Microbiological study of HIV-related periodontitis

The microbiota as a modulator of mucosal inflammation and HIV/HPV pathogenesis: From association to causation

Although the microbiota has largely been associated with the pathogenesis of viral infections, most studies using omics techniques are correlational and hypothesis-generating. The mechanisms affecting the immune responses to viral infections are still being fully understood. Here we focus on the two most important sexually transmitted persistent viruses, HPV and HIV. Sophisticated omics techniques are boosting our ability to understand microbiota-pathogen-host interactions from a functional perspective by surveying the host and bacterial protein and metabolite production using systems biology approaches. However, while these strategies have allowed describing interaction networks to identify potential novel microbiota-associated biomarkers or therapeutic targets to prevent or treat infectious diseases, the analyses are typically based on highly dimensional datasets -thousands of features in small cohorts of patients-. As a result, we are far from getting to their clinical use. Here we provide a broad overview of how the microbiota influences the immune responses to HIV and HPV disease. Furthermore, we highlight experimental approaches to understand better the microbiota-host-virus interactions that might increase our potential to identify biomarkers and therapeutic agents with clinical applications.

Presence of non-oral bacteria in the oral cavity

A homeostatic balance exists between the resident microbiota in the oral cavity and the host. Perturbations of the oral microbiota under particular conditions can contribute to the growth of non-oral pathogens that are hard to kill because of their higher resistance to antimicrobials, raising the probability of treatment failure and reinfection. The presence of these bacteria in the oral cavity has been proven to be associated with several oral diseases such as periodontitis, caries, and gingivitis, and systemic diseases of importance in clinical medicine such as cystic fibrosis, HIV, and rheumatoid arthritis. However, it is still controversial whether these species are merely transient members or unique to the oral cavity. Mutualistic and antagonistic interactions between the oral microbiota and non-oral pathogens can also occur, though the mechanisms used by these bacteria are not clear. Therefore, this review presents an overview of the current knowledge about the presence of non-oral bacteria in the oral cavity, their relationship with systemic and oral diseases, and their interactions with oral bacteria.

Current trends and new developments in HIV research and periodontal diseases

With the advent of combined antiretroviral therapies, the face of HIV infection has changed dramatically from a disease with almost certain mortality from serious comorbidities, to a manageable chronic condition with an extended lifespan. In this paper we present the more recent investigations into the epidemiology, microbiology, and pathogenesis of periodontal diseases in patients with HIV, and the effects of combined antiretroviral therapies on the incidence and progression of these diseases both in adults and perinatally infected children. In addition, comparisons and potential interactions between the HIV-associated microbiome, host responses, and pathogenesis in the oral cavity with the gastrointestinal tract and other areas of the body are presented. Also, the effects of HIV and combined antiretroviral therapies on comorbidities such as hyposalivation, dementia, and osteoporosis on periodontal disease progression are discussed.

HIV, Cancer, and the Microbiota: Common Pathways Influencing Different Diseases

HIV infection exerts profound and perhaps irreversible damage to the gut mucosal-associated lymphoid tissues, resulting in long-lasting changes in the signals required for the coordination of commensal colonization and in perturbations at the compositional and functional level of the gut microbiota. These abnormalities in gut microbial communities appear to affect clinical outcomes, including T-cell recovery, vaccine responses, HIV transmission, cardiovascular disease, and cancer pathogenesis. For example, the microbial signature associated with HIV infection has been shown to induce tryptophan catabolism, affect the butyrate synthesis pathway, impair anti-tumoral immunity and affect oxidative stress, which have also been linked to the pathogenesis of cancer. Furthermore, some of the taxa that are depleted in subjects with HIV have proved to modulate the anti-tumor efficacy of various chemotherapies and immunotherapeutic agents. The aim of this work is to provide a broad overview of recent advances in our knowledge of how HIV might affect the microbiota, with a focus on the pathways shared with cancer pathogenesis.

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.

Applications of the FIV Model to Study HIV Pathogenesis

Feline immunodeficiency virus (FIV) is a naturally-occurring retrovirus that infects domestic and non-domestic feline species, producing progressive immune depletion that results in an acquired immunodeficiency syndrome (AIDS). Much has been learned about FIV since it was first described in 1987, particularly in regard to its application as a model to study the closely related lentivirus, human immunodeficiency virus (HIV). In particular, FIV and HIV share remarkable structure and sequence organization, utilize parallel modes of receptor-mediated entry, and result in a similar spectrum of immunodeficiency-related diseases due to analogous modes of immune dysfunction. This review summarizes current knowledge of FIV infection kinetics and the mechanisms of immune dysfunction in relation to opportunistic disease, specifically in regard to studying HIV pathogenesis. Furthermore, we present data that highlight changes in the oral microbiota and oral immune system during FIV infection, and outline the potential for the feline model of oral AIDS manifestations to elucidate pathogenic mechanisms of HIV-induced oral disease. Finally, we discuss advances in molecular biology, vaccine development, neurologic dysfunction, and the ability to apply pharmacologic interventions and sophisticated imaging technologies to study experimental and naturally occurring FIV, which provide an excellent, but often overlooked, resource for advancing therapies and the management of HIV/AIDS.

Interplay between viruses and bacterial microbiota in cancer development

During the last few decades we have become accustomed to the idea that viruses can cause tumors. It is much less considered and discussed, however, that most people infected with oncoviruses will never develop cancer. Therefore, the genetic and environmental factors that tip the scales from clearance of viral infection to development of cancer are currently an area of active investigation. Microbiota has recently emerged as a potentially critical factor that would affect this balance by increasing or decreasing the ability of viral infection to promote carcinogenesis. In this review, we provide a model of microbiome contribution to the development of oncogenic viral infections and viral associated cancers, give examples of this process in human tumors, and describe the challenges that prevent progress in the field as well as their potential solutions.

(B2) Periodontal Diseases and Other Bacterial Infections

The workshop addressed the following questions with respect to periodontal diseases and bacterial infections seen in HIV infection: (1) What is linear gingival erythema? Is it prevalent only in HIV disease? A crude Delphi technique was used to ascertain whether LGE existed, but a consensus could not be reached. It was agreed that a diagnosis of LGE should be considered only if the lesion persists after removal of plaque in the initial visit. (2) Do periodontal pockets contribute to viremia in HIV infection? At present, the data are not available to answer this question. (3) Do anti-viral drugs reach the sulcular fluid in significant concentrations? No one at the workshop was aware of data that could answer this question. (4) Does concurrent tuberculosis infection modify the oral manifestations of HIV infection? Though analysis of data from the developing countries does suggest an association between tuberculosis and oral candidiasis, more data and multivariate analysis considering immunosuppression as a confounding factor are necessary, for any conclusions to be derived. (5) What pathogens are involved in periodontal diseases in HIV infection? Periodontal disease may be initiated by conventional periodontal pathogens. But the progression and tissue destruction depend upon the presence of typical and atypical micro-organisms, including viruses, their by-products, increased secretion of potentially destructive inflammatory mediators, and overwhelming host response. (6) How can we diagnose the diseases seen in HIV infection? The answer can be obtained only with data from controlled and blinded studies. It is necessary to design collaborative multi-center longitudinal studies. The results obtained from such large sample sizes can contribute eventually to interpretation of the outcome.

