Peptostreptococcus micros smooth and rough genotypes in periodontitis and gingivitis

Characterization of the Subgingival Cultivable Microbiota in Patients with Different Stages of Periodontitis in Spain and Colombia. A Cross-Sectional Study

The objective was to characterize and compare the subgingival microbiota in patients diagnosed according to the World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions 2018. For this cross-sectional study, Spanish and Colombian subjects (characterized as health/gingivitis, periodontitis in stages I-II or stages III-IV) were clinically assessed, and subgingival samples were taken and processed by culture. The comparisons among patients with periodontal status (and between countries) was made using Mann–Whitney, Kruskal–Wallis, ANOVA and chi-square tests. The final sample consisted of 167 subjects. Eikenella corrodens and Parvimonas micra were more frequently detected in health/gingivitis and Porphyromonas gingivalis in periodontitis (p < 0.05). Higher total counts were observed in Colombia (p = 0.036). In Spain, significantly higher levels of P. gingivalis and Campylobacter rectus were observed, and of Tannerella forsythia, P. micra, Prevotella intermedia, Fusobacterium nucleatum, Actinomyces odontolyticus and Capnocytophaga spp. in Colombia (p < 0.001). P. micra was more prevalent in health/gingivitis and stage I-II periodontitis in Colombia, and P. gingivalis in all periodontitis groups in Spain (p < 0.05). As conclusions, significant differences were detected in the microbiota between health/gingivitis and periodontitis, with minor differences between stages of periodontitis. Differences were also relevant between countries, with Colombia showing larger counts and variability of bacterial species.

Antibacterial effect of silver diamine fluoride and potassium iodide against E. faecalis, A. naeslundii and P. micra

Background

The aim of this study was to determine in vitro the bactericidal potential of 38% silver diamine fluoride (SDF) alone, potassium iodide (PI) alone, and the two in combination (SDF + PI) against three bacterial species commonly found in root canal samples (Enterococcus faecalis, Actinomyces naeslundii and Parvimonas micra).

Methods

The potential bactericidal rates for SDF, PI and SDF + PI against E. faecalis, A. naeslundii and P. micra were calculated as reduction of bacteria colony forming units.

Results

The bactericidal potential of SDF was at 99.97–100% against E. faecalis and 100% against A. naeslundii and P. micra. SDF + PI showed a 100% bactericidal effect against P. micra, 99.89–99.98% against E. faecalis and 99.98–100% against A. naeslundii. The bactericidal effect of PI was 99.51–99.98% against E. faecalis, 99.27–99.95% against A. naeslundii and 99.93–100% against P. micra. The differences between controls and bacteria exposed to the antibacterial agents were statistically significant (p < 0.05).

Conclusions

SDF had an effective bactericidal effect against the examined bacteria. However, the limitations of this in vitro study do not allow a recommendation of the employment of these solutions as root canal irrigants. Additional investigations are necessary to assess their endodontic clinical applicability.

Composition of microbial oral biofilms during maturation in young healthy adults

In the present study we aimed to analyze the bacterial community structure of oral biofilms at different maturation stages in young healthy adults. Oral biofilms established on membrane filters were collected from 32 human subjects after 5 different maturation intervals (1, 3, 5, 9 and 14 days) and the respective phylogenetic diversity was analyzed by 16S rDNA amplicon sequencing. Our analyses revealed highly diverse entire colonization profiles, spread into 8 phyla/candidate divisions and in 15 different bacterial classes. A large inter-individual difference in the subjects' microbiota was observed, comprising 35% of the total variance, but lacking conspicuous general temporal trends in both alpha and beta diversity. We further obtained strong evidence that subjects can be categorized into three clusters based on three differently occurring and mutually exclusive species clusters.

Etiology and pathogenesis of periodontal diseases

The two most prevalent and most investigated periodontal diseases are dental plaque-induced gingivitis and chronic periodontitis. The last 10 to 15 years have seen the emergence of several important new findings and concepts regarding the etiopathogenesis of periodontal diseases. These findings include the recognition of dental bacterial plaque as a biofilm, identification and characterization of genetic defects that predispose individuals to periodontitis, host-defense mechanisms implicated in periodontal tissue destruction, and the interaction of risk factors with host defenses and bacterial plaque. This article reviews current aspects of the etiology and pathogenesis of periodontal diseases.

Relationship of Subgingival and Salivary Microbiota to Gingival Overgrowth in Heart Transplant Patients Following Cyclosporin A Therapy

BACKGROUND

Severe gingival overgrowth (GO) is induced in patients taking cyclosporin A (CsA) following organ transplantation. Determining which patient will develop GO is still not possible. The purpose of this study was to establish an association between CsA and gingival overgrowth in heart transplant patients taking into account periodontal and microbiological conditions.

