Distribution of biotypes and leukotoxic activity of Aggregatibacter actinomycetemcomitans isolated from Brazilian patients with chronic periodontitis

Evaluation of A. actinomycetemcomitans and P. gingivalis from the mouth of patients irradiated in the head and neck region: a cross-sectional study

PURPOSE

This study aimed to quantify Aggregatibacter actinomycetemcomitans (A.a) and Porphyromonas gingivalis (P.g) from the mouth of head and neck irradiated and cancer-free patients.

METHODS

Information such as age, presence of tongue coating, salivary flow, and biofilm were collected from head and neck irradiated patients (Group 1) and compared the results with a group of cancer-free individuals (Group 2). The presence of tongue coating was clinically examined. Sialometry was performed through a stimulating technique by chewing paraffin. Microbiological samples were collected from buccal and labial mucosa and tongue dorsum. Subsequently, the samples were processed and analyzed by qPCR to detect the presence and quantify the bacteria.

RESULTS

There was a statistical difference in the quantity of bacteria among the 24 individuals in Group 1 (A.a, 2817 ± 8718; P.g, 3145 ± 11297) and 26 individuals in Group 2 (A.a, 133996 ± 398545; P.g, 60 ± 195) regarding tongue coating (Group 1, A.a 2194.6 ± 4641.5; Group 2, A.a 92767.8 ± 333385.7) and salivary volume (Group 1, 0.69 mL; Group 2, 3.09 mL). The linear regression analysis found that the variable group was the main responsible for the difference in the quantity of periodontal pathogens (p-value < 0.001). There was no statistical difference in the amount of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis between totally edentulous and partially edentulous (with 12 or fewer teeth) patients.

CONCLUSION

Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were present in significant amounts in patients of both groups, with a greater quantity in cancer-free individuals.

Oleoresins and naturally occurring compounds of Copaifera genus as antibacterial and antivirulence agents against periodontal pathogens

Invasion of periodontal tissues by Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans can be associated with aggressive forms of periodontitis. Oleoresins from different copaifera species and their compounds display various pharmacological properties. The present study evaluates the antibacterial and antivirulence activity of oleoresins obtained from different copaifera species and of ten isolated compounds against two causative agents of periodontitis. The following assays were performed: determination of the minimum inhibitory concentration (MIC), determination of the minimum bactericidal concentration (MBC), and determination of the antibiofilm activity by inhibition of biofilm formation and biofilm eradication tests. The antivirulence activity was assessed by hemagglutination, P. gingivalis Arg-X and Lis-X cysteine protease inhibition assay, and A. actinomycetemcomitans leukotoxin inhibition assay. The MIC and MBC of the oleoresins and isolated compounds 1, 2, and 3 ranged from 1.59 to 50 μg/mL against P. gingivalis (ATCC 33277) and clinical isolates and from 6.25 to 400 μg/mL against A. actinomycetemcomitans (ATCC 43717) and clinical isolates. About the antibiofilm activity, the oleoresins and isolated compounds 1, 2, and 3 inhibited biofilm formation by at least 50% and eradicated pre-formed P. gingivalis and A. actinomycetemcomitans biofilms in the monospecies and multispecies modes. A promising activity concerning cysteine protease and leucotoxin inhibition was also evident. In addition, molecular docking analysis was performed. The investigated oleoresins and their compounds may play an important role in the search for novel sources of agents that can act against periodontal pathogens.