Non-oral gram-negative facultative rods in chronic periodontitis microbiota

OBJECTIVE

The subgingival prevalence of gram-negative facultative rods not usually inhabiting or indigenous to the oral cavity (non-oral GNFR), as well as selected periodontal bacterial pathogens, were evaluated by culture in untreated and treated chronic periodontitis patients.

METHODS

Subgingival biofilm specimens from 102 untreated and 101 recently treated adults with chronic periodontitis in the Netherlands were plated onto MacConkey III and Dentaid selective media with air-5% CO2 incubation for isolation of non-oral GNFR, and onto enriched Oxoid blood agar with anaerobic incubation for recovery of selected periodontal bacterial pathogens. Suspected non-oral GNFR clinical isolates were identified to a species level with the VITEK 2 automated system.

RESULTS

A total of 87 (42.9%) out of 203 patients yielded subgingival non-oral GNFR. Patients recently treated with periodontal mechanical debridement therapy demonstrated a greater prevalence of non-oral GNFR (57.4% vs 28.4%, P < 0.0001), and a greater number of different non-oral GNFR species (23 vs 14 different species), than untreated patients. Sphingomonas paucimobilis was the most frequently isolated subgingival non-oral GNFR species. Several GNFR species normally found in animals and human zoonotic infections, and not previously detected in human subgingival biofilms, were recovered from some patients, including Bordetella bronchispetica, Pasteurella canis, Pasteurella pneumotropica and Neisseria zoodegmatis. Porphyromonas gingivalis and Tannerella forsythia were significantly associated with the presence of subgingival non-oral GNFR.

CONCLUSIONS

A surprisingly high proportion of Dutch chronic periodontitis patients yielded cultivable non-oral GNFR in periodontal pockets, particularly among those recently treated with periodontal mechanical debridement therapy. Since non-oral GNFR species may resist mechanical debridement from periodontal pockets, and are often not susceptible to many antibiotics frequently used in periodontal practice, their subgingival presence may complicate periodontal treatment in species-positive patients and increase risk of potentially dangerous GNFR infections developing at other body sites.

Periodontal Conditions in Human Immunodeficiency Virus-Positive Patients Under Highly Active Antiretroviral Therapy From a Metropolitan Area of Rio De Janeiro

BACKGROUND

The aim of this study is to evaluate the periodontal status and the presence of opportunistic oral lesions in human immunodeficiency virus-positive (HIV+) patients under highly active antiretroviral therapy (HAART) and their association with cluster of differentiation (CD)4+ and CD4+ nadir T-cell counts and viral load levels.

METHODS

Clinical periodontal parameters and the presence of opportunistic oral lesions along with records of CD4+ counts and viral load levels were evaluated in 29 individuals (16 females; mean age: 42.7 years) with previous serologic diagnosis of HIV, from the acquired immunodeficiency syndrome program of the Health Center of Duque de Caxias, Rio de Janeiro, Brazil.

RESULTS

All individuals presented gingivitis or periodontitis. A higher non-significant prevalence of periodontitis was found in smokers (93.8%) compared with non-smokers (76.9%). A significant weak positive correlation was observed between CD4+ counts and missing teeth (ρ = 0.380, P <0.05), CD4+ nadir and periodontal diagnosis (ρ = 0.418, P <0.005), and CD4+ nadir and moderate probing depth (PD) (ρ = 0.424, P <0.05). When only non-smokers were analyzed, a significant moderate positive association was found between viral load and moderate clinical attachment level (CAL) (ρ = 0.638, P <0.05), CD4+ nadir and diagnosis (ρ = 0.586, P <0.05), and CD4+ nadir and moderate CAL (ρ = 0.680, P <0.05). Analysis considering only smokers found no correlations between serologic parameters and demographic or clinical parameters.

CONCLUSIONS

The current investigation demonstrates that HIV+ individuals under HAART presents a high prevalence of mild to moderate periodontal disease. Viral load levels, CD4+ nadir, and CD4+ counts may present a weak to moderate correlation to the number of missing teeth, periodontal diagnosis, moderate PD, and moderate CAL, which may also reflect some effect of these systemic conditions on the periodontal status.

Acute periodontal lesions

This review provides updates on acute conditions affecting the periodontal tissues, including abscesses in the periodontium, necrotizing periodontal diseases and other acute conditions that cause gingival lesions with acute presentation, such as infectious processes not associated with oral bacterial biofilms, mucocutaneous disorders and traumatic and allergic lesions. A periodontal abscess is clinically important because it is a relatively frequent dental emergency, it can compromise the periodontal prognosis of the affected tooth and bacteria within the abscess can spread and cause infections in other body sites. Different types of abscesses have been identified, mainly classified by their etiology, and there are clear differences between those affecting a pre-existing periodontal pocket and those affecting healthy sites. Therapy for this acute condition consists of drainage and tissue debridement, while an evaluation of the need for systemic antimicrobial therapy will be made for each case, based on local and systemic factors. The definitive treatment of the pre-existing condition should be accomplished after the acute phase is controlled. Necrotizing periodontal diseases present three typical clinical features: papilla necrosis, gingival bleeding and pain. Although the prevalence of these diseases is not high, their importance is clear because they represent the most severe conditions associated with the dental biofilm, with very rapid tissue destruction. In addition to bacteria, the etiology of necrotizing periodontal disease includes numerous factors that alter the host response and predispose to these diseases, namely HIV infection, malnutrition, stress or tobacco smoking. The treatment consists of superficial debridement, careful mechanical oral hygiene, rinsing with chlorhexidine and daily re-evaluation. Systemic antimicrobials may be used adjunctively in severe cases or in nonresponding conditions, being the first option metronidazole. Once the acute disease is under control, definitive treatment should be provided, including appropriate therapy for the pre-existing gingivitis or periodontitis. Among other acute conditions affecting the periodontal tissues, but not caused by the microorganisms present in oral biofilms, infectious diseases, mucocutaneous diseases and traumatic or allergic lesions can be listed. In most cases, the gingival involvement is not severe; however, these conditions are common and may prompt an emergency dental visit. These conditions may have the appearance of an erythematous lesion, which is sometimes erosive. Erosive lesions may be the direct result of trauma or a consequence of the breaking of vesicles and bullae. A proper differential diagnosis is important for adequate management of the case.

