Neutrophils in chronic and aggressive periodontitis in interaction with Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans

Background and Objective: This study analyzed the interaction of Porphyromonas gingivalis ATCC 33277 and Aggregatibacter actinomycetemcomitans Y4 with peripheral blood polymorphonuclear neutrophils taken from patients with aggressive periodontitis and chronic periodontitis. Material and Methods: Peripheral blood polymorphonuclear neutrophils obtained from 12 patients with chronic periodontitis, six patients with aggressive periodontitis and 12 healthy controls were exposed to P. gingivalis and A. actinomycetemcomitans following opsonization of the bacteria using the patient’s own serum. Serum immunoglobulin G (IgG) levels against both periodontopathogens were measured. Phagocytosis and killing of the bacteria, as well as the extracellular human neutrophil elastase activity, were quantified. The total amount and the extracellular release of reactive oxygen species were measured using luminol‐dependent and isoluminol‐dependent chemiluminescence. Results: Polymorphonuclear neutrophils from patients with chronic (62.16 ± 19.39%) and aggressive (43.26 ± 26.63%) periodontitis phagocytosed more P. gingivalis than the healthy controls (24.43 ± 19.87%) at the 30‐min time point after exposure to the bacteria (p < 0.05). High serum IgG levels against P. gingivalis and A. actinomycetemcomitans were detected in subjects with periodontitis. Polymorphonuclear neutrophils from subjects with chronic and aggressive periodontitis released significantly more reactive oxygen species and demonstrated greater human neutrophil elastase activity in the absence of any stimulus than polymorphonuclear neutrophils from healthy controls (p < 0.05). Polymorphonuclear neutrophils in chronic periodontitis released significantly more reactive oxygen species when exposed to P. gingivalis and A. actinomycetemcomitans than polymorphonuclear neutrophils in aggressive periodontitis. Conclusion: High serum IgG levels against P. gingivalis and A. actinomycetemcomitans promote phagocytosis in periodontitis. The extracellular release of reactive oxygen species and neutrophil elastase by polymorphonuclear neutrophils may also contribute to damage of the surrounding periodontal tissues.     

Prevalence of Aggregatibacter actinomycetemcomitans in Sudanese patients with aggressive periodontitis: a case-control study

Elamin A, Albandar JM, Poulsen K, Ali RW, Bakken V. Prevalence ofAggregatibacter actinomycetemcomitansin Sudanese patients with aggressive periodontitis: a case–control study. J Periodont Res 2011; 46: 285–291.©2011 John Wiley & Sons A/S Background and Objective: Aggregatibacter actinomycetemcomitans is considered a possible etiological agent for aggressive periodontitis. The aim of this study was to determine the prevalence of the JP2 clone and non‐JP2 genotypes of A. actinomycetemcomitans in the subgingival plaque of patients with aggressive periodontitis and controls among Sudanese high‐school students. Material and Methods: In a previous study we examined a large representative sample of students attending high schools in Khartoum, Sudan. In this population, 17 patients with aggressive periodontitis and 17 controls (14–19 years of age) consented to participate in the present study. The subjects underwent a clinical periodontal examination, and subgingival dental plaque samples were collected using paper points. The presence of the A. actinomycetemcomitans JP2 clone and non‐JP2 genotypes were assessed using loop‐mediated isothermal amplification (LAMP) and the PCR. Results: The JP2 clone of A. actinomycetemcomitans was not detected in the subgingival plaque of either the cases or the controls. Non‐JP2 types of A. actinomycetemcomitans were detected in the subgingival plaque of 12 (70.6%) patients with aggressive periodontitis and from only one (5.9%) control subject, showing a significantly higher frequency of detection in cases than in controls (p = 0.0001). The odds ratio for the detection of A. actinomycetemcomitans in the subgingival plaque of the patients with aggressive periodontitis was 38.4 (95% confidence interval: 4.0–373.0; p = 0.002). The PCR and LAMP methods showed identical results pertaining to the identification of non‐JP2 types of A. actinomycetemcomitans. Conclusions: The JP2 clone of A. actinomycetemcomitans was not detected in the subgingival plaque of high school subjects in Sudan. The detection of non‐JP2 types of A. actinomycetemcomitans may be a useful marker of increased risk for development of aggressive periodontitis in young subjects.     

Detection rates of presumptive periodontal pathogens in subgingival plaque samples of untreated periodontitis using either four or six pooled samples

Aim: A comparison of the detection frequency and number of periodontal pathogens in patients with aggressive or generalized, severe chronic periodontitis using a gene‐probe analysis. Methods: In 16 aggressive and 34 generalized, severe chronic periodontitis patients, plaque was sampled from the deepest pockets per quadrant (MT4) and per sextant (MT6). After sampling two paper points simultaneously, one paper point from each pocket was pooled with three paper points of the other pockets (MT4). The remaining four paper points were pooled with two paper points from the deepest pockets from the two remaining sextants (MT6). Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola were detected by 16S rRNA gene probes. Results: Log‐transformed counts for Aggregatibacter actinomycetemcomitans were statistically significantly higher with MT6 (aggressive: 3.21 ± 2.94; generalized, severe chronic: 2.22 ± 2.70) than MT4 (aggressive: 2.04 ± 2.74; generalized, severe chronic: 1.50 ± 2.37) (P < 0.05). The detection frequency and mean counts were high for Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola (>95%/>6.0). Conclusion: Aggregatibacter actinomycetemcomitans was detected in higher numbers for MT6 than MT4. For both MT4 and MT6, Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola were detected in >95% of all patients and with mean log‐transformed numbers >6.0.     

