Rapid identification of important periodontal microorganisms by cultivation

Aggressive periodontitis in southwestern American Indian adolescents

BACKGROUND

This study determined the prevalence of aggressive (molar-incisor pattern) (Ag/MI) periodontitis and assessed the associated subgingival bacterial-herpesvirus microbiota in Pueblo Indian adolescents in the southwestern United States.

METHODS

The study included 240 Pueblo Indian adolescents, aged 13-20 years old, residing in three Rio Grande River villages in New Mexico and the Hopi Pueblo reservation in Arizona. Adolescents with Ag/MI periodontitis or periodontal health provided subgingival samples for culture of bacterial pathogens and for polymerase chain reaction detection of periodontal herpesviruses.

RESULTS

Ag/MI periodontitis was detected in 22 (9.2%) Pueblo Indian adolescents, with 21 exhibiting a localized molar-incisor breakdown pattern. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and other red/orange complex bacterial pathogens predominated in Ag/MI periodontitis, whereas periodontal health yielded mainly viridans streptococci and Actinomyces species. Periodontal herpesviruses demonstrated a 3.5 odds ratio relationship with Ag/MI periodontitis. The only adolescent with generalized Ag/MI periodontitis harbored viral co-infection by cytomegalovirus plus Epstein-Barr virus Type 1, in addition to A. actinomycetemcomitans, P. gingivalis, and several other periodontopathic bacteria.

CONCLUSIONS

Pueblo Indian adolescents showed an unusually high prevalence of early-age Ag/MI periodontitis predominated by periodontopathic bacteria and herpesviruses suspected to be major etiologic agents of the disease.

Antimicrobial Chemotherapy for Recalcitrant Severe Human Periodontitis

This study evaluated a combined systemic and topical anti-infective periodontal treatment of 35 adults who had experienced ongoing periodontal breakdown following conventional surgical periodontics. The prescribed anti-infective therapy, based on microbiological testing, consisted of a single course of metronidazole plus ciprofloxacin (23 patients), metronidazole plus amoxicillin/clavulanic acid (10 patients), and metronidazole plus ciprofloxacin followed by metronidazole plus amoxicillin/clavulanic acid (2 patients). In addition, the study patients received 0.1% povidone-iodine subgingival disinfection during non-surgical root debridement and daily patient administered oral irrigation with 0.1% sodium hypochlorite. At 1 and 5 years post-treatment, all study patients showed gains in clinical periodontal attachment with no further attachment loss, and significant decreases in pocket probing depth, bleeding on probing, and subgingival temperature. The greatest disease resolution occurred in patients who at baseline harbored predominantly major periodontal pathogens which post-antibiotics became non-detectable and substituted by non-periodontopathic viridans streptococci. The personalized and minimally invasive anti-infective treatment regimen described here controlled periodontitis disease activity and markedly improved the clinical and microbiological status of the refractory periodontitis patients.

A critical analysis of research methods and experimental models to study the root canal microbiome

Endodontic microbiology deals with the study of the microbial aetiology and pathogenesis of pulpal and periradicular inflammatory diseases. Research in endodontic microbiology started almost 130 years ago and since then has mostly focussed on establishing and confirming the infectious aetiology of apical periodontitis, identifying the microbial species associated with the different types of endodontic infections and determining the efficacy of treatment procedures in eradicating or controlling infection. Diverse analytical methods have been used over the years, each one with their own advantages and limitations. In this review, the main features and applications of the most used technologies are discussed, and advice is provided to improve study designs in order to properly address the scientific questions and avoid setbacks that can compromise the results. Finally, areas of future research are described.

Oral microbiota-induced periodontitis: a new risk factor of metabolic diseases

It has recently become evident that the periodontium (gingiva, desmodontal ligament, cementum and alveolar bone) and the associated microbiota play a pivotal role in regulating human health and diseases. The oral cavity is the second largest microbiota in the body with around 500 different bacterial species identified today. When disruption of oral cavity and dysbiosis occur, the proportion of strict anaerobic Gram-negative bacteria is then increased. Patients with periodontitis present 27 to 53% more risk to develop diabetes than the control population suggesting that periodontitis is an aggravating factor in the incidence of diabetes. Moreover, dysbiosis of oral microbiota is involved in both periodontal and metabolic disorders (cardiovascular diseases, dyslipidaemia …). The oral diabetic dysbiosis is characterized by a specific bacteria Porphyromonas, which is highly expressed in periodontal diseases and could exacerbate insulin resistance. In this review, we will address the nature of the oral microbiota and how it affects systemic pathologies with a bidirectional interaction. We also propose that using prebiotics like Akkermansia muciniphila may influence oral microbiota as novel therapeutic strategies. The discovery of the implication of oral microbiota for the control of metabolic diseases could be a new way for personalized medicine.

Phenotypic identification of periodontal Prevotella intermedia/nigrescens group isolates validated by MALDI-TOF mass spectrometry

The accuracy of a phenotypic scheme to recognize periodontal Prevotella intermedia/nigrescens group clinical isolates on primary isolation culture plates was assessed with matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 84 fresh subgingival isolates from 23 chronic periodontitis patients were presumptively recognized on anaerobically-incubated enriched Brucella blood agar primary isolation plates as P. intermedia/nigrescens based on their dark-pigmented colony morphology, brick-red autofluorescence under long-wave ultraviolet light, and a negative fluorescence test for lactose production. The presumptive P. intermedia/nigrescens clinical isolates were subjected to MALDI-TOF MS analysis using Bruker MALDI Biotyper analytic software containing mass spectra for P. intermedia and Prevotella nigrescens in its reference library of bacterial protein profiles. Using a ≥1.7 log score agreement threshold, 60 (71.4%) of the presumptive P. intermedia/nigrescens clinical isolates were confirmed as either P. intermedia (25 isolates) or P. nigrescens (35 isolates). All isolates with a <1.7 log score were also identified as P. intermedia or P. nigrescens from the top choice designated on the MALDI Biotyper most likely species identification list. These MALDI-TOF MS findings document the ability of the phenotypic scheme to correctly recognize most periodontal P. intermedia/nigrescens group clinical isolates on primary isolation culture plates.