The oral microbiome in human immunodeficiency virus (HIV)-positive individuals

Human immunodeficiency virus (HIV) infection is associated with a range of oral conditions, and increased numbers of disease-associated microbial species have previously been found in HIV-positive subjects. The aim of this study was to use next-generation sequencing to compare the composition of the oral microbiome in HIV-positive and -negative individuals. Plaque and saliva were collected from 37 HIV-positive individuals and 37 HIV-negative individuals, and their bacterial composition determined by pyrosequencing of partial 16S rRNA genes. A total of 855,222 sequences were analysed. The number of species-level operational taxonomic units (OTUs) detected was significantly lower in the saliva of HIV-positive individuals (mean = 303.3) than in that of HIV-negative individuals (mean = 365.5) (P < 0.0003). Principal coordinates analysis (PCoA) based on community membership (Jaccard index) and structure (Yue and Clayton measure of dissimilarity) showed significant separation of plaque and saliva samples [analysis of molecular variance (AMOVA), P < 0.001]. PCoA plots did not show any clear separation based on HIV status. However, AMOVA indicated that there was a significant difference in the community membership of saliva between HIV-positive and -negative groups (P = 0.001). Linear discriminant analysis effect size revealed an OTU identified as Haemophilus parainfluenzae to be significantly associated with HIV-positive individuals, whilst Streptococcus mitis/HOT473 was most significantly associated with HIV-negative individuals. In conclusion, this study has confirmed that the microbial composition of saliva and plaque is different. The oral microbiomes of HIV-positive and -negative individuals were found to be similar overall, although there were minor but significant differences in the composition of the salivary microbiota of the two groups.

Subgingival bacterial community profiles in HIV-infected Brazilian adults with chronic periodontitis

BACKGROUND AND OBJECTIVE

To compare the subgingival microbial diversity between non-HIV-infected and HIV-infected individuals with chronic periodontitis using denaturing gradient gel electrophoresis (DGGE).

MATERIAL AND METHODS

Thirty-two patients were selected: 11 were HIV-infected and 21 were non-HIV-infected, and all had chronic periodontitis. Periodontal measurements included probing depth, clinical attachment level, visible supragingival biofilm and bleeding on probing. Subgingival biofilm samples were collected from periodontal sites (50% with probing depth ≤ 4 mm and 50% with probing depth ≥ 5 mm) and whole-genomic-amplified DNA was obtained. The DNA samples were subjected to amplification of a 16S rRNA gene fragment using universal bacterial primers, followed by DGGE analysis of the amplified gene sequences.

RESULTS

The non-HIV-infected group presented higher mean full-mouth visible supragingival biofilm (p = 0.004), bleeding on probing (p = 0.006), probing depth (p < 0.001) and clinical attachment level (p = 0.001) in comparison with the HIV-infected group. DGGE analysis revealed 81 distinct bands from all 33 individuals. Banding profiles revealed a higher diversity of the bacterial communities in the subgingival biofilm of HIV-infected patients with chronic periodontitis. Moreover, cluster and principal component analyses demonstrated that the bacterial community profiles differed between these two conditions. High interindividual and intra-individual variability in banding profiles were observed for both groups.

CONCLUSION

HIV-infected patients with chronic periodontitis present greater subgingival microbial diversity. In addition, the bacterial communities associated with HIV-infected and non-HIV-infected individuals are different in structure.

The association between detectable plasmatic human immunodeficiency virus (HIV) viral load and different subgingival microorganisms in Brazilian adults with HIV: a multilevel analysis

BACKGROUND

This study investigates the association between detectable plasmatic human immunodeficiency virus (HIV) viral load (HVL) and high levels of periodontal- and non-periodontal-related microorganisms in the subgingival microbiota of individuals with HIV.

METHODS

Thirty-seven individuals with HIV were divided into two groups: 1) detectable HVL (n = 15); and 2) undetectable HVL (n = 22). Subgingival biofilm samples were obtained, and the levels of 35 microbial species were determined by the checkerboard DNA-DNA hybridization method. Periodontal clinical measures and laboratory and sociodemographic data were also registered. χ(2) test, Fisher exact test, and Mann-Whitney U test were used to compare groups. Multilevel ordinal regression models were used to test the association between HVL and the levels of 35 microbial species in subgingival biofilm, adjusted for confounders.

RESULTS

Of the 35 species studied, 11 (31.4%) showed higher mean levels in the detectable HVL group than undetectable HVL group (P <0.001). These species included Actinomyces naeslundii II, Actinomyces israelii, Actinomyces odontolyticus, Veillonella parvula, Capnocytophaga gingivalis, Eikenella corrodens, Campylobacter concisus, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Candida albicans. Significant associations between detectable HVL and high levels of microorganisms, adjusted for confounders, were observed for A. naeslundii I, Actinomyces gerencseriae, C. gingivalis, E. corrodens, C. concisus, Prevotella nigrescens, T. forsythia, and Dialister pneumosintes.

CONCLUSION

Detectable plasmatic HVL in individuals with HIV was associated with elevated levels of known periodontal pathogens, such as P. nigrescens, T. forsythia, and E. corrodens, as well as C. concisus, C. gingivalis, and D. pneumosintes in the subgingival biofilm.

Periodontal disease in HIV-infected adults in the HAART era: Clinical, immunological, and microbiological aspects

The introduction of highly active antiretroviral therapy (HAART) has decreased the incidence and prevalence of several oral manifestations such as oral candidiasis, hairy leukoplakia, and Kaposi's sarcoma in HIV-infected patients. Regarding periodontal disease the findings are not clear. This disease represents a group of chronic oral diseases characterized by infection and inflammation of the periodontal tissues. These tissues surround the teeth and provide periodontal protection (the gingival tissue) and periodontal support (periodontal ligament, root cementum, alveolar bone). Clinical, immunological, and microbiological aspects of these diseases, such as linear gingival erythema (LGE), necrotizing periodontal diseases (NPD) (necrotizing ulcerative gingivitis [NUG], necrotizing ulcerative periodontitis [NUP] and necrotizing stomatitis), and chronic periodontitis, have been widely studied in HIV-infected individuals, but without providing conclusive results. The purpose of this review was to contribute to a better overall understanding of the probable impact of HIV-infection on the characteristics of periodontal infections.