Chemokine Receptor 2 (CXCR2) Gene Variants and Their Association with Periodontal Bacteria in Patients with Chronic Periodontitis

Periodontitis, an inflammatory disease caused by subgingival Gram-negative (G-) bacteria, is linked with loss of the connective tissue and destruction of the alveolar bone. In the regulation of inflammatory response, chemokine receptor 2 (CXCR2), a specific receptor for interleukin-8 and neutrophil chemoattractant, plays an important role. The first aim of this study was to investigate the CXCR2 gene variability in chronic periodontitis (CP) patients and healthy nonperiodontitis controls in the Czech population. The second aim was to find a relation between CXCR2 gene variants and the presence of periodontal bacteria. A total of 500 unrelated subjects participated in this case-control study. 329 CP patients and 171 healthy nonperiodontitis controls were analyzed using polymerase chain reaction techniques for three single-nucleotide polymorphisms (SNPs): +785C/T (rs2230054), +1208T/C (rs1126579), and +1440A/G (rs1126580). A DNA microarray detection kit was used for the investigation of the subgingival bacterial colonization, in a subgroup of CP subjects (N = 162). No significant differences in allele, genotype, haplotype, or haplogenotype frequencies of CXCR2 gene variants between patients with CP and healthy controls (P > 0.05) were determined. Nevertheless, Aggregatibacter actinomycetemcomitans was detected more frequently in men positive for the C allele of the CXCR2 +785C/T polymorphism (61.8% vs. 41.1%, P < 0.05; OR = 2.31, 95% CI = 1.03-5.20) and for the T allele of the CXCR2 +1208C/T variant (61.8% vs. 38.9%, P < 0.05; OR = 2.54, 95% CI = 1.13-5.71). In contrast, no statistically significant associations of CXCR2 variants with seven selected periodontal bacteria were found in women. Although none of the investigated SNPs in the CXCR2 gene was associated with CP, the CXCR2 gene variants can be associated with subgingival colonization of G- bacteria in men with CP in the Czech population.

Periodontal pathogens and tetracycline resistance genes in subgingival biofilm of periodontally healthy and diseased Dominican adults

Objective

The objective of this study was to compare the periodontopathogen prevalence and tetracycline resistance genes in Dominican patients with different periodontal conditions.

Methods

Seventy-seven samples were collected from healthy, gingivitis, chronic (CP) and aggressive (AgP) periodontitis patients. Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Parvimonas micra, Eikenella corrodens and Dialister pneumosintes and 11 resistance genes were studied by PCR. P. gingivalis fimA genotype was determined.

Results

In healthy patients, P. micra and P. intermedia were the most and least frequently detected, respectively. T. forsythia and E. corrodens appeared in 100 % of gingivitis patients. Red complex, D. pneumosintes and E. corrodens were significantly more prevalent in CP compared to healthy patients. F. nucleatum and T. denticola were detected more frequently in AgP. A. actinomycetemcomitans was the most rarely observed in all groups. The fimA II genotype was the most prevalent in periodontitis patients. Seven tetracycline-resistant genes were detected. tet(Q), tet(32) and tet(W) showed the greatest prevalence. tet(32) was significantly more prevalent in CP than in healthy patients.

Conclusions

Red complex bacteria and D. pneumosintes were significantly the most prevalent species among periodontitis patients. T. forsythia was the most frequently detected in this population. To our knowledge, this is the first study describing the tet(32) gene in subgingival biofilm from healthy and periodontally diseased subjects.

Clinical relevance

This study contributes to the knowledge on the subgingival microbiota and its resistance genes of a scarcely studied world region. Knowing the prevalence of resistance genes could impact on their clinical prescription and could raise awareness to the appropriate use of antibiotics.

Electronic supplementary material

The online version of this article (doi:10.1007/s00784-015-1516-2) contains supplementary material, which is available to authorized users.

Microbiota associated with infections of the jaws

The microbial infections involving the craniofacial skeleton, particularly maxilla and mandible, have direct relationship with the dental biofilm, with predominance of obligate anaerobes. In some patients, these infections may spread to bone marrow or facial soft tissues, producing severe and life-threatening septic conditions. In such cases, local treatment associated with systemic antimicrobials should be used in order to eradicate the sources of contamination. This paper discuss the possibility of spread of these infections and their clinical implications for dentistry, as well as their etiology and aspects related to microbial virulence and pathogenesis.