A Comparative Study: Taxonomic Grouping of Alkaline Protease Producing Bacilli

Alkaline proteases have biotechnological importance due to their activity and stability at alkaline pH. 56 bacteria, capable of growing under alkaline conditions were isolated and their alkaline protease activities were carried out at different parameters to determine their optimum alkaline protease production conditions. Seven isolates were showed higher alkaline protease production capacity than the reference strains. The highest alkaline protease producing isolates (103125 U/g), E114 and C265, were identified as Bacillus licheniformis with 99.4% and Bacillus mojavensis 99.8% based on 16S rRNA gene sequence similarities, respectively. Interestingly, the isolates identified as Bacillus safensis were also found to be high alkaline protease producing strains. Genotypic characterizations of the isolates were also determined by using a wide range of molecular techniques (ARDRA, ITS-PCR, (GTG)5-PCR, BOX-PCR). These different techniques allowed us to differentiate the alkaliphilic isolates and the results were in concurrence with phylogenetic analyses of the 16S rRNA genes. While ITS-PCR provided the highest correlation with 16S rRNA groups, (GTG)5-PCR showed the highest differentiation at species and intra-species level. In this study, each of the biotechnologically valuable alkaline protease producing isolates was grouped into their taxonomic positions with multi-genotypic analyses.

An innate immune system-mimicking, real-time biosensing of infectious bacteria

An immune system-mimicking real-time biosensing could detect bacteria (<100 CFU mL⁻¹) automatically within the working time.

Evaluation of a new oral health scale of infectious potential based on the salivary microbiota

OBJECTIVES

The objective of this study is to analyse the correlation of our own design of oral health scale (grades 0 and 1-better oral health vs. grades 2 and 3-poorer oral health) with the salivary microbiota.

PATIENTS AND METHODS

The oral health scale we elaborated was evaluated in 100 adults (25 patients from each global oral health grade). Saliva samples collected from these patients were analysed using microbiological culture techniques, determining the presence/absence and the concentrations of some odontopathogens and periodontopathogens.

RESULTS

In comparison with the global oral health grades 0-1, the grades 2-3 presented significantly higher values for the presence of odontopathogens (78 vs. 38 %; Streptococcus mutans, Lactobacillus spp. and Actinomyces spp.) and periodontopathogens (100 vs. 90 %; Aggregatibacter actinomycetemcomitans, Campylobacter spp., Fusobacterium spp. and Prevotella gingivalis). In comparison with the grades 0-1, the grades 2-3 presented significantly higher values for the concentrations (CFU/mL log10) of facultative anaerobes, strict anaerobes, odontopathogens (S. mutans, Lactobacillus spp. and Actinomyces spp.) and periodontopathogens (A. actinomycetemcomitans, Capnocytophaga spp., Campylobacter spp. and Fusobacterium spp.).

CONCLUSION

Our new global oral health scale shows a positive correlation with the detection and quantification of certain odontopathogens and periodontopathogens present in the saliva, confirming their possible infectious potential.

CLINICAL RELEVANCE

Our own design of oral health scale could be particularly useful for the epidemiological study of different populations, the evaluation of the influence of oral health on the development of certain systemic diseases as well as the analysis of inter- and intra-individual variability of the oral microbiota in relation to the different grades of the oral health scale.

Investigation of the oral infections and manifestations seen in patients with advanced cancer

Objective: A prospective, observational study was undertaken to investigate the epidemiology of oral infection among the patients with advanced malignancies, and to investigate the effects of therapy strategies and risk factors on the incidence of oral infection.

Methods: The patients with advanced malignancies were enrolled into the study. The incidence of oral infection with different malignant tumor groups or different treatment methods and the diagnoses of oral infection were confirmed. Demographic data on age, gender, bed rest time, nutritional status, smoking habit and the presence of oral prosthesis were also recorded.

Results: Oral infection was prevalent in 46% (391/850) of all cancer patients, with the highest rate in oral and maxillofacial cancer group (67%), followed by Hematological malignancy group (58.6%) and other groups (ranging from 43.3% to 35.3%). Oral candidiasis, oral herpes simplex, and oral mucositis were the popular infectious diseases in the patients. Chemotherapy and radiotherapy, especially combined radio- and chemotherapy, resulted in more oral infections compared with palliative care and surgery. Poor nutritional status and oral prosthesis were identified as independent risk factors associated with oral infection.

Conclusion: Oral infection is prevalent among advanced cancer patients and associated with therapy methods and risk factors. More oral health care should be carried out for the patients with advanced malignant tumor.

Microbiological Aspects of Human Mandibular Subperiosteal Dental Implants

Clinical, microbiological, and biochemical features of human mandibular subperiosteal dental implants exhibiting peri-implantitis were compared with those experiencing long-term peri-implant health. After evaluation of clinical parameters, submucosal plaque samples were obtained from permucosal implant abutment posts exhibiting probing depths ≥5 mm and bleeding on probing in subjects with peri-implantitis (n = 3) and from posts with peri-implant health in subjects with long-term subperiosteal implant health (n = 8). The microbial specimens were transported in VMGA III and plated onto enriched Brucella blood agar and Hammond's selective medium with anaerobic incubation, and onto selective TSBV with 5% CO2 incubation. Total anaerobic viable counts and selected bacterial species were identified using established phenotypic methods and criteria. In vitro resistance to doxycycline (2 μg/mL), amoxicillin (2 μg/mL), or metronidazole (4 μg/mL) was recorded per subject when bacterial pathogen growth was noted on antibiotic-supplemented isolation plates. Interleukin (IL)–1β levels were measured with an enzyme-linked immunosorbent assay in peri-implant crevicular fluid samples from 5 study subjects. Significantly higher Plaque Index scores, higher total anaerobic viable counts, more red complex species, and lower proportions of gram-positive facultative viridans streptococci and Actinomyces species were detected on peri-implantitis–affected subperiosteal implants as compared with subperiosteal implants with long-term peri-implant health. No in vitro resistance to the 3 test antibiotic breakpoint concentrations studied was found, except a Fusobacterium nucleatum strain resistant to doxycycline at 2 μg/mL from 1 peri-implantitis subject. Subperiosteal implants with peri-implantitis tended to yield higher peri-implant crevicular fluid IL-1β levels. The level of peri-implant supramucosal plaque control and the composition of the peri-implant submucosal microbiome may be important determinants of the long-term clinical status of mandibular subperiosteal dental implants.

