Smoking habit modulates peri-implant microbiome: A case-control study.

BACKGROUND AND OBJECTIVE: Smoking is a recognized risk factor for peri-implant disease and leads to microbiological changes in mucositis and peri-implantitis. However, there is no knowledge about the impact of smoking in healthy peri-implant tissue. The aim of the study was to evaluate the microbiome in a peri-implant environment in smokers with healthy peri-implant conditions. METHODS: Peri-implant biofilm was collected around single clinically healthy, screwed-retained, teeth-surrounded implants in 12 non-smoker (NSMK) and 12 smoker (SMK) non-periodontitis subjects (no bleeding and probing depth <4 mm). Bacterial DNA was isolated and 16S ribosomal RNA gene libraries were sequenced using pyrosequencing, targeting the V3-V4 region. Datasets were processed using the Quantitative Insights into Microbial Ecology, Greengenes and the Human Oral Microbiome Database databases. RESULTS: An evident difference in the SMK peri-implant microbiome was observed compared to the NSMK microbiome, with a large abundance of species, even with a healthy peri-implant. The SMK core-microbiome showed an abundance of Fusobacterium, Tannerella and Mogibacterium, while the NSMK core revealed an abundance of Actinomyces, Capnocytophaga and Streptococcus, genera that are usually related to periodontal health. The microbiome inter-relationship was shown to be more inter-generic in SMK then in NSMK, indicating different microbiome cohesion. CONCLUSION: Smoking negatively affected the peri-implant microbiome, leading to a disease-associated state, even in clinically healthy individuals.

Evaluation of oral microbiota in undernourished and eutrophic children using checkerboard DNA-DNA hybridization.

The aim of this study was to evaluate the relationship among nutritional status, gingival health and the composition of oral microbiota in children of a public school from a very poor area of San Miguel de Tucuman. Forty-five children ranging in age from 6 to 14 years old, 13 males and 32 females were studied. Twenty of these children were undernourished (Lejarraga-Morasso Table) and twenty-five were eutrophic. A clinical study that included DMF and dmf indexes, Löe Silness Plaque Index and bleeding on probing was performed. For microbiological study, saliva samples without stimulation were taken; aliquots of them were immediately placed in TAE buffer pH 7.6, adding NaOH (N and keeping at -70 °C until processed by checkerboard DNA-DNA hybridization method to check the presence of 40 oral microorganism species. Positive bleeding on probing was present in more than 80% of children, without significant differences between eutrophic and undernourished groups. Same result were obtain for the other clinical indexes (p > 0.05, Two Way ANOVA). Significant differences were found for some oral microorganism species, with a higher percentage of undernourished children harboring them. That was the case of S. gordonii (p < 0.05), Capnocitophaga gingivalis and C. ochraceae (p < 0.01 and p < 0.10, respectively), F. nucleatum ss nucleatum (p < 0.05), P. nigrescens (p < 0.10), Campylobacter gracilis (p < 0,05), and T. denticola (p < 0.10, multiple logistic regression). Significant differences were also found between children groups for E. saborreum (p < 0.001), P. acnes (p < 0.10), G. morbillorum (p < 0.05) and L. buccalis (p < 0.10). Gingivitis and bleeding on probing would not be related to nutritional status in the groups of children studied. There were significant differences for the presence of some of the main periodontal pathogen species between eutrophic and undernourished children. It would be important to study the meaning of significant differences found for the other microorganisms more deeply.

[Fatal bacteremia related to Capnocytophaga sputigena in a hematological patient with type T non-Hodgkin lymphoma. Diagnosis by 16S rRNA gene sequencing]. / Bacteriemia fulminante asociada a Capnocytophaga sputigena en un paciente con linfoma no Hodgkin tipo T. Diagnóstico por secuenciación genética del ARNr 16S.

We described a case of fatal bacteremia related to Capnocytophaga sputigena in a hematological patient. The strain was identified by 16S rRNA gene sequencing.

In vitro evaluation of bacterial leakage along the implant-abutment interface of an external-hex implant after saliva incubation.

The aim of this in vitro study was to evaluate bacterial leakage along the implant-abutment interface under unloaded conditions. Twelve premachined abutments with plastic sleeves and 12 dental implants were used in this study. Prior to tests of bacterial leakage, samples from the inner parts of the implants were collected with sterile microbrushes to serve as negative controls for contamination. After casting, the abutments were tightened to 32 Ncm on the implants. The assemblies were immersed in 2.0 mL of human saliva and incubated for 7 days. After this period, possible contamination of the internal parts of the implants was evaluated using the DNA Checkerboard method. Microorganisms were found in the internal surfaces of all the implants evaluated. Aggregatibacter actinomycetemcomitans and Capnocytophaga gingivalis were the most incident species. No microorganisms were found in the samples recovered from the implants before contamination testing (negative control). Bacterial species from human saliva may penetrate the implant-abutment interface under unloaded conditions.