Objective: To describe the subgingival microbiome of individuals with Down syndrome (DS). Methods: We conducted a cross-sectional observational study that obtained bacterial DNA samples from 50 patients with DS, 25 with periodontitis (PDS) and 25 with a healthy periodontal condition (HDS). The samples were analyzed by sequencing the 16S rRNA gene V3–V4 hypervariable region using the MiSeq System. Taxonomic affiliations were assigned using the naïve Bayesian classifier integrated in QIIME2 plugins. We evaluated the difference in bacteria abundance between the sample groups using Wilcoxon and Kruskal–Wallis tests. We evaluated the alpha diversity of the identified species using the Observed, Chao1metric, ACE and Shannon indices and evaluated beta diversity with principal coordinate analysis (registration code: 2018/510). Results: Twenty-one genera and 39 bacterial species showed a significantly different abundance between the study groups. Among the genera, Porphyromonas, Treponema, Tannerella and Aggregatibacter were more abundant in the PDS group than in the HDS group, as were the less commonly studied Filifactor, Fretibacterium and Desulfobulbus genera. Among the species, Porphyromonas spp. and Tannerella spp. were the most abundant in the PDS group; the most abundant species in the HDS group were Pseudomonas spp., Granulicatella spp. and Gemella spp. Conclusion: Well-recognized periodontal pathogens and newly proposed pathogenic taxa were associated with periodontitis in patients with DS.

The aim was to study the subgingival microbiota in subjects with Down syndrome (DS) with different periodontal health status, using cultural and molecular microbiological methods. In this cross-sectional study, DS subjects were selected among those attending educational or occupational therapy centers in Galicia (Spain). Medical histories, intraoral and periodontal examinations and microbiological sampling were performed. Samples were processed by means of culture and quantitative polymerase chain reaction (qPCR). Microbiological data were compared, by one-way ANOVA or Kruskal-Wallis and chi-square or Fisher tests, according to their periodontal status. 124 subjects were included, 62 with a healthy periodontium, 34 with gingivitis and 28 with periodontitis. Patients with periodontitis were older (p < 0.01) and showed lower prevalence of hypothyroidism and levothyroxine intake (p = 0.01), presented significantly deeper pockets and more attachment loss (p ≤ 0.01). Both gingivitis and periodontitis subjects showed higher levels of bleeding and dental plaque. PCR counts of T. forsythia and culture counts of E. corrodens and total anaerobic counts were significantly higher in periodontitis patients. Relevant differences were observed in the subgingival microbiota of DS patients with periodontitis, showing higher levels of anaerobic bacteria, T. forsythia and E. corrodens, when compared with periodontally healthy and gingivitis subjects. Moreover, periodontitis subjects were older, had lower frequency of hypothyroidism and higher levels of dental plaque.

The aim of this study was to evaluate the potential anti-biofilm and antibacterial activities of Streptococcus downii sp. nov. To test anti-biofilm properties, Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans were grown in a biofilm model in the presence or not of S. downii sp. nov. for up to 120 h. For the potential antibacterial activity, 24 h-biofilms were exposed to S. downii sp. nov for 24 and 48 h. Biofilms structures and bacterial viability were studied by microscopy, and the effect in bacterial load by quantitative polymerase chain reaction. A generalized linear model was constructed, and results were considered as statistically significant at p < 0.05. The presence of S. downii sp. nov. during biofilm development did not affect the structure of the community, but an anti-biofilm effect against S. mutans was observed (p < 0.001, after 96 and 120 h). For antibacterial activity, after 24 h of exposure to S. downii sp. nov., counts of S. mutans (p = 0.019) and A. actinomycetemcomitans (p = 0.020) were significantly reduced in well-structured biofilms. Although moderate, anti-biofilm and antibacterial activities of S. downii sp. nov. against oral bacteria, including some periodontal pathogens, were demonstrated in an in vitro biofilm model.

A series of new oxovanadium(1V) complexes with benzoic acid hydrazide and p-hydroxybenzoic acid hydrazide have been prepared and characterized. Studies of the chemical and physical properties of these complexes were carried out using I.R. and electronic spectroscopy along with conductivity, magnetic susceptibility and thermogravimetric measurements. It was found that depending on the reaction conditions two types of complexes have been obtained with 1:l and 882 MARTINEZ ET AL.stoichiometry with the general formula being VO(L) X.nH20 (X = SO4' and ZCl-; L = BH and p-HBH) or VOLz, respectively.

The synthesis and characterization of several new oxovanadium (IV) Complexes with acethydrazide (AH) and isonicotinic acid hydrazide (INH) are reported. Elemental analyses, magnetic susceptibility and electrical-conductance measurements, electronic and I.R. spectra and DTA-TGA studies have been used to characterize the compounds. The analytical data and TGA curves show that the 1:l complexes are of the type[ (VO)L]X.nH,O (X=SOi or 2C1-) (L = AH or INH) while the 1:2 complexes are espectral data show that the ligand behaves in the keto or enol form. This depends upon the reaction conditions and the pH of the medium.A square-pyramidal structure is proposed for the compounds on the basis of magnetic and spectral measurements.