Antibiotic resistance in human peri-implantitis microbiota

OBJECTIVES

Because antimicrobial therapy is often employed in the treatment of infectious dental implant complications, this study determined the occurrence of in vitro antibiotic resistance among putative peri-implantitis bacterial pathogens.

METHODS

Submucosal biofilm specimens were cultured from 160 dental implants with peri-implantitis in 120 adults, with isolated putative pathogens identified to species level, and tested in vitro for susceptibility to 4 mg/l of doxycycline, 8 mg/l of amoxicillin, 16 mg/l of metronidazole, and 4 mg/l of clindamycin. Findings for amoxicillin and metronidazole were combined post-hoc to identify peri-implantitis species resistant to both antibiotics. Gram-negative enteric rods/pseudomonads were subjected to ciprofloxacin disk diffusion testing.

RESULTS

One or more cultivable submucosal bacterial pathogens, most often Prevotella intermedia/nigrescens or Streptococcus constellatus, were resistant in vitro to clindamycin, amoxicillin, doxycycline, or metronidazole in 46.7%, 39.2%, 25%, and 21.7% of the peri-implantitis subjects, respectively. Only 6.7% subjects revealed submucosal test species resistant in vitro to both amoxicillin and metronidazole, which were either S. constellatus (one subject) or ciprofloxacin-susceptible strains of gram-negative enteric rods/pseudomonads (seven subjects). Overall, 71.7% of the 120 peri-implantitis subjects exhibited submucosal bacterial pathogens resistant in vitro to one or more of the tested antibiotics.

CONCLUSIONS

Peri-implantitis patients frequently yielded submucosal bacterial pathogens resistant in vitro to individual therapeutic concentrations of clindamycin, amoxicillin, doxycycline, or metronidazole, but only rarely to both amoxicillin and metronidazole. Due to the wide variation in observed drug resistance patterns, antibiotic susceptibility testing of cultivable submucosal bacterial pathogens may aid in the selection of antimicrobial therapy for peri-implantitis patients.

Antibiotic susceptibility of periodontal Enterococcus faecalis

BACKGROUND

Enterococcus faecalis may contribute to periodontal breakdown in heavily infected subgingival sites, particularly in patients responding poorly to mechanical forms of periodontal therapy. Because only limited data are available on the antimicrobial sensitivity of enterococci of subgingival origin, this study evaluates the in vitro antibiotic susceptibility of E. faecalis isolated from periodontitis patients in the United States.

METHODS

Pure cultures of 47 subgingival E. faecalis clinical isolates were each inoculated onto specially prepared broth microdilution susceptibility panels containing vancomycin, teicoplanin, and six oral antibiotics of potential use in periodontal therapy. After incubation in ambient air for 18 to 20 hours, minimal inhibitory drug concentrations were determined using applicable Clinical and Laboratory Standards Institute criteria and interpretative guidelines. The organisms were additionally evaluated for in vitro resistance to metronidazole at 4 μg/mL.

RESULTS

Periodontal E. faecalis exhibited substantial in vitro resistance to tetracycline (53.2% resistant), erythromycin (80.8% resistant or intermediate resistant), clindamycin (100% resistant to 2 μg/mL), and metronidazole (100% resistant to 4 μg/mL). In comparison, the clinical isolates were generally sensitive to ciprofloxacin (89.4% susceptible; 10.6% intermediate resistant) and 100% susceptible in vitro to ampicillin, amoxicillin/clavulanate, vancomycin, and teicoplanin.

CONCLUSIONS

Tetracycline, erythromycin, clindamycin, and metronidazole revealed poor in vitro activity against human subgingival E. faecalis clinical isolates, and would likely be ineffective therapeutic agents against these species in periodontal pockets. Among orally administered antibiotics, ampicillin, amoxicillin/clavulanate, and ciprofloxacin exhibited marked in vitro inhibitory activity against periodontal E. faecalis, and may be clinically useful in treatment of periodontal infections involving enterococci.

Relationship between Gram negative enteric rods, Aggregatibacter actinomycetemcomitans, and clinical parameters in periodontal disease

BACKGROUND

The association between Gram negative enteric rods and Aggregatibacter actinomycetemcomitans in periodontal diseases has received little attention in the literature. The objective of this study was to explore the relationship between these organisms and clinical parameters of periodontal disease.

MATERIALS AND METHODS

Clinical parameters and occurrence of Gram-negative enteric rods and A. actinomycetemcomitans were examined in 76 patients with chronic periodontitis. Chi-square and Mann-Whitney tests were used to determine differences in clinical variables versus the presence or absence of both microorganisms. Correlation among both organisms and clinical data were determined using Spearman rank correlation coefficient.

RESULTS

Gram-negative enteric rods and A. actinomycetemcomitans were detected in 20 (26.3%) and 18 (23.7%) individuals, respectively. A total of 14 (18.4%) patients harbored both microorganisms studied. There were significantly positive correlations between enteric rods and presence of A. actinomycetemcomitans (r=0.652, P<0.0001). Both microorganisms were significant and positively correlated with probing depth (PD), clinical attachment level, and bleeding on probing (P<0.0001). The mean PD (mm) of the sampled sites was significantly deeper in patients with presence of A. actinomycetemcomitans and Gram-negative enteric rods.

