Development of 16S rDNA-based PCR assay for detecting centipeda periodontii and selenomonas sputigena

Detection and comparison of Selenomonas sputigena in subgingival biofilms in chronic and aggressive periodontitis patients

Background:

With the advent of DNA-based culture-independent techniques, a constantly growing number of Selenomonas phylotypes have been detected in patients with destructive periodontal diseases. However, the prevalence levels that have been determined in different studies vary considerably.

Aim:

The present study was undertaken to detect and compare the presence of Selenomonas sputigena in the subgingival plaque samples from generalized aggressive periodontitis (GAP), chronic generalized periodontitis, and periodontally healthy patients using conventional polymerase chain reaction (PCR) technique.

Materials and Methods:

A total of 90 patients were categorized as periodontally healthy individuals (Group I, n = 30), chronic generalized periodontitis (Group II, n = 30), and GAP (Group III, n = 30). The clinical parameters were recorded and subgingival plaque samples were collected. These were then subjected to conventional PCR analysis.

Statistical Analysis Used:

Kruskal–Wallis ANOVA test was used for multiple group comparisons followed by Mann–Whitney U-test for pairwise comparison.

Results:

On comparison between three groups, all the clinical parameters were found to be statistically highly significant. Comparing Groups I-II and I-III, the difference in detection was found to be statistically highly significant whereas in Groups II-III, it was statistically nonsignificant. On comparison of S. sputigena detected and undetected patients to clinical parameters in various study groups, the difference was found to be nonsignificant.

Conclusion:

S. sputigena was found to be significantly associated with chronic and aggressive periodontitis. Although the difference in its detection frequency in both groups was statistically nonsignificant when compared clinically, S. sputigena was more closely associated with the GAP.

Quantification of Selenomonas sputigena in Chronic Periodontitis in Smokers Using 16S rDNA Based PCR Analysis

BACKGROUND AND AIM

Selenomonas species have been associated with chronic periodontitis and have been implicated in converting periodontal health to disease. Scanty literature is available in Indian population. Hence, the objective of the study was to detect the prevalence of Selenomonas sputigena in healthy and chronic periodontitis by polymerase chain reaction (PCR) in Indian population and to check whether smoking affects the subgingival microflora of this organism in chronic periodontitis.

MATERIALS AND METHODS

A total of 60 subjects with severe chronic periodontitis with or without smoking and periodontal healthy subjects underwent clinical and microbiological assessment. A deep subgingival plaque sample was collected and genomic DNA was extracted from each sample and analysed for detection of Selnomonas sputigena using PCR. The frequency and quantification of bacteria were also estimated.

RESULTS

All groups differed statistically significant in the frequency of detection of Selenomonas sputigena. On comparison of patients with chronic periodontitis in smokers and non-smokers, there was no statistically significant difference. When the results were quantified, statistically non-significant results were seen among all groups. Plaque index, gingival index, probing pocket depth and clinical attachment level were statistically non-significant in chronic periodontitis with smokers and non-smokers.

CONCLUSION

Prevalence of Selenomonas sputigena showed significant differences with respect to the frequency of detection when comparing the disease group to the healthy population. But no significant difference was seen when the results were quantified. Smoking has no influence on number of Selenomonas sputigena. This study highlights presence as well as quantity of the organism is very important in elucidating its role in causation and progression of the disease.

Newly identified pathogens associated with periodontitis: a systematic review

There is substantial evidence supporting the role of certain oral bacteria species in the onset and progression of periodontitis. Nevertheless, results of independent-culture diagnostic methods introduced about a decade ago have pointed to the existence of new periodontal pathogens. However, the data of these studies have not been evaluated together, which may generate some misunderstanding on the actual role of these microorganisms in the etiology of periodontitis. The aim of this systematic review was to determine the current weight of evidence for newly identified periodontal pathogens based on the results of "association" studies. This review was conducted and reported in accordance with the PRISMA statement. The MEDLINE, EMBASE, and Cochrane databases were searched up to September 2013 for studies (1) comparing microbial data of subgingival plaque samples collected from subjects with periodontitis and periodontal health and (2) evaluating at least 1 microorganism other than the already-known periodontal pathogens. From 1,450 papers identified, 41 studies were eligible. The data were extracted and registered in predefined piloted forms. The results suggested that there is moderate evidence in the literature to support the association of 17 species or phylotypes from the phyla Bacteroidetes, Candidatus Saccharibacteria, Firmicutes, Proteobacteria, Spirochaetes, and Synergistetes. The phylum Candidatus Saccharibacteria and the Archaea domain also seem to have an association with disease. These data point out the importance of previously unidentified species in the etiology of periodontitis and might guide future investigations on the actual role of these suspected new pathogens in the onset and progression of this infection.

