically analyzed using the Mann-Whitney U test, correlation, and multivariate analysis. Results The dental caries experience ratio was significantly higher in the stress group, and only the concentration of CgA, a salivary stress protein, showed a significant difference. Unexpectedly, we did not detect any differences in the rates and counts of cariogenic bacteria or salivary buffering activity. Binomial logistic regression analysis only showed significance in the presence or absence of ELS. Conclusion Stress factors may have a stronger influence on caries development in the stress group than in the general caries risk. Therefore, long-term stress, causing changes in the children's bodies, might hint at important factors leading to the development of dental caries.
ABSTRACT
OBJECTIVES: Plaque causes oral diseases and aspiration-pneumonia in the elderly. It is not known whether pellicle-like attached salivary proteins and microbiota on dental materials are identical to those on teeth. The purpose of this study was to determine the properties of salivary proteins and microbiota that attach to dental materials. METHODS: Eight subjects wore removable oral splints with pieces of pure-titanium, cobalt-chromium alloy, silver-palladium-copper-gold-alloy, denture-base-resin, and hydroxyapatite for 24 h. The bacteria that adhered to each material were analyzed using 16S rRNA sequencing simultaneously. Each material sample was then immersed in pooled saliva, and the attached proteins were collected. Salivary proteins were analyzed using MALDI-TOF/MS, and high molecular weight proteins were identified using peptide mass fingerprinting. RESULTS: Among the dental materials, the α- and ß-diversity of adherent flora were similar. The bacterial species that adhered easily to materials were Streptococcus sp. oral taxon 058, Neisseria mucosa, Gemella haemolysans, and Rothia dentocariosa. Regardless of material, the peaks or spots of attached salivary proteins had similar patterns, containing functioning proteins such as anchoring receptors for early colonizers. CONCLUSIONS: There were no significant differences in microbiota and protein adherence in hydroxyapatite compared to the dental materials. Therefore, similar microbiota was determined to have formed on the similar pellicle-like proteins. In our study, the characteristics of plaque adhesion on both hydroxyapatite and dental materials were clarified. Based on this study, the creation of new methods of inhibiting plaque adhesion to prevent aspiration-pneumonia and oral infections can be undertaken.