CONCLUSION

The results of the present study suggest a strong positive correlation between Gram-negative enteric rods and A. actinomycetemcomitans in the population studied. This finding must be taken into account when considering the best therapeutic approach, including the utilization of antimicrobials. The adverse clinical outcomes observed in presence of these microorganisms could have implications in the pathogenesis of periodontal disease and a possible impact on outcomes after treatment.

The Evaluation of Chinese Herbal Medicine Effectiveness on Periodontal Pathogens

The aim of this study was to evaluate the effects of herbal medicines in treating periodontal diseases. Three Chinese herbal composites [Conth Su (CS), Chi Tong Ning (CTN) and Xi Gua Shuang (XGS)], widely used for prevention and treatment of periodontal diseases, and the major components of these composites were tested for their ability to: (1) alleviate disease progression of experimental periodontitis in hamsters, (2) inhibit bacterial growth, and (3) induce mutations. Our results indicate that in treating experimental periodontitis, there were no significant differences between the animal groups with or without the use of Chinese herbal medicines in terms of the degree of inflammation, alveolar bone resorption, and rate of repair. However, hamsters treated with CS presented earlier regenerative epithelium. CTN demonstrated superior bacterial inhibition ability among all tested herbs (MIC 0.025 g/ml); CS showed good anti-bacterial abilities at a concentration of 0.05 g/ml. It is interesting to note that while both CS and CTN were capable of inhibiting bacterial growth, none of the individual herb components showed comparable bacterial inhibition abilities. None of the tested herbal composites or their components showed signs of inducing cell mutations using the Ames test. These results indicated that traditional Chinese herbal medicines, which have been used to treat periodontal diseases for hundreds of years by Chinese people, can effectively inhibit bacterial growth without causing cell mutation. Further investigation into their possible clinical applications in periodontal therapy is encouraged.

Gut microbiota and diabetes: from pathogenesis to therapeutic perspective

More than several hundreds of millions of people will be diabetic and obese over the next decades in front of which the actual therapeutic approaches aim at treating the consequences rather than causes of the impaired metabolism. This strategy is not efficient and new paradigms should be found. The wide analysis of the genome cannot predict or explain more than 10-20% of the disease, whereas changes in feeding and social behavior have certainly a major impact. However, the molecular mechanisms linking environmental factors and genetic susceptibility were so far not envisioned until the recent discovery of a hidden source of genomic diversity, i.e., the metagenome. More than 3 million genes from several hundreds of species constitute our intestinal microbiome. First key experiments have demonstrated that this biome can by itself transfer metabolic disease. The mechanisms are unknown but could be involved in the modulation of energy harvesting capacity by the host as well as the low-grade inflammation and the corresponding immune response on adipose tissue plasticity, hepatic steatosis, insulin resistance and even the secondary cardiovascular events. Secreted bacterial factors reach the circulating blood, and even full bacteria from intestinal microbiota can reach tissues where inflammation is triggered. The last 5 years have demonstrated that intestinal microbiota, at its molecular level, is a causal factor early in the development of the diseases. Nonetheless, much more need to be uncovered in order to identify first, new predictive biomarkers so that preventive strategies based on pre- and probiotics, and second, new therapeutic strategies against the cause rather than the consequence of hyperglycemia and body weight gain.

Periodontal treatment effects on endothelial function and cardiovascular disease biomarkers in subjects with chronic periodontitis: protocol for a randomized clinical trial

Background

Periodontal disease (PD) is an infectious clinical entity characterized by the destruction of supporting tissues of the teeth as the result of a chronic inflammatory response in a susceptible host. It has been proposed that PD as subclinical infection may contribute to the etiology and to the pathogenesis of several systemic diseases including Atherosclerosis. A number of epidemiological studies link periodontal disease/edentulism as independent risk factor for acute myocardial infarction, peripheral vascular disease, and cerebrovascular disease. Moreover, new randomized controlled clinical trials have shown an improvement on cardiovascular surrogate markers (endothelial function, sICAM, hsPCR level, fibrinogen) after periodontal treatment. Nonetheless, such trials are still limited in terms of external validity, periodontal treatment strategies, CONSORT-based design and results consistency/extrapolation. The current study is designed to evaluate if periodontal treatment with scaling and root planning plus local delivered chlorhexidine improves endothelial function and other biomarkers of cardiovascular disease in subjects with moderate to severe periodontitis.

Methods/Design

This randomized, single-blind clinical trial will be performed at two health centers and will include two periodontal treatment strategies. After medical/periodontal screening, a baseline endothelium-dependent brachial artery flow-mediated dilatation (FMD) and other systemic surrogate markers will be obtained from all recruited subjects. Patients then will be randomized to receive either supragingival/subgingival plaque cleaning and calculus removal plus chlorhexidine (treatment group) or supragingival plaque removal only (control group). A second and third FMD will be obtained after 24 hours and 12 weeks in both treatment arms. Each group will consist of 49 patients (n = 98) and all patients will be followed-up for secondary outcomes and will be monitored through a coordinating center. The primary outcomes are FMD differences baseline, 24 hours and 3 months after treatment. The secondary outcomes are differences in C-reactive protein (hs-CRP), glucose serum levels, blood lipid profile, and HOMA index.

Discussion

This RCT is expected to provide more evidence on the effects of different periodontal treatment modalities on FMD values, as well as to correlate such findings with different surrogate markers of systemic inflammation with cardiovascular effects.

Trial registration number

ClinicalTrials.gov Identifier: NCT00681564.