Periodontal disease in HIV/AIDS

Since the early 1990's, the death rate from AIDS among adults has declined in most developed countries, largely because of newer antiretroviral therapies and improved access to these therapies. In addition, from 2006 to 2011, the total number of new cases of HIV infection worldwide has declined somewhat and has remained relatively constant. Nevertheless, because of the large numbers of existing and new cases of HIV infection, the dental practitioner and other healthcare practitioners will still be required to treat oral and periodontal conditions unique to HIV/AIDS as well as conventional periodontal diseases in HIV-infected adults and children. The oral and periodontal conditions most closely associated with HIV infection include oral candidiasis, oral hairy leukoplakia, Kaposi's sarcoma, salivary gland diseases, oral warts, other oral viral infections, linear gingival erythema and necrotizing gingival and periodontal diseases. While the incidence and prevalence of these oral lesions and conditions appear to be declining, in part because of antiretroviral therapy, dental and healthcare practitioners will need to continue to diagnose and treat the more conventional periodontal diseases in these HIV-infected populations. Finding low-cost and easily accessible and acceptable diagnostic and treatment approaches for both the microbiological and the inflammatory aspects of periodontal diseases in these populations are of particular importance, as the systemic spread of the local microbiota and inflammatory products of periodontal diseases may have adverse effects on both the progression of HIV infection and the effectiveness of antiretroviral therapy approaches. Developing and assessing low-cost and accessible diagnostic and treatment approaches to periodontal diseases, particularly in developing countries, will require an internationally coordinated effort to design and conduct standardized clinical trials.

Oral microbial colonization in patients with systemic lupus erythematous: correlation with treatment and disease activity

Treating patients with systemic lupus erythematosus (SLE) with steroids and immunosuppressive drugs may interfere in the presence of potentially opportunistic microorganisms in the oral cavity. The aim of this study was to evaluate the presence of Candida spp., Staphylococcus spp., Enterobacteria and Pseudomonas spp. in the oral cavity of SLE patients, compared with healthy controls. A group of 40 patients who had received therapy for at least 60 days was selected (19-53 years). For the control group, 40 healthy individuals matched for age, gender and use of partial prosthesis were selected. Oral rinse samples were collected and plated on specific culture media. After incubation, the number of colony forming units (CFU) was obtained and the isolates were identified at species level. Microbial counts were compared between SLE and control by analysis of variance (ANOVA) and Mann-Whitney (p < 0.05 significant). Microorganism counts in patients with and without immunosuppressive drugs, as well with active and inactive disease (according to SLEDAI score) were also compared. No significant differences in CFU/mL between SLE and control patients were observed (yeasts, p = 0.55; Staphylococci, p = 0.24; Enterobacteria/Pseudomonas spp., p = 0.26). No differences in microbial counts were observed regarding clinical parameters tested. The most frequent species isolated in the SLE group were Candida albicans, Staphylococcus epidermidis and Klebsiella oxytoca. In conclusion, no differences in frequency and microorganism levels were found between SLE patients and healthy individuals.

Microbiologic profile of endodontic infections from HIV- and HIV+ patients using multiple-displacement amplification and checkerboard DNA-DNA hybridization

OBJECTIVE

To compare the microbiota of endodontic infections in necrotic pulp from HIV-negative and HIV-positive subjects.

MATERIALS AND METHODS

Root canal samples from necrotic pulp were collected from 40 HIV- and 20 HIV+ subjects. Pulps were amplified using multiple displacement amplification (MDA). Then, checkerboard DNA-DNA hybridization was employed to assess the levels of 107 microbial taxa. The percentage of DNA probe count and the percentage of teeth colonized by each test species were investigated. Significant differences between groups regarding proportions of taxa and prevalence of the test species were sought using the Mann-Whitney test and the Chi-square analysis, respectively.

RESULTS

The most prevalent taxa detected were Dialister pneumosintes, Stenotrophomonas maltophilia, Streptococcus sobrinus, Corynebacterium diphteriae, and Helicobacter pylori among HIV- subjects and D. pneumosintes, Prevotella tannerae, Porphyromonas gingivalis, Parvimonas micra, Prevotella nigrescens, and Corynebacterium diphtheriae among HIV+ individuals. D. pneumosintes, C. diphtheria, and C. albicans were the most abundant species in the HIV- group, whereas the predominant taxa in HIV+ samples were P. tannerae, D. pneumosintes and Olsenella uli. P. tannerae, O. uli, Veilonella dispar, Bacteroides fragilis, and Actinomyces meyeri were significantly more abundant in HIV+ samples.

CONCLUSIONS

There were significant differences in the prevalence and proportions of specific microbial taxa between HIV- and HIV+ individuals. The root canal microbiota may represent a reservoir of important oral and medical pathogens, mainly in HIV+ individuals.

Relationship between herpesviruses and periodontopathogens in patients with HIV and periodontitis

BACKGROUND

The purpose of the present study is to verify a possible association between herpesviruses and periodontal pathogens in individuals with human immunodeficiency virus (HIV) and periodontitis.

METHODS

Twenty-seven patients with HIV and chronic periodontitis and 23 patients with HIV and gingivitis were included in the study. Probing depth, clinical attachment loss, gingival index, and plaque index were recorded. Blood, saliva, and subgingival plaque were processed for viral and bacterial identification. Bacteria were identified by 16S rRNA-based polymerase chain reaction and viruses by the nested polymerase chain reaction.

RESULTS

For the chronic periodontitis group, Epstein-Barr (EBV)-1 (70.4%) and Tannerella forsythia (Tf) (51.8%) presented higher detection in subgingival plaque and saliva (81.5% and 40.7%, respectively) than in blood (22% and 0%, respectively) (P <0.005 and P <0.0001, respectively). Porphyromonas gingivalis (Pg) was more frequent in subgingival plaque (77.7%; P <0.0001). In the gingivitis group, Pg and human cytomegalovirus (HCMV) presented higher frequency in subgingival plaque (95.6% and 91.3%, respectively; P <0.0001 and P = 0.004). Tf and EBV-1 were detected more frequently in subgingival plaque (47.8% and 78.3%, respectively) and saliva (52.2% and 52.2%, respectively; P = 0.004 and P <0.005) than in blood. EBV-1, EBV-1-HCMV, and presence of different viruses presented an association with periodontitis in saliva.

CONCLUSIONS

No association was detected for herpesviruses and periodontal pathogens in patients who are HIV-positive with periodontitis. EBV-1 and coinfection (EBV-1-HCMV) were associated with patients who are HIV-positive with periodontitis.

Oral infectious diseases: a potential risk factor for HIV virus recrudescence?

As the highly active antiretroviral therapy (HAART) has transitioned human immunodeficiency virus (HIV) infection into a 'chronic disease' management strategy, there is growing evidence that infection with non-HIV pathogens in HIV+ patients may have important public health implications in undermining HAART success and acquired immunodeficiency syndrome progression. Several bacterial and host cell products during infections with non-HIV pathogens have shown the capacity to regulate HIV replication in latently infected cells. A high prevalence of oral infections caused by bacteria, viruses and fungi has been described in HIV+ patients, including periodontal disease. The oral cavity appears to be a site of HIV pathogenesis and potential reservoir for the disease as HIV RNA and DNA forms are present in saliva as well as in gingival crevicular fluid, and oral epithelial cells are susceptible to either cell free or cell-associated HIV infection. The clinical and biological bases of potential associations between chronic oral inflammatory disorders, such as periodontal disease, and exacerbation of HIV viraemia have received little attention. This review attempts to evaluate the current understanding of HIV reactivation as a result of co-infection and/or inflammation induced by non-HIV pathogens in HIV-infected patients, and presents a hypothetic model about the potential role of periodontitis as a global oral infection that potentially contributes to HIV recrudescence.