Centipeda periodontii in human periodontitis

This study assessed the subgingival occurrence of the flagellated, Gram-negative, anaerobic rod Centipeda periodontii in chronic periodontitis and periodontal health/gingivitis with species-specific nucleic acid probes, and evaluated the in vitro resistance of subgingival isolates to therapeutic levels of amoxicillin, metronidazole, and doxycycline. Subgingival plaque biofilm specimens from 307 adults with chronic periodontitis, and 48 adults with periodontal health/localized gingivitis, were evaluated with digoxigenin-labeled, whole-chromosomal, DNA probes to C. periodontii ATCC 35019 possessing a 10(4) cell detection threshold. Fifty-two C. periodontii subgingival culture isolates were assessed on antibiotic-supplemented enriched Brucella blood agar for in vitro resistance to either amoxicillin at 2 µg/ml, metronidazole at 4 µg/ml, or doxycycline at 2 µg/ml. A significantly greater subgingival occurrence of C. periodontii was found in chronic periodontitis subjects as compared to individuals with periodontal health/gingivitis (13.4 vs. 0 %, P < 0.003), although high subgingival counts of the organism (≥ 10(6) cells) were rarely detected (1.3 % of chronic periodontitis subjects). In vitro resistance was not found to amoxicillin or metronidazole, and to doxycycline in only 2 (3.9 %) of the 52 C. periodontii clinical isolates studied. These findings indicate that C. periodontii is not a major constituent of the subgingival microbiome in chronic periodontitis or periodontal health/gingivitis. The potential contribution of C. periodontii to periodontal breakdown in the few chronic periodontitis subjects who yielded high subgingival levels of the organism remains to be delineated. C. periodontii clinical isolates were susceptible in vitro to therapeutic concentrations of three antibiotics frequently used in treatment of human periodontitis.

Subgingival microbiota from Cebus apella (capuchin monkey) with different periodontal conditions

This present study evaluated the subgingival microbiota of the Cebus apella with different periodontal conditions kept by the Tufted Capuchin Monkey Procreation Center (São Paulo State University - UNESP) or free-ranging monkeys. For this purpose, clinical specimens of subgingival biofilm were collected from 52 monkeys, of both genders, 40 kept in captivity and 12 free-ranging monkeys. The primates were submitted to periodontal evaluation and biofilm samples were transferred to VMGA III transport medium and ultrapure water. The microbiota was cultivated in selective and non-selective culture media and microbial DNA was extracted and the presence of periodontal pathogens was evaluated using PCR and real-time PCR. The actinomycetes, fusobacteria, Campylobacter rectus, Eikenella corrodens, black-pigmented Gram-negative anaerobic rods, Tannerella forsythia, staphylococci and streptococci represent the predominantly detected microorganisms. Aggregatibacter actinomycetemcomitans, Dialister pneumosintes and Prevotella nigrescens were rarely observed, whereas Treponema denticola was not found. Populations of C. rectus, E. corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, T. forsythia and the total microbial load were significantly higher in animals with bone loss and, in smaller extension, in animals with gingival bleeding.

A new checkerboard panel for testing bacterial markers in periodontal disease

BACKGROUND/AIMS

Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens ('old panel') using the 'checkerboard' DNA-DNA hybridization method.

METHODS

Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin-labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species.

RESULTS

Twenty-four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 10(4)) and score 3 (> 10(5)). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites.

CONCLUSION

It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis-associated bacterial flora.

Detection frequency of periodontitis-associated bacteria by polymerase chain reaction in subgingival and supragingival plaque of periodontitis and healthy subjects

The aim of this study was to compare the detection frequencies of 25 bacterial species in subgingival and supragingival plaque of 18 untreated periodontitis subjects and 12 periodontally healthy subjects. Genomic DNA was extracted from subgingival and supragingival plaque samples, and bacterial detection was performed by polymerase chain reaction of the 16S rRNA genes. Fourteen bacteria showed no relationship with periodontitis, and 11 of these 14 species were frequently detected (> or =50%) in subgingival plaque in both periodontitis and healthy subjects. Nine bacteria such as Eubacterium saphenum, Prevotella intermedia, and Treponema denticola seemed to be related to periodontitis; their detection frequencies in subgingival plaque samples were higher in periodontitis than in healthy subjects, but these differences were not statistically significant by multiple comparisons (0.002< or =P<0.05). Two species (Mogibacterium timidum and Porphyromonas gingivalis) were detected significantly more frequently in subgingival plaque of periodontitis subjects than of healthy subjects (P<0.002), with P. gingivalis being detected only in periodontitis subjects, suggesting that these two species are closely related to periodontitis. There were no significant differences in the detection frequencies of the 25 bacteria between subgingival and supragingival plaque, suggesting that the bacterial flora of supragingival plaque reflects that of subgingival plaque.

Nested PCR detection of Centipeda periodontii in primary endodontic infections

In recent years, molecular genetic methodologies have provided significant additional knowledge about components of the microbiota associated with infections of endodontic origin. Following this research line, the purpose of the present study was to investigate the prevalence of Centipeda periodontii in primary endodontic infections using a species-specific nested PCR assay. Samples were collected from fifty teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, and a second round of amplification used the first PCR products to detect a specific fragment of C. periodontii 16S rDNA. This species was detected in 3 (13%) of 23 asymptomatic cases, in 1 (14%) of 7 cases diagnosed as acute apical periodontitis, and in 3 (15%) of 20 pus samples aspirated from acute periradicular abscesses. There was no significant association between C. periodontii and the presence of clinical symptoms. Overall, C. periodontii was detected in 14% of the cases of endodontic infections. This is probably the hitherto first study to detect C. periodontii in primary endodontic infections. The specific role played by this bacterial species in infections of endodontic origin awaits further clarification.