不同fimA基因型牙龈卟啉单胞菌在慢性牙周炎患者中的分布

目的　分析不同fimA基因型牙龈卟啉单胞菌(P.gingivalis)在慢性牙周炎患者中的分布状况。方法　收集101例慢性牙周炎患者的龈下菌斑,采用常规培养法和16S rRNA PCR检测P.gingivalis,并根据各fimA基因型的特异引物,用聚合酶链反应(PCR)检测不同fimA基因型菌株的分布。结果　16S rRNA PCR检测P.gingivalis阳性检出率为88·1%。大多数受检牙龈下菌斑中只检测出一种fimA基因型菌株(65·1%),各fimA基因型的总检出率: ⅠfimA为24·7%;ⅡfimA为43·8%;ⅢfimA为15·7%;ⅣfimA为40·4%;VfimA为3·4%。结论　慢性牙周炎患者龈下菌斑中的牙龈卟啉单胞菌存在fimA基因多态性,ⅡfimA和ⅣfimA基因型P.gingivalis菌株与慢性牙周炎的发生发展关系密切。     

The prevalence and pathogenic differences of Porphyromonas gingivalis fimA genotypes in patients with aggressive periodontitis

BACKGROUND: The fimA gene, which encodes fimbrillin (FimA), is found in Porphyromonas gingivalis and has been classified into six genotypes based on nucleotide sequence. P. gingivalis that possesses the type II fimA gene is prevalent in adult periodontitis. OBJECTIVES: The aim of this study was to investigate the prevalence of P. gingivalis fimA genotypes in Japanese aggressive periodontitis patients, and to examine their virulence. METHODS: Subgingival plaque samples were obtained from 223 sites in 18 aggressive periodontitis patients and 95 sites in 22 periodontally healthy young adults. Actinobacillus actinomycetemcomitans, P. gingivalis and Tannerella forsythensis detection, determination of the fimA genotype in P. gingivalis, and the quantification of P. gingivalis were analyzed by polymerase chain reaction (PCR) methods. The proteolytic activities of the P. gingivalis fimA type I and fimA type II were also examined. RESULTS: In aggressive periodontitis patients, the most prevalent fimA genotype was the type II (46.7%), followed by the type Ib and type I, whereas in healthy subjects, the type I fimA was the only genotype detected. The number of P. gingivalis pathogens was the greatest in the type I fimA positive sites, and the frequency of coexisting A. actinomycetemcomitans and T. forsythensis was highest in the type II fimA positive sites in the aggressive periodontitis patients. Both the arginine-specific cysteine proteinase (Arg-gingipain) and lysine-specific cysteine proteinase (Lys-gingipain) activity of the P. gingivalis fimA type I strain were significantly higher than those of the fimA type II strains. CONCLUSIONS: These results suggest that differences in virulence exist among different fimA genotypes. Coadherence with other pathogens in P. gingivalis fimA type II-associated aggressive periodontitis and quantitative increases in P. gingivalis in fimA type I-associated aggressive periodontitis are related to this virulence.     

牙龈卟啉单胞菌与牙周基础治疗关系的实验研究

目的应用TaqMan实时荧光定量聚合酶链反应法检测慢性牙周炎患者牙周洁刮治术（SRP）治疗前后龈下菌斑中牙龈卟啉单胞菌（P. gingivalis）的变化,分析P. gingivalis与SRP疗效之间的关系,探讨应用实时荧光定量聚合酶链反应监测和评价SRP的可能性。方法选择20例中重度慢性牙周炎患者为研究对象,检查SRP治疗前后的临床指标,包括探诊深度（PD）、临床附着丧失（CAL）和探诊出血（BOP）;采集SRP治疗前后的龈下菌斑共142个样本,应用TaqMan实时荧光定量聚合酶链反应检测样本中的P. gingivalis。构建含有P. gingivalis扩增片段的重组质粒,建立定量标准。结果慢性牙周炎患者SRP治疗后PD、CAL和BOP均明显下降（P<0.001）;治疗前P. gingivalis检出率为80.28%,治疗后下降为54.23%;治疗前P. gingivalis数量与PD相关,Kendall相关系数为0.70（P<0.001）,治疗后牙周袋内细菌数量明显减少（P<0.001）。治疗前牙周袋内P. gingivalis的定植数量与PD、CAL和BOP的改善无相关性（P>0.05）,但治疗后治疗有效位点P. gingivalis数量减少程度明显大于治疗无效位点（P<0.05）,细菌减少量与PD改善弱相关（r=0.25,P=0.04）。结论SRP治疗可以明显改善临床症状,降低P. gingivalis检出率和绝对数量;治疗前P. gingivalis定植水平对临床指标的改善没有影响,治疗后P. gingivalis数量下降程度可以反映治疗效果。TaqMan实时荧光定量聚合酶链反应可以用于牙周炎治疗效果的监测和评价。     