Periodontal microflora of HIV infected patients with periodontitis

The aim of this study was to determine the microbial profile of periodontal lesions in HIV seropositive patients and to compare it with rapidly progressing periodontal lesions in systemically healthy patients. The subgingival microflora of 20 CDC II, 20 CDC III, 20 CDC IV/V and 20 systemically healthy patients with rapidly progressing periodontitis was examined. Four sites with greatest probing depth in each patient were selected for microbiological sampling. The samples were cultured aerobically and anaerobically for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. The microflora of periodontitis lesions within the three stages of the HIV infection was similar to that of progressing periodontitis in systemically healthy adults including Campylobacter rectus, Capnocytophaga spp., Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Selenomonas spp. and Peptostreptococcus micros. However, HIV seropositive periodontitis lesions harboured a range of exogenous pathogens rarely associated with common types of periodontitis including Staphylococcus aureus, Enterobacter cloaca, Pseudomonas aeruginosa, Candida albicans, Enterococcus faecalis, Enterococcus avium, Clostridium difficile, Aspergillus fumigatus, Klebsiella pneumoniae and Mycoplasma incognitum. The lack of immune effector and regulatory cells in HIV infected patients could in fact explain the increase of some opportunistic pathogens and the characteristic and rapidly progressing nature of the periodontal disease in these patients.

Subgingival microflora in smokers with early onset periodontitis

Cigarette smoking is a potent risk factor which has recently been associated with periodontal disease progression. The objective of this study was to detect the microbial profile of early onset periodontitis in smokers and compare it to that of non-smokers. The study population consisted of 50 systemically healthy individuals aged 25 to 38 years, exhibiting early onset periodontitis. 25 patients were smokers (> 20 cigarettes/day) and 25 non-smokers. Two pooled bacterial samples comprised of four periodontal sites with probing depth > 5 mm each, were collected from each individual. The samples were cultured aerobically and anaerobically for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. The differences in bacterial counts using the Mann Whitney U test were statistically significant for Staphylococcus aureus, Campylobacter concisus, Eikenella corrodens, Escherichia coli, Bacteroides forsythus, Bacteroides gracilis, Campylobacter rectus, Porphyromonas gingivalis, Selenomonas sputigena and Candida albicans in smokers. Statistically significant differences for Peptostreptococcus micros, Actinomyces naeslundii, Eubacterium lentum and Capnocytophaga gingivalis were detected in non-smokers. The isolation of bacteria belonging to the exogenous flora like E. coli, C. albicans and S. aureus in smokers microflora underscores the importance of the host which is adversely affected by cigarette smoking.

Subgingival plaque microbiota in HIV positive patients

AIM

To describe and compare the predominant bacterial and fungal species associated with gingivitis, periodontitis, and linear gingival erythema (LGE), in HIV positive subjects with different immune status.

METHODS

Viral loads and CD4 levels determined HIV disease status. From pooled subgingival plaque, 16S and 18S rDNA were cloned and sequenced to determine species identity.

RESULTS

One hundred and nine bacterial species were identified from 14 subjects. Nearly half of the species were not cultivable. Notably, the classical putative periodontal pathogens, Treponema denticola, Porphyromonas gingivalis and Tannerella forsythia were below the limit of detection and were not detected. Species of Gemella, Dialister, Streptococcus and Veillonella were predominant. In one HIV positive subject with periodontitis and low viral load, Gemella morbillorum, a known opportunistic pathogen, constituted 84% of the clones. Saccharomyces cerevisiae was the only fungal species detected in an LGE subject and in periodontitis subjects with high viral loads. In periodontitis patients with low viral loads, Candida albicans was predominant, while S. cerevisiae was only a minor component.

CONCLUSION

These case studies suggest that other bacterial species, rather than the classical periodontal pathogens, may be involved in periodontal diseases of subjects with HIV. These data are indicative of opportunistic infections in a highly susceptible immunocompromised host.

Clinical and microbiological profiles of human immunodeficiency virus (HIV)-seropositive Brazilians undergoing highly active antiretroviral therapy and HIV-seronegative Brazilians with chronic periodontitis

BACKGROUND

This study compares the periodontal clinical profile and the composition of the subgingival microbiota of human immunodeficiency virus (HIV)-seropositive and HIV-seronegative subjects with chronic periodontitis.

METHODS

A total of 172 subjects were distributed into two HIV-seropositive groups (37 chronic periodontitis [H+CP+] and 35 periodontally healthy [H+CP-] individuals) and two HIV-seronegative groups (49 chronic periodontitis [H-CP+] and 51 periodontally healthy [H-CP-] subjects). Subgingival samples were collected from six sites with the deepest probing depth in the periodontitis groups and six random sites in the groups with periodontal health. All HIV-infected patients had undergone highly active antiretroviral therapy (HAART) for at least 2 years. The presence and levels of 33 bacterial species were detected by DNA probes and the checkerboard method. Kruskal-Wallis and Mann-Whitney tests were used to seek for significant differences among and between groups.

RESULTS

H-CP+ patients showed significantly more periodontal destruction and inflammation than H+CP+ patients, whereas H+CP- subjects presented a greater percentage of sites with bleeding than H-CP- subjects (P <0.01). Patients who were HIV seronegative showed higher prevalence and levels of most bacterial species than HIV seropositive patients. Periodontal pathogens including Tannerella forsythensis, Porphyromonas gingivalis, Prevotella nigrescens, Eubacterium nodatum, Fusobacterium nucleatum, and Selenomonas noxia were more frequently detected in H-CP+ subjects compared to H+CP+ and controls. In contrast, Enterococcus faecalis and Acinetobacter baumannii were more commonly found in HIV-infected than in non-HIV-infected subjects (P <0.05).

CONCLUSION

Putative periodontal pathogens are more prevalent in the subgingival microbiota of HIV-seronegative patients with chronic periodontitis, whereas species not usually associated with periodontitis are detected in higher frequency in HIV-seropositive subjects under HAART.

Bacterial diversity in necrotizing ulcerative periodontitis in HIV-positive subjects

BACKGROUND

Necrotizing ulcerative periodontitis (NUP) is a painful and potentially debilitating affliction that affects about 2% to 6% of HIV-positive subjects. NUP may be caused by specific microorganisms that are presently unknown or by microbial species not usually thought to cause periodontal infections. The purpose of this study was to define the bacterial species associated with NUP in HIV-positive patients.

