Association of Filifactor alocis and its RTX toxin gene ftxA with periodontal attachment loss, and in synergy with Aggregatibacter actinomycetemcomitans.

The Gram-positive bacterium, Filifactor alocis is an oral pathogen, and approximately 50% of known strains encode a recently identified repeat-in-toxin (RTX) protein, FtxA. By assessing a longitudinal Ghanaian study population of adolescents (10-19 years of age; mean age 13.2 years), we recently discovered a possible correlation between deep periodontal pockets measured at the two-year follow-up, presence of the ftxA gene, and a high quantity of F. alocis. To further understand the contribution of F. alocis and FtxA in periodontal disease, we used qPCR in the present study to assess the carriage loads of F. alocis and the prevalence of its ftxA gene in subgingival plaque specimens, sampled at baseline from the Ghanaian cohort (n=500). Comparing these results with the recorded clinical attachment loss (CAL) longitudinal progression data from the two-year follow up, we concluded that carriers of ftxA-positive F. alocis typically exhibited higher loads of the bacterium. Moreover, high carriage loads of F. alocis and concomitant presence of the ftxA gene were two factors that were both associated with an enhanced prevalence of CAL progression. Interestingly, CAL progression appeared to be further promoted upon the simultaneous presence of F. alocis and the non-JP2 genotype of Aggregatibacter actinomycetemcomitans. Taken together, our present findings are consistent with the notion that F. alocis and its ftxA gene promotes CAL during periodontal disease.

Aggregatibacter actinomycetemcomitans and Filifactor alocis as Associated with Periodontal Attachment Loss in a Cohort of Ghanaian Adolescents.

The aims of the present study were to document the presence of Aggregatibacter actinomyctemcomitans and the emerging oral pathogen Filifactor alocis, as well as to identify genotypes of these bacterial species with enhanced virulence. In addition, these data were analyzed in relation to periodontal pocket depth (PPD) and the progression of PPD from the sampled periodontal sites during a two-year period. Subgingival plaque samples were collected from 172 periodontal pockets of 68 Ghanaian adolescents. PPD at sampling varied from 3-14 mm and the progression from baseline, i.e., two years earlier up to 8 mm. The levels of A. actinomycetemcomitans and F. alocis were determined with quantitative PCR. The highly leukotoxic JP2-genotype of A. actinomycetemcomitans and the ftxA a gene of F. alocis, encoding a putative Repeats-in-Toxin (RTX) protein, were detected with conventional PCR. The prevalence of A. actinomycetemcomitans was 57%, and 14% of the samples contained the JP2 genotype. F. alocis was detected in 92% of the samples and the ftxA gene in 52%. The levels of these bacterial species were significantly associated with enhanced PPD and progression, with a more pronounced impact in sites positive for the JP2 genotype or the ftxA gene. Taken together, the results indicate that the presence of both A. actinomycetemcomitans and F. alocis with their RTX proteins are linked to increased PPD and progression of disease.

Screening at the dental office: An opportunity for bridging the gap in the early diagnosis of hypertension and diabetes in Ghana.

Background: The prevalence of hypertension and diabetes is increasing in Ghana and sub-Saharan Africa. Screening is a useful tool in improving the early detection of both diseases to reduce the mortality and morbidity associated with the conditions. This study set out to determine the prevalence of patients with hypertension and hyperglycemia attending a dental clinic in Accra. Methods: A cross-sectional study, modeling a screening exercise, was conducted in a major dental clinic in Accra. Hypertension and diabetes were screened for with serial blood pressure checks at rest and random blood glucose measurements, respectively. Other variables were the pulse rate, the respiratory rate, and the background characteristics of respondents. Data were analyzed with Stata Version 14, and descriptive statistics were generated and reported. Results: There were a total of 175 participants in the study, comprising 76 males (43.4%) and 99 females (56.6%). This represented a male-to-female ratio of 0.8:1. The ages ranged from 18 to 86 years, with the median and mean ages of 40 years and 43.1 years (±16.9), respectively. This study found the prevalence of hypertension and hyperglycemia i the dental clinic to be 31.4% and 24.6%, respectively. Conclusion: The results of this study demonstrate the importance of the dental clinic in detecting both undiagnosed hypertension and diabetes, as well as those who have previously been diagnosed, but do not have their blood pressure and blood sugar under adequate control. With efficient referrals and follow-up systems in place at dental offices, they could be harnessed as a fertile place for hypertension and diabetes screening.