Development of an animal model for Aggregatibacter actinomycetemcomitans biofilm-mediated oral osteolytic infection: a preliminary study

BACKGROUND

Biofilm-induced inflammatory osteolytic oral infections, such as periodontitis and peri-implantitis, have complex etiology and pathogenesis. A significant obstacle to research has been the lack of appropriate animal models where the inflammatory response to biofilms can be investigated. The aim of this study is to develop a novel animal model to study the host response to Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans)-biofilm colonizing titanium implants.

METHODS

Titanium implants were inoculated in vitro with A. actinomycetemcomitans, establishing a biofilm for 1 to 3 days. Biofilm-inoculated and control implants were transmucosally placed into rat hard palate or alveolar ridge. Analysis included documentation of clinical inflammation, polymerase chain reaction, and culture detection of A. actinomycetemcomitans and microcomputed tomography quantitation of peri-implant bone volume.

RESULTS

Viable A. actinomycetemcomitans biofilm was successfully established on titanium implants in vitro, detected by confocal laser scanning microscopy. An inflammatory response characterized by clinical inflammation, bleeding, ulceration, hyperplasia, and necrosis was observed around biofilm-inoculated implants. A. actinomycetemcomitans was detected by polymerase chain reaction and culture analysis on 100% of biofilm-inoculated implants for up to 3 weeks and 25% for up to 6 weeks. Microcomputed tomography analysis demonstrated significantly lower bone volume (P <0.05) around biofilm-inoculated implants (29.6% ± 7.6%) compared to non-inoculated implants (50.5% ± 9.6%) after 6 weeks.

CONCLUSIONS

These results describe a novel animal model where A. actinomycetemcomitans biofilm was established in vitro on titanium implants before placement in rat oral cavity, leading to an inflammatory response, osteolysis, and tissue destruction. This model may have potential use for investigation of host responses to biofilm pathogens and antibiofilm therapy.

Antibiotic resistance of subgingival species in chronic periodontitis patients

BACKGROUND AND OBJECTIVE

The increasing rate of resistance of microorganisms to penicillin and other antibiotics has generated concern among health authorities in Latin America. The present investigation determined the in vitro susceptibility of Porphyromonas gingivalis, Fusobacterium nucleatum, black-pigmented Prevotella spp. and Aggregatibacter actinomycetemcomitans to metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin in patients with chronic periodontitis.

MATERIAL AND METHODS

Subgingival plaque samples from patients with periodontitis were collected and cultured on selective and nonselective culture media. The antimicrobial susceptibility of periodontopathogenic isolates was studied in chronic periodontitis patients in Colombia. Metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin were tested on all bacterial isolates and the percentage of resistant strains was calculated.

RESULTS

Of the 150 bacteria identified, 51 were P. gingivalis, 45 were black-pigmented Prevotella spp., 36 were F. nucleatum and 18 were A. actinomycetemcomitans. All the isolates were sensitive to amoxicillin/clavulanic acid and to moxifloxacin, but exhibited variable susceptibility patterns to the other antimicrobial agents tested.

CONCLUSION

The results of the present study suggest that periodontal microorganisms in patients with chronic periodontitis can be resistant to the antimicrobial agents commonly used in anti-infective periodontal therapy. We suggest that the indiscriminate use of antimicrobials could result in the appearance of more highly antibiotic-resistant strains of bacteria associated with periodontal diseases in our population compared with the populations of other countries.

Bone microbial contamination influences autogenous grafting in sinus augmentation

BACKGROUND

The oral occurrence of putative microbial pathogens in humans has been documented in health and disease. The presence of periodontopathogens in patients with a history of periodontal disease may have a negative impact on bone regeneration. This investigation was conducted to confirm the presence of periodontal pathogens in bone particles harvested intraorally for maxillary sinus augmentation and to assess the clinical and radiographic outcomes 6 to 12 months after bone augmentation.

METHODS

Culture and polymerase chain reaction (PCR)-based identification were performed by paper-point sampling of intraorally harvested bone particles in a group of 12 maintenance patients undergoing maxillary sinus augmentation. Radiographs were taken to assess and compare bone healing and volume gain at baseline and at 6 to 12 months after augmentation.

RESULTS

The presence of periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans [previously Actinobacillus actinomycetemcomitans], Prevotella intermedia, Tannerella forsythia [previously T. forsythensis], Fusobacterium nucleatum, Parvimonas micra [previously Peptostreptococcus micros or Micromonas micros], Campylobacter rectus, enteric Gram-negative rods, and Dialister pneumosintes) was identified in 10 of 12 patients (83%) by culture, PCR, or both and was associated with greater bone volume loss at 6 months postaugmentation. The PCR-positive triad, P. gingivalis, A. actinomycetemcomitans, and P. intermedia, was associated with pronounced volume loss of the grafted sinus at 6 months.

CONCLUSIONS

To the best of our knowledge, this is the first study to confirm osseous microbial contamination with major periodontopathogens in individuals undergoing maxillary sinus augmentation with a history of periodontitis. The effect on the grafting outcome translated into bone volume loss in the grafted sinus 6 months postaugmentation. Specific microbial contamination may have an impact on osteogenesis in osseous regeneration.

Principles and applications of polymerase chain reaction in medical diagnostic fields: a review

Recent developments in molecular methods have revolutionized the detection and characterization of microorganisms in a broad range of medical diagnostic fields, including virology, mycology, parasitology, microbiology and dentistry. Among these methods, Polymerase Chain Reaction (PCR) has generated great benefits and allowed scientific advancements. PCR is an excellent technique for the rapid detection of pathogens, including those difficult to culture. Along with conventional PCR techniques, Real-Time PCR has emerged as a technological innovation and is playing an ever-increasing role in clinical diagnostics and research laboratories. Due to its capacity to generate both qualitative and quantitative results, Real-Time PCR is considered a fast and accurate platform. The aim of the present literature review is to explore the clinical usefulness and potential of both conventional PCR and Real-Time PCR assays in diverse medical fields, addressing its main uses and advances.