METHODS

16S rRNA bacterial genes of DNA isolated from subgingival plaque of 8 HIV-positive subjects with NUP were amplified by polymerase chain reaction (PCR) and cloned into Escherichia coli. The sequences of cloned inserts were used to determine species identity or closest relatives by comparison with known sequences. The microbial profiles in subgingival plaque of subjects with NUP, chronic periodontitis, and periodontal health were compared using a battery of over 200 oligonucleotide probes in a PCR-based, reverse-capture, checkerboard DNA-DNA hybridization assay.

RESULTS

Sequence analysis of over 400 clones revealed 108 species; 65 were "uncultivable" phylotypes, of which 26 were novel to NUP subjects. Species or phylotypes most commonly detected were Bulleidia extructa, Dialister, Fusobacterium, Selenomonas, Peptostreptococcus, Veillonella, and the phylum TM7. Based on sequence analysis and checkerboard analysis, NUP did not possess the classical periodontal pathogens such as Porphyromonas gingivalis. Otherwise, the microbial profiles of NUP and periodontitis had many similarities. The microbial profiles of subgingival plaque from periodontally healthy subjects were different and less complex in comparison to the profiles of both disease groups.

CONCLUSIONS

Certain species appear to be associated with health and periodontal diseases. The putative pathogens associated with periodontal disease in HIV-negative subjects are not associated with NUP in HIV-positive subjects.

Association of T CD4 lymphocyte levels and subgingival microbiota of chronic periodontitis in HIV-infected Brazilians under HAART

OBJECTIVE

The aim of this study was to determine the subgingival microbiota of HIV-infected patients with chronic periodontitis and different T CD4 lymphocyte levels under HAART.

STUDY DESIGN

64 HIV+ patients (mean age 34.5 +/- 7.3; 75% males) were distributed into Group I: chronic periodontitis (> or = 3 sites with probing pocket depth (PPD) and/or clinical attachment level (CAL) > or = 5 mm); and Group II: periodontal health (no sites with PPD > 3 mm and/or CAL > 4 mm). All subjects received conventional periodontal therapy. Periodontal clinical parameters were evaluated at 6 sites/tooth in all teeth at baseline and 4 months after therapy. The levels of T CD4 were obtained from the patient's medical record. Subgingival plaque samples were taken from the 6 sites with the largest pocket depth in each subject of Group I, and 6 randomly selected sites in subjects of Group II. The presence of 22 subgingival species was determined using the checkerboard DNA-DNA hybridization method. Significant microbiological differences within and among groups were sought using Wilcoxon signed-rank and Mann-Whitney tests, respectively. Relationships between T CD4 levels and microbiological parameters were determined using Kruskal-Wallis test.

RESULTS

Sixty-one percent of the HIV-infected patients represented AIDS cases, although 69% of them were periodontally healthy. The T CD4 lymphocyte mean level was 333 cells/mm3 and viral load was 12,815 +/- 24,607 copies/mm3. Yet, the prevalence of chronic periodontitis was relatively low (36%). Several periodontal pathogens, in particular T. forsythensis (P < .05), were more prevalent in HIV-positive patients with periodontitis than in HIV-positive subjects with periodontal health. Most of the species decreased in frequency after therapy, particularly P. gingivalis (P < .05). E. faecalis and F. nucleatum were significantly more prevalent in the subgingival microbiota of patients with chronic periodontitis and lower levels of T CD4 (P < .05), while beneficial species tended to be more frequently detected in individuals with T CD4 counts over 500 cells/mm3.

CONCLUSION

The subgingival microbiota of HIV-infected patients with chronic periodontitis include a high prevalence of classical periodontal pathogens observed in non-infected individuals. Furthermore, the severe immunosuppression seems to favor the colonization by these species, as well as by species not commonly found in the subgingival microbiota.

Candida albicans secreted aspartyl proteinases in virulence and pathogenesis

Candida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known, in vitro, animal, and human studies have implicated the proteinases in C. albicans virulence in one of the following seven ways: (i) correlation between Sap production in vitro and Candida virulence, (ii) degradation of human proteins and structural analysis in determining Sap substrate specificity, (iii) association of Sap production with other virulence processes of C. albicans, (iv) Sap protein production and Sap immune responses in animal and human infections, (v) SAP gene expression during Candida infections, (vi) modulation of C. albicans virulence by aspartyl proteinase inhibitors, and (vii) the use of SAP-disrupted mutants to analyze C. albicans virulence. Sap proteins fulfill a number of specialized functions during the infective process, which include the simple role of digesting molecules for nutrient acquisition, digesting or distorting host cell membranes to facilitate adhesion and tissue invasion, and digesting cells and molecules of the host immune system to avoid or resist antimicrobial attack by the host. We have critically discussed the data relevant to each of these seven criteria, with specific emphasis on how this proteinase family could contribute to Candida virulence and pathogenesis.

Necrotizing stomatitis: report of 3 Pseudomonas aeruginosa-positive patients

Necrotizing oral lesions have been described in immunosuppressed patients, usually in association with gingival and periodontal pathoses. The etiology of these lesions has not been completely elucidated. We present 3 patients with a type of necrotizing stomatitis in which clinical patterns appear distinct from the periodontal forms of the disease. The lesions yielded bacterial cultures positive for Pseudomonas aeruginosa and reverted to no growth in 2 patients after proper antibiotic therapy. We propose that P aeruginosa may be responsible for selected necrotizing oral lesions with a clinical presentation lacking typical necrotizing periodontal disease and that this condition may represent the intraoral counterpart of ecthyma gangrenosum. In such cases, bacterial culture of the lesion becomes imperative because the disease does not respond to typical periodontal and antimicrobial therapy.

Periodontal pathogens in subgingival plaque of HIV-positive subjects with chronic periodontitis

Many putative periodontal pathogens associated with periodontal disease in human immunodeficiency virus (HIV)-infected patients also occur in non-HIV-infected individuals. This study examined the prevalence of eight periodontal pathogens in HIV-positive and HIV-negative patients with chronic periodontitis using the 16s RNA polymerase chain reaction technique. The results showed a significant prevalence of Porphyromonas gingivalis and Treponema denticola among HIV-negative patients compared to HIV-positive patients. Sixty percent of the patients in both groups were colonized by five to six species. Odds ratio analysis revealed a statistically significant positive association between three of the 28 possible combinations in the HIV-positive group. They included Prevotella nigrescens/Campylobacter rectus, P. nigrescens/P. gingivalis and P. nigrescens/T. denticola. Although the prevalence of periodontal pathogens is similar in both the groups, the combination of certain periodontal pathogens may be responsible for chronic periodontitis seen in HIV-infected adults.