RésuméContexte: La prévalence de l'hypertension et du diabète augmente au Ghana et en Afrique subsaharienne. Le dépistage est un outil utile pour améliorer la détection précoce des deux maladies afin de réduire la mortalité et la morbidité associées à ces affections. Cette étude visait à déterminer la prévalence de l'hypertension et de l'hyperglycémie chez les patients fréquentant une clinique dentaire à Accra. Méthodes: Une étude transversale, modélisant un exercice de dépistage, a été menée dans une grande clinique dentaire à Accra. L'hypertension artérielle et le diabète ont fait l'objet d'un dépistage au moyen d'une vérification sérielle de la tension artérielle au repos et de mesures aléatoires de la glycémie, respectivement. Les autres variables étaient le pouls, la fréquence respiratoire et les caractéristiques de base des répondants. Les données ont été analysées à l'aide de la version 14 de Stata, et des statistiques descriptives ont été produites et présentées. Résultats: Au total, 175 participants ont participé à l'étude, dont 76 hommes (43,4 %) et 99 femmes (56,6 %). Cela représentait un ratio hommes/femmes de 0,8:1. L'âge variait de 18 à 86 ans, l'âge médian et l'âge moyen étant respectivement de 40 ans et 43,1 ans (±16,9 ans). Cette étude a révélé que la prévalence de l'hypertension et de l'hyperglycémie à la clinique dentaire était de 31,4 % et 24,6 %, respectivement. Conclusion: Les résultats de cette étude démontrent l'importance de la clinique dentaire dans la détection de l'hypertension et du diabète non diagnostiqués, ainsi que de ceux qui ont déjà reçu un diagnostic, mais dont la tension artérielle et la glycémie ne sont pas sous contrôle adéquat. Avec des références efficaces et des systèmes de suivi en place dans les cabinets dentaires, ils pourraient être exploités comme un lieu fertile pour le dépistage de l'hypertension et du diabète.

High salivary levels of JP2 genotype of Aggregatibacter actinomycetemcomitans is associated with clinical attachment loss in Moroccan adolescents.

It has previously been shown that the presence of Aggregatibacter actinomycetemcomitans in subgingival plaque is significantly associated with increased risk for clinical attachment loss. The highly leukotoxic JP2 genotype of this bacterium is frequently detected in adolescents with aggressive forms of periodontitis. The aims of the study were to quantify the levels of JP2 and non-JP2 genotypes of A. actinomycetemcomitans in saliva of Moroccan adolescents with the JP2 genotype earlier detected in the subgingival plaque. The salivary concentrations of inflammatory proteins were quantified and linked to the clinical parameters and microbial findings. Finally, a mouth rinse with leukotoxin-neutralizing effect was administrated and its effect on the levels the biomarkers and A. actinomycetemcomitans examined. The study population consisted of 22 adolescents that previously were found to be positive for the JP2 genotype in subgingival plaque. Periodontal registration and sampling of stimulated saliva was performed at baseline. A mouth rinse (active/placebo) was administrated, and saliva sampling repeated after 2 and 4 weeks rinse. The salivary levels of JP2 and non-JP2 were analyzed by quantitative PCR and inflammatory proteins by ELISA. Both the JP2 and the non-JP2 genotype were detected in all individuals with significantly higher levels of the non-JP2. Enhanced levels of the JP2 genotype of A. actinomycetemcomitans was significantly correlated to the presence of attachment loss (≥3 mm). Salivary concentrations of inflammatory biomarkers did not correlate to periodontal condition or levels of A. actinomycetemcomitans. The use of active or placebo leukotoxin-neutralizing mouth rinse did not significantly interfered with the levels of these biomarkers. Saliva is an excellent source for detection of A. actinomycetemcomitans on individual basis, and high levels of the JP2 genotype were significantly associated with the presence of clinical attachment loss.