Clinical and microbiological determinants of ailing dental implants

BACKGROUND

The failure of the host tissue to establish or maintain osseointegration around dental implants is due to either occlusal or parafunctional forces, premature loading, ill-directed stress, or microbial infection. The long-term failure rate of dental implants is generally 5-10%. Although a variety of etiologies of early peri-implant bone loss (from implant placement to 1-year post-loading) have been proposed, factors associated with late implant failures are less well understood but are probably related to both the peri-implant microbial environment and host factors. Discriminating between causes of implant failure is of importance for instituting a successful implant therapy.

PURPOSE

The objective of this cross-sectional split-mouth study was to identify clinical, radiographic, and bacterial characteristics of peri-implant disease sites.

MATERIALS AND METHODS

Fifteen patients with bilateral implants (Brånemark, Nobel Biocare AB, Göteborg, Sweden; and 3i implant systems, Implant Innovations Inc., Palm Beach Gardens, FL, USA) participated in the study. Sites with peri-implant (radiographic bone loss beyond the third implant thread) and peri-implant healthy tissues (radiographic bone level above the first implant thread) were identified in periapical radiographs using a long-cone paralleling projection technique. Microbiological identification was carried out using established anaerobic culture techniques. A descriptive statistics based on means and standard deviations was reported.

RESULTS

Peri-implant bone loss was associated with the absence of radiographic crestal lamina dura, peri-implant pocket depth, pain on chewing, and the submucosal presence of the putative periodontopathogens Tannerella forsythia, Campylobacter species, and Peptostreptococcus micros. Pain was associated with P. micros, Fusobacterium species, and Eubacterium species.

DISCUSSION AND CONCLUSION

The absence of radiographic crestal lamina dura and the presence of suspected major periodontal pathogens seem to be associated to peri-implantitis.

Doxycycline sustained release from brushite cements for the treatment of periodontal diseases

Doxycycline (DOXY) is a wide spectrum antibiotic used in the treatment of dental, periodontal, and bone infections. Brushite cements are calcium phosphate biomaterials especially interesting for bone regeneration processes. In this work, we describe the preparation of a brushite cement containing DOXY and the drug release from the cement. DOXY solutions were mixed with the cement powder and after a 50% burst release in the first 12 h, a slow and controlled release was achieved over 3.5 days. The release of DOXY hyclate was controlled by both, diffusion and Ca(2+) interaction. Formation of DOXY-Ca(2+) chelates was detected in the cement structure using solid state fluorescence. The brushite cement loaded with DOXY hyclate had antibacterial activity against periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides frosthytus. This new biomaterial may be helpful for the treatment of periodontal diseases.

Periodontal disease severity is related to high levels of C-reactive protein in pre-eclampsia

OBJECTIVE

Recent studies have shown that pre-eclamptic women present a high prevalence of periodontitis, suggesting that active periodontal disease may play a role in the pathogenesis of pre-eclampsia. The present study analysed the effect of periodontal disease in the concentrations of serum high-sensitivity C-reactive protein (hs-CRP), and its association with pre-eclampsia.

METHODS

A case-control study was carried out in Cali-Colombia, comprised of 398 pregnant women (145 cases and 253 controls) who were believed to have periodontal disease, between 28 and 36 weeks of gestational age. Pre-eclampsia cases were defined as blood pressure > or = 140/90 mmHg and proteinuria > or = 0.3 g/24 h. Controls were pregnant women with normal blood pressure, without proteinuria, matched by maternal age, gestational age and body mass index. Sociodemographic data, obstetric risk factors, periodontal state, subgingival microbial composition and hs-CRP levels were determined in both groups.

RESULTS

The case and control groups were comparable for sociodemographic characteristics. In women with pre-eclampsia and confirmed periodontal disease (n = 138), hs-CRP levels increased according to the severity of the disease (gingivitis median 4.14 mg/dl; mild periodontitis median 4.70 mg/dl; moderate/severe periodontitis median 8.8 mg/dl; P = 0.01). A similar tendency was observed in controls with periodontal disease (n = 251), but it did not reach statistical significance (gingivitis median 5.10 mg/dl; mild periodontitis median 5.12 mg/dl; moderate/severe periodontitis median 6.90 mg/dl; P = 0.07). A significant difference in hs-CRP levels was observed in pre-eclamptic women with moderate/severe periodontitis compared to controls (P = 0.01).

CONCLUSION

These findings suggest that chronic periodontitis may increase hs-CRP levels in pregnant women and lead to complications such as pre-eclampsia.

Occurrence of Periodontopathic and Superinfecting Bacteria in Chronic and Aggressive Periodontitis Subjects in a Colombian Population

BACKGROUND

Differences in the composition of subgingival microbiota in periodontitis have been observed in different geographic locations. Some of these microbial differences could have clinical significance. This study describes clinical parameters and the composition of the subgingival microbiota in chronic periodontitis (CP) and aggressive periodontitis (AgP) patients in a Colombian population.

METHODS

Clinical parameters (probing depth, clinical attachment level, bleeding on probing, and plaque index) and plaque samples from 68 CP, 12 AgP, and 30 periodontally healthy subjects were analyzed. Subgingival samples were processed using culture, biochemical tests, and polymerase chain reaction for the detection of periodontal and superinfecting pathogens. The analysis of variance, chi(2), and Kruskal-Wallis tests were used to evaluate differences between groups for clinical parameters and microbiologic composition (P <or=0.05).

RESULTS

Clinical parameters were significantly increased in CP and AgP patients compared to healthy subjects (P <0.001), but no differences were found between periodontitis groups. Porphyromonas gingivalis, Tannerella forsythensis, and Eikenella corrodens showed higher frequencies in AgP compared to CP and healthy subjects (P <0.05). Extension (localized and generalized) of the periodontal destruction had no effect on the composition of the subgingival microbiota. Gram-negative enteric rods were more frequent in AgP patients (P <0.01).