A TEM/SEM study of the microbial plaque overlying the necrotic gingival papillae of HIV-seropositive, necrotizing ulcerative periodontitis

The purpose of this study was to examine by transmission (TEM) and scanning electron microscopy (SEM) the supragingival microbial plaque overlying the ulcerated gingival papillae of necrotizing ulcerative periodontitis (NUP) lesions in HIV-seropositive patients. The microbiota of NUP and HIV-seropositive patients with periodontitis has been reported to be similar to that of conventional periodontitis in non-infected subjects, although several investigators have also reported high recovery rates of microbes not generally associated with the indigenous oral microbial flora. Light and electron microscopic observations and microbial culture studies indicate a similar high prevalence of spirochetes in both necrotizing ulcerative gingivitis (NUG) and NUP. In addition, several studies have reported more frequent isolation of Candida albicans from diseased periodontal sites in HIV-seropositive patients than from non-diseased sites. Ten male and six female patients, each HIV-seropositive and exhibiting NUP, constituted the study population. Two biopsies of involved gingival papillae from between posterior teeth were obtained from each patient and processed for examination by both TEM and SEM. Microscopic examination revealed a surface biofilm comprised of a mixed microbial flora of various morphotypes in 81.3% of biopsy specimens. The subsurface flora featured dense aggregations of spirochetes in 87.5% of specimens. Zones of aggregated polymorphonuclear leukocytes and necrotic cells were also noted. Yeasts were observed in 65.6% of specimens and herpes-like viruses in 56.5% of the specimens. Collectively, except for the presence of yeast and viruses, the results suggest that the microbial flora and possibly the soft tissue lesions of NUP and necrotizing ulcerative gingivitis are very similar.

Oral treponemes and their outer membrane extracts activate human gingival epithelial cells through toll-like receptor 2

Oral treponemes are considered to be important in the development and progression of periodontal diseases. We investigated the mechanisms of recognition and activation of human gingival epithelial cells (HGEC) with the oral treponemes Treponema denticola, Treponema vincentii, and Treponema medium and their outer membrane extracts (OMEs). T. vincentii and T. medium but not T. denticola produced interleukin 8 (IL-8) in an HGEC culture. Further, all three treponemes induced IL-8 mRNA expression and NF-kappaB activation in HGEC. Among them, T. denticola especially exhibited trypsin- and chymotrypsin-like protease activities, and the addition of chymostatin, a chymotrypsin protease inhibitor, resulted in detectable IL-8 production by HGEC cultured with T. denticola. Additionally, IL-8 mRNA expression in HGEC cultured with the three treponemes and their OMEs was definitely inhibited by the mouse anti-human Toll-like receptor 2 (TLR2) monoclonal antibody TL2.1. These findings suggest that oral treponemes and their OMEs activate HGEC through TLR2.

Subgingival microbiota of renal transplant recipients

Renal transplant patients undergoing immunosuppressive therapy may experience periodontal side-effects such as gingival overgrowth. This study evaluated the subgingival microbiota of renal transplant recipients with or without periodontal tissue destruction who may have concurrent gingival enlargement. Subgingival paper point samples taken from the deepest probing sites of 38 subjects (one per patient) were examined using direct microscopy and culture techniques. A complex microflora comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes was observed using microscopy. Yeasts were occasionally detected. Significantly higher proportions of gram-positive morphotypes, including gram-positive cocci, were observed in samples from periodontally healthy patients. The predominant cultivable microflora from anaerobic culture comprised several species of facultative and obligate anaerobes. Colonization of the subgingival sites by 'foreign' microbes that are normally dermal, intestinal or vaginal flora was detected in up to 50% of the samples. High mean proportions of lost or unidentified species were also occasionally noted. The results showed that the subgingival biofilm of renal transplant recipients with chronic periodontitis comprised mainly gram-negative rods and spirochetes. Besides the usual predominant cultivable subgingival microbiota associated with periodontitis, the high prevalence of unidentified and 'foreign' microbes indicates the possibility of subgingival microbial alteration in renal transplant patients.

IgG subclass specific antibody response to periodontopathic organisms in HIV-positive patients

BACKGROUND

We previously reported an increased rate of progression of periodontal disease over an 18-month period in human immunodeficiency virus (HIV)-positive subjects compared to controls. The mechanism for disease progression and rapid tissue loss was unknown. Data on the microbiological studies failed to show any significant difference in the microbial characteristics of the periodontal lesions in HIV-positive patients compared to HIV-negative controls. Immunological analysis had identified neutrophils as an important component of the host defense against periodontal infection, especially against rapid tissue loss. Serum IgG reactivities to periodontal pathogens in HIV-positive patients with periodontitis were reduced. Other data provided circumstantial evidence to suggest that IgG subclass (IgG2) specific antibody might assist bacterial clearing in periodontal infection. The aim of the current study was to examine the specific IgG subclass antibody response to a panel of periodontopathic organisms: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella Intermedia (Pi), Fusobacterium nucleatum (Fn), Campylobacter rectus (Cr), and Bacteroides forsythus (Bf) in HIV-positive patients compared to HIV-negative controls.

METHODS

Sera from 120 HIV-positive patients (40 periodontitis, 69 gingivitis, and 11 no oral diseases) were tested for IgG subclass specific antibody response to the above listed 6 organisms using enzyme-linked immunosorbent assay. Data were compared with those obtained from 40 HIV-negative control subjects (35 periodontitis, 2 gingivitis, and 3 no oral diseases).

RESULTS

In the HIV-positive group, a consistently high response rate was found in IgG1 to all the bacteria tested. In addition, high levels of IgG3 and IgG4 to Pg and IgG1 and IgG2 to Pi were also present. However, no significant difference was detected among the periodontitis, gingivitis, and no oral disease subgroups. When the periodontitis patients from the HIV-positive group were compared to the HIV-negative group, no difference in the antibody levels and response rates was noted.

CONCLUSION

We conclude that in HIV-positive patients, the specific IgG subclass antibody response to periodontopathic organisms was similar to that of HIV-negative subjects.

An update on HIV and periodontal disease

With the advent of newer pharmacological approaches to the treatment of human immunodeficiency virus (HIV) infection, the incidence and progression of both atypical and conventional periodontal diseases are changing. The incidence of necrotizing periodontitis and gingival diseases of fungal origin appears to be on the decline as a result of these therapies that have led to increased life spans for HIV patients. However, in cases where these therapies lose their effectiveness and HIV patients relapse into an immunosuppressed state, these conditions may recur. Recent evidence has shown that HIV patients with more conventional periodontal diseases such as chronic periodontitis may have increased attachment loss and gingival recession when compared to their HIV-negative counterparts. This pattern of loss of periodontal support may be due in part to a diffuse invasion of opportunistic bacterial infections, viruses, and fungi into the gingival tissue, leading to a more elevated and more diffuse destructive inflammatory response in the periodontal soft and hard tissues. While the accepted approaches to treating the spectrum of periodontal diseases in HIV patients remain essentially unchanged over the past 15 years, the impact of newer systemic therapies on patient immunocompetence may influence treatment decisions.