Leukotoxic activity of Aggregatibacter actinomycetemcomitans and periodontal attachment loss.

Aggregatibacter actinomycetemcomitans is a Gram-negative periodontitis-associated bacterium that expresses a toxin that selectively affects leukocytes. This leukotoxin is encoded by an operon belonging to the core genome of this bacterial species. Variations in the expression of the leukotoxin have been reported, and a well-characterized specific clonal type (JP2) of this bacterium with enhanced leukotoxin expression has been isolated. In particular, the presence of the JP2 genotype significantly increases the risk for the progression of periodontal attachment loss (AL). Based on these findings we hypothesized that variations in the leukotoxicity are linked to disease progression in infected individuals. In the present study, the leukotoxicity of 239 clinical isolates of A. actinomycetemcomitans was analysed with different bioassays, and the genetic peculiarities of the isolates were related to their leukotoxicity based on examination with molecular techniques. The periodontal status of the individuals sampled for the presence of A. actinomycetemcomitans was examined longitudinally, and the importance of the observed variations in leukotoxicity was evaluated in relation to disease progression. Our data show that high leukotoxicity correlates with an enhanced risk for the progression of AL. The JP2 genotype isolates were all highly leukotoxic, while the isolates with an intact leukotoxin promoter (non-JP2 genotypes) showed substantial variation in leukotoxicity. Genetic characterization of the non-JP2 genotype isolates indicated the presence of highly leukotoxic genotypes of serotype b with similarities to the JP2 genotype. Based on these results, we conclude that A. actinomycetemcomitans harbours other highly virulent genotypes besides the previously described JP2 genotype. In addition, the results from the present study further highlight the importance of the leukotoxin as a key virulence factor in aggressive forms of periodontitis.

Subgingival bacteria in Ghanaian adolescents with or without progression of attachment loss.

OBJECTIVE: This study describes subgingival bacterial profiles associated with clinical periodontal status in Ghanaian adolescents with or without progression of attachment loss. MATERIALS AND METHODS: Among 500 adolescents included in a cohort study, 397 returned 2 years later for a periodontal re-examination, including full-mouth CAL measurements. At follow-up, a subgroup of 98 adolescents was also subjected to bacterial sampling with paper points at four periodontal sites (mesial aspect of 11, 26, 31, and 46) and analyzed with the checkerboard DNA-DNA hybridization technique against DNA-probes from nine periodontitis-associated bacterial species. RESULTS: The 98 Ghanaian adolescents examined in the present study were similar to the entire group examined at the 2-year follow-up with respect to age, gender, and CAL ≥3 mm. A high detection frequency of Fusobacterium nucleatum and Prevotella intermedia (>99%) using checkerboard analysis was found, while for Aggregatibacter actinomycetemcomitans the detection frequency was <50%. A strong correlation was found at the individual level between the presence of P. intermedia and the total CAL change, and P. intermedia and Porphyromonas gingivalis were strongly correlated with a change in CAL and probing pocket depth (PPD) at the sampled sites. In a linear regression model, a significant discriminating factor for the total CAL change in the dentition during the 2-year follow-up period was obtained for P. intermedia and public school. CONCLUSION: This study indicates that subgingival bacterial species other than A. actinomycetemcomitans, for example, P. intermedia, have a significant association with periodontal breakdown (change in CAL) in Ghanaian adolescents with progression of periodontal attachment loss.

Progression of attachment loss is strongly associated with presence of the JP2 genotype of Aggregatibacter actinomycetemcomitans: a prospective cohort study of a young adolescent population.