CONCLUSIONS

This study demonstrated a high prevalence of P. gingivalis, T. forsythensis, and E. corrodens in AgP patients. Gram-negative enteric rods were frequent in AgP and CP patients. Differences in the composition of subgingival microbiota in periodontitis patients need to be taken into account when considering the best therapeutic approach for each individual, including the use of antibiotics.

Carpegen�real-time polymerase chain reaction vs. anaerobic culture for periodontal pathogen identification

BACKGROUND/AIMS

The aim of this study was to compare two methods of microbiological diagnosis, anaerobic bacterial culture and real-time polymerase chain reaction (PCR), for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, and Treponema denticola.

METHODS

Seventy-two samples were collected from 18 patients who were suffering from aggressive periodontitis. The data obtained were compared for the two methods.

RESULTS

The results obtained with real-time PCR were different from those obtained with bacterial culture. The detection differences were 3% for A. actinomycetemcomitans, 8.33% for P. intermedia, and 12.5% for F. nucleatum. However, the differences for P. gingivalis and T. forsythia were 51.39% and 36.11%, respectively. No comparison was possible for T. denticola because it cannot be identified in culture. The variations found were the result of the better detection level (10(2) pathogens) of the PCR probe. Unlike bacterial culture, PCR allows the detection of T. denticola, which does not forming colonies and is oxygen sensitive. For F. nucleatum, T. forsythia and P. gingivalis, the real-time PCR technique was more sensitive than culture.

CONCLUSION

Good results were obtained with the real-time PCR technique for the six periopathogens targeted. This method seems to be indicated for its simplicity, rapidity and reproducibility but it cannot analyze data for an antibiotic susceptibility test. The periodontist must therefore choose one of these two methods according to his specific clinical objective: to obtain rapid, specific detection even with weak initial concentrations (but for targeted periopathogens only) or to be non-specific and analyze the pathological activity with an antibiogram.

Changes in the subgingival microbiota and periodontal parameters before and 3 months after bracket placement

INTRODUCTION

Dental plaque is organized in a biofilm complex that provides protection and nutrients for periodontopathic bacteria. Several factors can affect microbial colonization, including restorations and orthodontic brackets. The aim of this study was to investigate changes in subgingival microbiota and clinical parameters before and after bracket placement.

METHODS

Clinical parameters and subgingival microbial samples were collected from 30 patients before and after bracket placement. Thirty additional patients with no orthodontic treatment served as controls. Samples were cultured and analyzed for periodontopathic and superinfecting bacteria. A descriptive analysis was conducted, and chi-square, Student t, Wilcoxon matched, and Mann Whitney rank sum tests were used to test for differences between groups (P < or=.05).

RESULTS

No changes in probing depth or clinical attachment level were observed, but scores for bleeding on probing, plaque index, and gingival index increased after bracket placement (P < or =.05). Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens, Tannerella forsythia, and Fusobacterium species were elevated in the experimental group after bracket placement compared with the control group (P < or =.01). Superinfecting microorganisms such as Enterobacter cloacae, Klebsiella oxytoca, Klebsiella pneumoniae, and Serratia marcescens were also found.

CONCLUSIONS

Bracket placement influences the accumulation of plaque and the colonization of important periodontopathic and superinfecting bacteria, resulting in more inflammation and bleeding. Special attention should be paid to oral hygiene methods in orthodontic patients.

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis subgingival presence, species-specific serum immunoglobulin G antibody levels, and periodontitis disease recurrence

BACKGROUND AND OBJECTIVE

The biological and clinical effects of antibody against periodontal pathogenic bacteria are incompletely understood. This study evaluated the inter-relationships among periodontal levels of cultivable Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, species-specific serum immunoglobulin G (IgG) antibody levels, and periodontitis disease activity.

MATERIAL AND METHODS

Forty-three adults who had previously been treated for periodontitis and who also harbored cultivable A. actinomycetemcomitans or P. gingivalis were evaluated semiannually for clinical disease recurrence over a 36-month period. Each patient provided subgingival microbial samples, for the recovery of A. actinomycetemcomitans and P. gingivalis, from the two deepest pockets in each dentition sextant. A. actinomycetemcomitans and P. gingivalis serum IgG antibody levels were assessed using enzyme-linked immunosorbent assay (ELISA), together with whole-cell sonicate extracts from A. actinomycetemcomitans serotypes a-c and P. gingivalis ATCC 33277. Data were analyzed using the Mantel-Haenszel chi-square and Fisher exact two-tailed tests.

RESULTS

Eighteen (60.0%) of 30 A. actinomycetemcomitans-positive subjects, and 10 (76.9%) of 13 P. gingivalis-positive subjects, exhibited recurrent periodontal breakdown within 36 months of periodontal therapy. Nineteen (67.9%) of the 28 patients with active periodontitis had A. actinomycetemcomitans or P. gingivalis serum antibody levels below designated threshold values. In comparison, 10 (66.7%) of 15 culture-positive clinically stable subjects showed A. actinomycetemcomitans or P. gingivalis serum antibody levels above threshold values. The difference between specific antibody levels in periodontitis-active and periodontitis-stable patients was statistically significant (p = 0.032).

CONCLUSIONS

Serum levels of IgG antibodies against A. actinomycetemcomitans or P. gingivalis in periodontitis-stable patients were higher than those in patients with active periodontitis. The results suggest that elevated levels of IgG antibody against A. actinomycetemcomitans and P. gingivalis have a detectable protective effect against periodontal infections with these microorganisms.

Periodontitis is associated with preeclampsia in pregnant women

BACKGROUND

Recent investigations have demonstrated a positive association between periodontitis and pregnancy complications. The purpose of this study was to determine the effect of periodontitis and the subgingival microbial composition on preeclampsia.