Fungal infections associated with HIV infection

Oral candidiasis is perhaps the commonest infection seen in HIV disease. The aim of this workshop was to provide a sketch of the multifarious aspects of the disease from a global perspective. To this end the panellists addressed issues such as the virulence of Candida, emergence of antifungal resistance, management of candidiasis and other exotic, oral mycotic diseases. An all-pervasive theme was the dramatic differences in the management of fungal infections consequential to the availability (or the lack) of anti-HIV drugs in the developed and the developing world. Further, the social stigmata associated with the HIV disease in many developing regions in Africa and Asia appears to modify the therapeutic strategies. Additionally, the lesser-known regional variations in the disease manifestations and therapeutic approaches were stark. Further work is direly needed to address these issues.

Periodontal diseases and HIV infection

The workshop considered six related questions about periodontal changes seen in HIV infection. 1) To what extent are specific periodontal changes associated with HIV? 2) Are conventional periodontal diseases modified by HIV infection? The changes associated with HIV appear to be modified presentations of conventional diseases. Research should identify initiation and progression factors for necrotizing diseases. 3) What is the role of geography and transmission groups? These questions cannot be answered without greater standardisation of research methods. 4) Has the epidemiology of these changes changed with the advent of new therapies? The data required to answer this question should be available soon but this question is irrelevant to the vast majority of people with HIV. 5) What pathogens are involved in periodontal changes seen in HIV infection? The role of Candida spp. and other potential pathogens requires further investigation. 6) What management protocols are suitable for the periodontal diseases? The significance of periodontal diseases among people with HIV in developing countries is not known. Further research is needed of the effectiveness of interventions especially necrotizing disease in developing countries. The quality of research of these diseases would be enhanced by standardized approaches. A list of relevant variables might prevent their omission from studies.

Detection and quantification of oral treponemes in subgingival plaque by real-time PCR

Oral treponemes have been associated with periodontal diseases. We developed a highly sensitive and specific method to detect and quantify cultivable oral treponemes (Treponema denticola, Treponema vincentii, and Treponema medium) in 50 subgingival plaque samples from 13 healthy subjects as well as 37 patients with periodontal diseases using real-time PCR assays with specific primers and a TaqMan probe for each 16S rRNA sequence. The specificity for each assay was examined by using DNA specimens from various treponemal and other bacterial species. The TaqMan real-time PCR was able to detect from 10(3) to 10(8) cells of the oral treponemes, with correlation coefficients as follows: T. denticola, 0.984; T. vincentii, 0.991; and T. medium, 0.984. The frequencies of occurrence of these three oral treponemes in subgingival plaque samples were as follows: T. denticola, 68.0%; T. vincentii, 36.0%; and T. medium, 48.0%. In addition, the number of T. denticola, T. vincentii, and T. medium cells in plaque samples detected by real-time PCR ranged from 3 to 15,184, 1 to 447, and 1 to 7,301 cells/pg of plaque DNA, respectively. Increased numbers of T. denticola cells were detected in plaque samples from deep periodontal pockets, and T. medium was also detected in deep pockets. On the other hand, T. vincentii was mainly found in shallow pockets. These results suggest that various oral treponemes are associated with the formation of each stage of periodontal disease.

Differences in Candida albicans adhesion to intact and denatured type I collagen in vitro

An inhibition assay of Candida albicans adhesion to gelatin-immobilized membranes was compared with that to intact type I collagen-immobilized membranes using an arginine-glycine-aspartic acid (RGD) containing peptide. As compared with a protein-free membrane, gelatin and collagen significantly enhanced the adherence of C. albicans. The adhesion of the yeast to gelatin was significantly inhibited by the RGD peptides, but not by arginine-glycine-glutamic acid (RGE) peptides. In contrast, attachment to collagen was not inhibited by RGD peptides. These results suggest that the RGD sequence of gelatin and the integrin-like proteins of yeasts may be involved in adherence.

Role of glutathione metabolism of Treponema denticola in bacterial growth and virulence expression

Hydrogen sulfide (H(2)S) is a major metabolic end product detected in deep periodontal pockets that is produced by resident periodontopathic microbiota associated with the progression of periodontitis. Treponema denticola, a member of the subgingival biofilm at disease sites, produces cystalysin, an enzyme that catabolizes cysteine, releasing H(2)S. The metabolic pathway leading to H(2)S formation in periodontal pockets has not been determined. We used a variety of thiol compounds as substrates for T. denticola to produce H(2)S. Our results indicate that glutathione, a readily available thiol source in periodontal pockets, is a suitable substrate for H(2)S production by this microorganism. In addition to H(2)S, glutamate, glycine, ammonia, and pyruvate were metabolic end products of metabolism of glutathione. Cysteinyl glycine (Cys-Gly) was also catabolized by the bacteria, yielding glycine, H(2)S, ammonia, and pyruvate. However, purified cystalysin could not catalyze glutathione and Cys-Gly degradation in vitro. Moreover, the enzymatic activity(ies) in T. denticola responsible for glutathione breakdown was inactivated by trypsin or proteinase K, by heating (56 degrees C) and freezing (-20 degrees C), by sonication, and by exposure to N alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK). These treatments had no effect on degradation of cysteine by the purified enzyme. In this study we delineated an enzymatic pathway for glutathione metabolism in the oral spirochete T. denticola; our results suggest that glutathione metabolism plays a role in bacterial nutrition and potential virulence expression.

Recovery of Candida dubliniensis and other yeasts from human immunodeficiency virus-associated periodontal lesions

Oral and subgingival samples from periodontal lesions were collected from 54 human immunodeficiency virus (HIV)-positive and 20 HIV-negative patients and cultured for yeast species. Of the 54 samples cultured from HIV-positive patients, 44 (82%) were positive for yeast species, of which 29 (66%) were subgingival. A total of 19 (48%) patients were positive for Candida dubliniensis, of which 15 (79%) were colonized in subgingival sites. Seven isolates of Candida glabrata, two isolates of Candida parapsilosis, and one isolate of Saccharomyces cerevisiae were recovered. This study reports for the first time the recovery of C. dubliniensis from subgingival intraoral sites and confirms the presence of Candida species in sites of periodontal disease associated with HIV.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

Classifications of oral lesions in HIV infection

BACKGROUND

Manifestations of immunosuppression may take the form of opportunistic infection, and neoplasia. While this paper has focused on gingival and periodontal manifestations. these tissues cannot be evaluated in isolation. The presence of involvement of other oral tissues such as the cheek or tongue with manifestations associated with HIV such as hairy leukoplakia, Kaposi's sarcoma at these sites, and candidiasis in addition to periodontal manifestations may further increase the clincal suspicion of underlying immunosuppression and/or progression of the immunosuppressive state.

DISCUSSION

The periodontist plays an essential r le in identifying the periodontal status of an individual and has an important r le to play in early recognition of signs and symptoms of HIV disease or progression of the medical condition.

CONCLUSION

Only through such recognition can appropriate definitive diagnostic testing be conducted, and appropriate therapeutic intervention for the oral condition and the systemic condition be considered.