AIM: To assess the progression of attachment loss (AL) during a 2-year period according to the presence of JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans in a Ghanaian adolescent population. METHODS: A total of 500 adolescents (mean age 13.2 years, SD ± 1.5) were enrolled in the study. After 2 years, 397 (79.4%) returned for a periodontal re-examination, including the measurement of AL. The carrier status of the JP2 and non-JP2 genotypes of A. actinomycetemcomitans was evaluated in a baseline examination 2 years earlier. RESULTS: Individuals who carried the JP2 genotype of A. actinomycetemcomitans had a significantly increased risk [relative risk (RR) = 7.3] of developing AL ≥ 3 mm. The mean AL at the follow-up and the mean 2-year progression of AL were significantly higher in the JP2 genotype-positive group (n = 38) compared with the group positive for the non-JP2 genotypes of A. actinomycetemcomitans (n = 169), and the group of A. actinomycetemcomitans-negative individuals (n = 190). The JP2 genotype was strongly associated with the progression of AL ≥ 3 mm (OR = 14.3). The non-JP2 genotypes of A. actinomycetemcomitans were also, however, less pronounced, associated with the progression of AL ≥ 3 mm (OR = 3.4). CONCLUSION: The JP2 genotype of A. actinomycetemcomitans is strongly associated with the progression of AL.

Cytolethal distending toxin in isolates of Aggregatibacter actinomycetemcomitans from Ghanaian adolescents and association with serotype and disease progression.

BACKGROUND AND OBJECTIVES: The cytolethal distending toxin (Cdt) is a highly conserved exotoxin that are produced by a number of Gram negative bacteria, including Aggregatibacter actinomycetemcomitans, and affects mammalian cells by inhibiting cell division and causing apoptosis. A complete cdt-operon is present in the majority of A. actinomycetemcomitans, but the proportion of isolates that lack cdt-encoding genes (A, B and C) varies according to the population studied. The objectives of this study were to examine serotype, Cdt-genotype, and Cdt-activity in isolates of A. actinomycetemcomitans collected from an adolescent West African population and to examine the association between the carrier status of A. actinomycetemcomitans and the progression of attachment loss (AL). MATERIALS AND METHODS: A total of 249 A. actinomycetemcomitans isolates from 200 Ghanaian adolescents were examined for serotype and cdt-genotype by PCR. The activity of the Cdt-toxin was examined by DNA-staining of exposed cultured cells and documented with flow cytometry. The periodontal status of the participants was examined at baseline and at a two-year follow-up. RESULTS: Presence of all three cdt-encoding genes was detected in 79% of the examined A. actinomycetemcomitans isolates. All these isolates showed a substantial Cdt-activity. The two different cdt-genotypes (with and without presence of all three cdt-encoding genes) showed a serotype-dependent distribution pattern. Presence of A. actinomycetemcomitans was significantly associated with progression of AL (OR = 5.126; 95% CI = [2.994-8.779], p<0.001). CONCLUSION: A. actinomycetemcomitans isolated from the Ghanaian adolescents showed a distribution of serotype and cdt-genotype in line with results based on other previously studied populations. Presence of A. actinomycetemcomitans was significantly associated with disease progression, in particular the b serotype, whereas the association with disease progression was not particularly related to cdt-genotype, and Cdt-activity.

Distribution of Candida species among HIV-positive patients with oropharyngeal candidiasis in Accra, Ghana.

INTRODUCTION: Oropharyngeal candidiasis is a common occurrence in the course of human immunodeficiency virus (HIV) disease progression. Changes in the clinical severity of oropharyngeal candidiasis and type of Candida species profile may be a reflection of immunological changes in patients. The aim of this study was to undertake a baseline Candida species identification for future reference. METHODOLOGY: Oral swabs of 267 HIV-infected patients with oropharyngeal candidiasis were cultured and Candida species were identified by API 32 C. RESULTS: A total of 201 (75.3%) Candida species and 10 (3.7%) non candida fungi were identified. Twenty different Candida species were isolated. Candida albicans was the most prevalent species (68.5%) followed by C. tropicalis (7.4%), C. krusei (6.4%), C. parapsilosis (3.0%) and C. sake (2.5%). Other species ranged from 0.5% to 1.5%. Positive culture was independent of whether patients were on anti-retroviral therapy or not. CONCLUSION: Of all Candida isolates, 68.5% were identified as C. albicans. Since other uncommon species were also isolated, it may be necessary in this group of patients to identify Candida species causing severe infections.