Prevalence of Porphyromonas gingivalis in relation to periodontal status assessed by real-time PCR

Many studies have examined the presence of Porphyromonas gingivalis in periodontal pockets. However, monitoring the number of bacterial cells is difficult. In this study, we performed quantitative analyses of P. gingivalis to clarify the relationship between the numbers of this organism and periodontal status. Using the TaqMan real-time PCR system, we found a significant positive correlation (P < 0.0001) between the number of P. gingivalis and pocket depth. The slope of the regression line indicated that for every 1-mm increase in pocket depth, the number of P. gingivalis increased 10- fold. There was also a significant reduction (P < 0.01) in the numbers of P. gingivalis before and after treatment. These results suggest that the absolute and relative numbers of P. gingivalis are closely associated with periodontal status, and that quantitative analysis of this organism is important for the evaluation of periodontal therapy.     

The host cytokine response to Porphyromonas gingivalis is modified by gingipains

Background/aims:  Clinical studies indicate that primary proinflammatory cytokines, such as interleukin-1β (IL-1β) are elevated in the gingival crevice around teeth with periodontitis but the secondary cytokines and chemokines, IL-6 and IL-8, are not. The human gingival epithelial cells (HGECs) lining the gingival sulcus respond to perturbation by microbes of dental plaque by releasing a wide range of cytokines. Porphyromonas gingivalis , a putative periodontal pathogen, possesses numerous virulence factors some of which directly impact on the host response. In the present study, we sought to determine how P. gingivalis influences the inflammatory cytokine responses.
Methods:  HGECs were challenged with P. gingivalis and other putative periodontal pathogens, and the resultant production of IL-1β, IL-6, and IL-8 was assayed by enzyme-linked immunosorbent assay (ELISA). Culture supernatants and recombinant human cytokines were challenged with live P. gingivalis wild-type and gingipain-deficient strains and the resultant cytokine profile was assessed by ELISA and Western blot.
Results:  We show here that primary HGECs challenged with live P. gingivalis result in high levels of IL-1β but not the related secondary cytokines IL-6 and IL-8. We further demonstrate that cytokine response differences are the result of the action of P. gingivalis proteases, with lysine gingipain being the most effective.
Conclusion:  We conclude that P. gingivalis , through lysine gingipain, can subvert the protective host proinflammatory response by direct cytokine degradation. Changes in the crevicular cytokine profile have consequences in periodontal disease pathogenesis that should be considered in the development of diagnostic and therapeutic modalities.     

Serum antibodies against the hemoglobin-binding domain (HA2) of Porphyromonas gingivalis

BACKGROUND: The hemoglobin-binding domain (HA2) of the Porphyromonasgingivalis gingipains and hemagglutinins strongly binds hemoglobin and hemin and is thought to play a key role in acquisition of this essential metabolite by the microorganism. METHODS: In this report, we partially characterized human anti-HA2 humoral antibodies and their relationship to periodontal disease in an analysis of titer and function. RESULTS: Overall, serum anti-HA2 antibodies were relatively low and dominated by the immunoglobulin M (IgM) isotype. Pre-therapy titers had a direct association with periodontal health. Levels of P. gingivalis in the plaque were directly related to pre-therapy anti-HA2 IgG levels, and were an important covariant in a significant direct relationship between pre- and post-therapy anti-HA2 titers. Post-therapy anti-HA2 IgG antibody titers were directly related to the capacity of serum IgG fractions to neutralize hemoglobin binding by Lys-gingipain (Kgp). Further, lower levels of neutralizing activity post-therapy were directly related to severe periodontitis within the patient cohort. CONCLUSIONS: These data suggest that anti-HA2 IgG antibodies correspond directly with periodontal health, possibly through their ability to neutralize P. gingivalis hemoglobin capture. The data also suggest that inadvertent or therapeutic inoculation of P. gingivalis in the plaque may contribute to generation of neutralizing anti-HA2 IgG and improvement of periodontal prognosis.     