Quantitative real-time polymerase chain reaction versus culture: a comparison between two methods for the detection and quantification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in subgingival plaque samples

OBJECTIVE: The purpose of this investigation was to validate a real-time quantitative polymerase chain reaction (PCR) assay in identifying and quantifying Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis from subgingival plaque samples taken from subjects with different periodontal conditions, when compared with conventional cultural procedures. PATIENTS AND METHODS: Ninety-two adult subjects participated in this study, 32 with periodontitis, 30 with gingivitis and 30 healthy. A pooled subgingival sample was obtained from every patient. Culturing procedures were carried out using standard techniques. For real-time PCR analysis, primers were selected from sequences of the LktC (A. actinomycetemcomitans), Arg-gingipain (P. gingivalis) and BspA antigen (T. forsythensis) genes. Contingency tables were constructed to compare the qualitative results, while quantitative data were evaluated by paired t-test. RESULTS: A. actinomycetemcomitans was the least frequently recovered species with both techniques. Prevalence of P. gingivalis was low in healthy patients, increased in gingivitis and peaked in periodontitis patients. The frequency of detection of T. forsythensis showed marked differences between culture and PCR, although the same tendency of an increase in prevalence from health to gingivitis and to periodontitis was observed with both methods. Contingency tables demonstrated a good level of agreement between PCR and culture procedures for A. actinomycetemcomitans and P. gingivalis, especially in periodontitis patients. P. gingivalis culture counts were significantly higher than those obtained by PCR. The opposite was true for T. forsythensis, and statistically significant higher counts were obtained by PCR for gingivitis and periodontitis patients. CONCLUSION: This study demonstrated a good agreement between the quantitative PCR technology and the culture procedure. The high sensitivity and specificity of the quantitative PCR technology justify its use in epidemiological studies and as an adjunct in clinical diagnosis of periodontal patients.     

实时荧光定量PCR检测牙周炎患者龈下菌斑的分布

目的 应用实时荧光定量PCR技术探索侵袭性牙周炎（aggressive periodontitis,AgP）、慢性牙周炎（chronic periodontitis,CP）患者龈下菌斑中伴放线聚集杆菌(A. actinomycetemcomitans,Aa)、牙龈卟啉单胞菌（P. gingivalis,Pg）的分布规律。方法 采集32例AgP、33例CP、32例牙周健康者的龈下菌斑,构建含有2种待测细菌基因片段的重组质粒,建立定量标准,采用TaqManMGB探针实时荧光定量PCR方法检测样本中细菌数量。结果 本实验构建的引物及TaqManMGB探针特异性及敏感性较好。AgP组龈下菌斑Aa的检出率高于CP组（P＜0.01）,但2种细菌数量在组间无显著差异,两组内Pg的检出率及数量都明显高于Aa（P＜0.001）,另外AgP组Aa的数量、CP组Pg数量与牙周探诊深度密切相关（P＜0.01及P＜0.001）。结论 龈下菌斑Aa的检出率可能与牙周炎类型存在一定关联,Aa可能并不是中国人群样本AgP患者龈下菌斑的优势菌,实时荧光定量PCR对牙周病学研究有广泛应用前景。     

Carpegen® real‐time polymerase chain reaction vs. anaerobic culture for periodontal pathogen identification

Background/aims: The aim of this study was to compare two methods of microbiological diagnosis, anaerobic bacterial culture and real‐time polymerase chain reaction (PCR), for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, and Treponema denticola. Methods: Seventy‐two samples were collected from 18 patients who were suffering from aggressive periodontitis. The data obtained were compared for the two methods. Results: The results obtained with real‐time PCR were different from those obtained with bacterial culture. The detection differences were 3% for A. actinomycetemcomitans, 8.33% for P. intermedia, and 12.5% for F. nucleatum. However, the differences for P. gingivalis and T. forsythia were 51.39% and 36.11%, respectively. No comparison was possible for T. denticola because it cannot be identified in culture. The variations found were the result of the better detection level (10² pathogens) of the PCR probe. Unlike bacterial culture, PCR allows the detection of T. denticola, which does not forming colonies and is oxygen sensitive. For F. nucleatum, T. forsythia and P. gingivalis, the real‐time PCR technique was more sensitive than culture. Conclusion: Good results were obtained with the real‐time PCR technique for the six periopathogens targeted. This method seems to be indicated for its simplicity, rapidity and reproducibility but it cannot analyze data for an antibiotic susceptibility test. The periodontist must therefore choose one of these two methods according to his specific clinical objective: to obtain rapid, specific detection even with weak initial concentrations (but for targeted periopathogens only) or to be non‐specific and analyze the pathological activity with an antibiogram.