Distribution of Candida Species among HIV-Positive Patients with Oropharyngeal Candidiasis in Accra; Ghana

Introduction: Oropharyngeal candidiasis is a common occurrence in the course of human immunodeficiency virus (HIV) disease progression. Changes in the clinical severity of oropharyngeal candidiasis and type of Candida species profile may be a reflection of immunological changes in patients. The aim of this study was to undertake a baseline Candida species identification for future reference. Methodology: Oral swabs of 267 HIV-infected patients with oropharyngeal candidiasis were cultured and Candida species were identified by API 32 C. Results: A total of 201 (75.3) Candida species and 10 (3.7) non candida fungi were identified. Twenty different Candida species were isolated. Candida albicans was the most prevalent species (68.5) followed by C. tropicalis (7.4); C. krusei (6.4); C. parapsilosis (3.0) and C. sake (2.5). Other species ranged from 0.5 to 1.5.Positive culture was independent of whether patients were on anti-retroviral therapy or not. Conclusion: of all Candida isolates; 68.5 were identified as C. albicans. Since other uncommon species were also isolated; it may be necessary in this group of patients to identify Candida species causing severe infections

Interactions of extracts from selected chewing stick sources with Aggregatibacter actinomycetemcomitans.

BACKGROUND: Aggregatibacter actinomycetemcomitans produces a leukotoxin that activates a pro-inflammatory death of human monocytes/macrophages. A specific clone of this bacterium (JP2) has a 530-base pair deletion in the leukotoxin promoter gene and significantly enhanced expression of leukotoxin. This specific clone of A. actinomycetemcomitans is common in some African populations and has a strong association with periodontal attachment loss in adolescents in these populations. Chewing sticks of plant origin are commonly used as oral hygiene tool in Africa, but their role as a therapeutic agent in periodontal disease is poorly investigated. RESULTS: Ethanol extracts were made from 7 common plants used as chewing sticks in West-Africa. None of the tested extracts inhibited growth of A. actinomycetemcomitans. However, extracts from Psidium guajava (Guava) completely neutralized the cell death and pro-inflammatory response of human leukocytes induced by the leukotoxin. None of the six other tested chewing stick extracts showed this effect. CONCLUSIONS: The discovery that extracts from Guava efficiently neutralizes A. actinomycetemcomitans leukotoxicity might lead to novel therapeutic agents and strategies for prevention and treatment of aggressive forms of periodontitis induced by infections with the highly leukotoxic JP2 clone of this bacterium.

Presence of JP2 and Non-JP2 Genotypes of Aggregatibacter actinomycetemcomitans and attachment loss in adolescents in Ghana.

BACKGROUND: Limited data are reported concerning the presence of A. actinomycetemcomitans and attachment loss (AL) in sub-Saharan countries. The authors investigate the carrier frequency of JP2 and non-JP2 genotypes of A. actinomycetemcomitans and the presence of AL in Ghanaian adolescents and evaluate socioeconomic conditions and oral hygiene practices. METHODS: Five hundred individuals (mean ± SD age: 13.2 ± 1.5 years) in public and private schools were interviewed about demographic characteristics and oral hygiene practices and were given a full-mouth periodontal examination. Subgingival plaque samples were obtained from periodontal sites around permanent first molars and incisors. The carrier status of A. actinomycetemcomitans at the individual level was determined based on results obtained by cultivation and polymerase chain reaction. RESULTS: The findings of this study show a relatively high carrier rate of JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans in the Ghanaian adolescent population and the presence of this bacterium is associated with the occurrence of AL. The overall carrier rate of A. actinomycetemcomitans was 54.4%, and the highly leukotoxic JP2 genotype was detected in 8.8% of the study population. A total of 107 (21.4%) individuals had ≥ 1 tooth with AL ≥ 3 mm. The majority of the individuals carrying A. actinomycetemcomitans (80.1%) (P <0.001) and of the periodontally diseased individuals (91.6%) (P <0.001) were found in public schools. CONCLUSIONS: A. actinomycetemcomitans and AL were frequently found in Ghanaian adolescents. The school type was the strongest predictor of both presence of A. actinomycetemcomitans and AL.