METHODS

A case-control study was carried out in Cali, Colombia that included 130 preeclamptic and 243 non-preeclamptic women between 26 to 36 weeks of pregnancy. Sociodemographic data, obstetric risk factors, periodontal status, and subgingival microbial composition were determined in both groups. Preeclampsia was defined as blood pressure>or=140/90 mm Hg, and >or=2+ proteinuria, confirmed by 0.3 g proteinuria/24 hours of urine specimens. Controls were healthy pregnant women. Odds ratios (ORs) for periodontitis and subgingival microbiota compositions were calculated.

RESULTS

A total of 83 out of 130 preeclamptic women (63.8%) and 89 out of 243 controls (36.6%) had chronic periodontitis (OR: 3.0; 95% confidence interval (CI): 1.91 to 4.87; P<0.001). Clinical attachment loss increased in the case group (4.0+/-0.10 mm) compared to the control group (3.0+/-0.08 mm) (P<0.001). The average newborn birth weight from preeclamptic mothers was 2.453 g, whereas in controls was 2.981 g (P<0.001). Two red complex microorganisms, Porphyromonas gingivalis and Tannerella forsythensis, and the green complex microorganism Eikenella corrodens were more prevalent in the preeclamptic group than in controls (P<0.01).

CONCLUSIONS

Chronic periodontal disease and the presence of P. gingivalis, T. forsythensis, and E. corrodens were significantly associated with preeclampsia in pregnant women. Further research is needed to establish pathogenic mechanisms of active periodontal disease and subgingival periodontopathogens related to preeclampsia development.

Evaluation of subgingival bacterial plaque changes and effects on periodontal tissues in patients with renal transplants under immunosuppressive therapy

OBJECTIVE

The purpose of this study was to identify the presence of periodontal microrganisms in 35 renal transplant patients before the transplant procedure.

STUDY DESIGN

At each time point, clinical parameters were recorded and subgingival plaque samples were collected from 4 different sites at days 30 and 90 after surgery. Samples were plated onto selective and nonselective media to determine total colony counts and the presence of putative periodontal pathogens. After transplant surgery, patients received immunosuppressive therapy.

RESULTS

Statistical analysis of the microbiologic data showed significant changes between time points. An increase in total counts of microrganisms was observed on day 90 after surgery. As a side effect of cyclosporine, 14 patients developed gingival overgrowth. Beta-hemolytic Streptococcus was more frequently detected in patients who did not present gingival overgrowth 90 days after surgery.

CONCLUSION

Quantitative and qualitative changes of the subgingival microflora can occur 90 days after transplant surgery, while patients are still under immunosupressive drugs.

Characterization of Serratia marcescens isolates from subgingival biofilm, extraoral infections and environment by prodigiosin production, serotyping, and genotyping

INTRODUCTION

Serratia marcescens is widely distributed in nature, and has emerged in the last years as an important nosocomial pathogen. The organism may also be found in subgingival biofilm in periodontitis patients. This study aimed to verify the subgingival prevalence of S. marcescens in different periodontal conditions and to evaluate whether the oral cavity would harbor strains similar to those causing infectious diseases.

METHODS

The subgingival occurrence of S. marcescens was determined in 334 subjects. The phenotypic and genotypic diversity of 23 isolates from subgingival biofilm, 22 from extra-oral infections and 10 environmental strains, was compared by prodigiosin production, O and H serotyping and genotyping using polymorphic GC-rich repetitive sequences-polymerase chain reaction.

RESULTS

S. marcescens was found more frequently in severe periodontitis patients (4.1%) than in gingivitis (3.2%) and healthy subjects (2.5%), but these differences were not statistically significant. Analysis of serotype distribution, prodigiosin production, and genotyping revealed that environmental strains were markedly different from most human isolates, either oral or extraoral.

CONCLUSION

These data suggest that S. marcescens isolates from subgingival biofilm are not just contaminants from the environment, but that the oral cavity may act as a reservoir of strains able to promote human infections. However, further studies are needed to elucidate the role of this bacterium in the pathogenesis of periodontal diseases.

Oral lactobacilli in chronic periodontitis and periodontal health: species composition and antimicrobial activity

BACKGROUND/AIMS

Lactobacilli are known to play an important role in the maintenance of health by stimulating natural immunity and contributing to the balance of microflora. However, their role in chronic periodontitis is unclear. We aimed to identify oral lactobacilli in chronic periodontitis and periodontally healthy subjects, and to determine their antimicrobial activity against putative oral pathogens.

METHODS

A total of 238 Lactobacillus isolates from the saliva and subgingival sites of 20 chronic periodontitis and 15 healthy subjects were collected. In all, 115 strains were identified using rapid amplified ribosomal DNA restriction analysis. Antimicrobial activity against Streptococcus mutans, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed.

RESULTS

Lactobacilli belonging to 10 species were identified. The most prevalent strains in healthy persons were Lactobacillus gasseri and Lactobacillus fermentum and in chronic periodontitis patients, Lactobacillus plantarum. Obligately homofermentatives, particularly L. gasseri, were less prevalent in chronic periodontitis patients compared with healthy subjects (8% vs. 64% for L. gasseri, P < 0.01). Sixty-nine percent of tested lactobacilli inhibited S. mutans, 88% A. actinomycetemcomitans, 82% P. gingivalis and 65% P. intermedia. The strongest antimicrobial activity was associated with Lactobacillus paracasei, L. plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. The strains from periodontally healthy patients showed a lower antimicrobial activity against S. mutans than the strains from chronic periodontitis patients.

CONCLUSION

The composition of oral lactoflora in chronic periodontitis and healthy subjects differs, with a higher prevalence of homofermentative lactobacilli, particularly L. gasseri, in the latter group. Both homo- and heterofermentative oral lactobacilli suppress the growth of periodontal pathogens, but the antimicrobial properties are strain, species and origin specific.