METHODS

Thirty patients (10 female, 20 male; range: 13 to 67 years; mean age: 44.89) undergoing CsA treatment were evaluated using the gingival index (GI), plaque index (PI), probing depth (PD), and clinical attachment level (CAL). Subgingival samples collected from the deepest site of each quadrant and saliva samples were submitted to microbial analysis. All patients had at least 12 teeth. Exclusion criteria were the use of antibiotics and/or having undergone periodontal treatment 6 months prior to the study. Patients were divided in two groups: with gingival (GO+) and without gingival overgrowth (GO-).

RESULTS

There were no statistically significant differences between the GO+ and GO- groups when CsA dosage, time since transplant, GI, PI, PD, and CAL were compared. Microbiological examination of the subgingival samples detected the following microorganisms: Actinobacillus actinomycetemcomitans (23%), Porphyromonas gingivalis (36%), Prevotella intermedia (93%), Fusobacterium sp. (66%), Campylobacter rectus (30%), Micromonas micros (66%), enteric rods (0%), and yeasts (30%). A positive association between M. micros and the GO+ group was found (P < 0.001). Yeasts were detected in 30% of the subgingival and saliva samples.

CONCLUSIONS

Clinical parameters were not sufficient to determine which patients would develop GO. However, colonization by M. micros might play a role in the etiology of GO.

Effect of smoking and periodontal treatment on the subgingival microflora

BACKGROUND

The effect of smoking on the prevalence of periodontal pathogens after periodontal treatment is still not clear. Some studies found no effect of the smoking status on the prevalence of periodontal pathogens after therapy, whereas others did. The aim of this retrospective study was to investigate the influence of smoking on the treatment of periodontitis and the composition of the subgingival microflora.

METHOD

The study included 59 periodontitis patients (mean age 41.5 years): 30 smokers and 29 nonsmokers. The treatment consisted of initial periodontal therapy and, if necessary, surgery and/or antibiotics. Clinical and microbiological data were obtained before and after treatment at the deepest site in each quadrant. A pooled sample was analysed for the presence of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotalla intermedia (Pi), Bacteroides forsythus (Bf), Fusobacterium nucleatum (Fn) and Peptostreptococcus micros (Pm).

RESULTS

For smokers and nonsmokers a significant improvement of the clinical condition was found after treatment. A decrease could be assessed for bleeding on probing (smokers: 0.46; nonsmokers: 0.52) and probing pocket depth (PPD) (smokers: 1.64 mm; nonsmokers: 2.09 mm). Furthermore, both groups showed gain of attachment (smokers: 0.68 mm; nonsmokers: 1.46 mm). No significant difference in bleeding on probing and PPD reduction was found between smokers and nonsmokers. In contrast, nonsmokers showed significantly more gain of attachment than smokers. The microbiological results revealed no differences in the prevalence of the various bacteria between smokers and nonsmokers before treatment. After treatment in nonsmokers, a significant decrease was found in the prevalence of Aa (11-3), Pg (17-7), Pi (27-11), Bf (27-11), Fn (28-20) and Pm (27-17). In smokers, a significant decrease could be shown only for the prevalence of Pg (15-5).

CONCLUSIONS

Nonsmokers showed more gain of attachment and a greater decrease in the prevalence of periodontal bacteria as compared to smokers. The phenomenon that among smokers, more patients remain culture positive for periodontal pathogens after therapy, may contribute to the often observed unfavourable treatment results in smoker periodontitis patients.

Molecular analysis of Peptostreptococcus micros isolates from patients with periodontitis

BACKGROUND

Recent studies provide strong evidence implicating Peptostreptococcus micros in the pathogenesis of various oral infections, including oropharyngeal abscesses and periodontal disease. To date, very little is known regarding the role of P. micros in periodontal disease. Therefore, a genetic analysis was initiated to differentiate among strains of P. micros infecting periodontal patients.

METHODS

Sixty DNA samples of P. micros isolated from 15 patients with periodontal disease were evaluated. Arbitrarily primed polymerase chain reactions (AP-PCR) were performed using primer 3 (AGTCAGCCAC) and primer 13 (CAGCACCCAC). The PCR products were analyzed by gel electrophoresis.

RESULTS

The primers produced several unique patterns among the strains tested. Primer 3 resulted in 30 different patterns, whereas primer 13 resulted in 31 different patterns, which were distinct from those seen with primer 3. In 8 of 15 patients, the PCR profile was identical for all isolates cultured from that patient, indicating a clonal infection. In 4 of 15 patients, 2 different genotypes were identified. In the remaining 3 patients, all isolates cultured from these patients exhibited a unique genotype.

CONCLUSIONS

While P. micros appears to be heterogeneous throughout a population of periodontal patients, each patient is, for the most part, infected with a limited number of genotypes. These results demonstrate the genetic diversity of P. micros and the usefulness of AP-PCR for future epidemiological studies in understanding the role P. micros plays in periodontal disease pathogenesis.