成人正畸患者龈下菌斑中牙龈卟啉单胞菌的变化

目的研究成人正畸患者在固定矫治器戴入后,其牙周临床指标和龈下菌斑中牙龈卟啉单胞菌（P.gingivalis）的早期变化。方法选择成人正畸患者11例,分别在矫治器戴入前,戴入后第1、3个月检查牙周临床指标（包括菌斑指数、龈沟出血指数、探诊深度和附着丧失）,同时采集龈下菌斑样本,利用荧光实时定量聚合酶链反应检测样本中P.gingivalis和总细菌的数量,计算出P.gingivalis的检出率和构成比。分析牙周临床指标和P.gingivalis的检出率、构成比在不同观察时点的变化情况。结果菌斑指数、龈沟出血指数在矫治器戴入后均比戴入前明显升高（P<0.05）。探诊深度在矫治器戴入1个月后升高（P<0.05）,3个月后下降至基线水平。试验中未发现有探诊深度大于2 mm的患者,也未发现有附着丧失的患者。在3次检测中,P.gingivalis检出率均为45.5%,而P.gingivalis构成比的变化也无统计学差异（P>0.05）。结论固定矫治器戴入早期可引发成人正畸患者口内局部菌斑堆积,菌群中P.gingivalis增殖,出现轻度牙龈炎。     

不同fimA基因型牙龈卟啉单胞菌对牙龈成纤维细胞基质金属蛋白酶表达的影响

目的 观察不同fimA基因型牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)对人牙龈成纤维细胞基质金属蛋白酶(matrix metalloproteinases,MMP)表达水平的影响,探讨fimA基因型与Pg致病力之间的关系.方法 Pg ATCC 33277(Ⅰ型)、WCSP115(Ⅱ型)、WCSP1.5(Ⅲ型)、W83(Ⅳ型)分别与牙龈成纤维细胞在标准条件下共同孵育(对照组为达尔伯克氏改良伊格尔培养基),于孵育后1、3、6和12 h收集细胞和培养上清液,应用实时荧光定量反转录聚合酶链反应(RT-PCR)和ELISA法分别检测牙龈成纤维细胞MMP-1、MMP-2的mRNA及蛋白的动态表达.结果 与对照组相比,Pg刺激下牙龈成纤维细胞MMP-1、MMP-2的mRNA和蛋白水平表达量均明显上调(P<0.01);其中Ⅱ型fimA型Pg的刺激作用强于其他各型,不同时间点MMP-1 mRNA相对表达量及蛋白分泌水平分别为(28.88±3.12)～(231.01±24.99)、(1.35±0.17)～(3.08±1.20);MMP-2 mRNA相对表达量及蛋白分泌水平分别为(20.42±2.21)～(188.34±37.37)、(2.57±0.76)～(18.08±1.15),与其他各型相比差异有统计学意义(P<0.05);Ⅲ型Pg的刺激作用较弱,不同时间点MMP-1 mRNA相对表达量及蛋白分泌水平分别为[(5.11±0.55)～(72.84±8.84)]μg/L、[(0.68±0.13)～(1.46±0.94)]μg/L;MMP-2 mRNA相对表达量及蛋白分泌水平分别为[(4.55±0.55)～(25.75±3.12)]μg/L、[(2.28±0.93)～(11.22±2.46)]μg/L,与其他各型相比差异有统计学意义(P<0.05).结论 Pg可以诱导牙龈成纤维细胞过表达MMP,fimA基因型与Pg的毒力作用相关,fimA型可能为Pg致病力差异的基因基础.     

Porphyromonas gingivalis induction of mediator and cytokine secretion by human gingival fibroblasts

We hypothesized that bacterial viability and strain characteristics of Porphyromonas gingivalis could affect the induction of pro-inflammatory mediator secretion by human gingival fibroblast cultures. Both killed and viable P. gingivalis elicited production of prostaglandin E2, interleukin-1 beta (IL-1 beta), IL-6 and IL-8, although killed P. gingivalis induced generally higher levels, particularly IL-6 and IL-8, compared with the viable bacteria. P. gingivalis strains, which exhibited wild-type levels of trypsin-like protease activity, stimulated human gingival fibroblasts to secrete increased levels of prostaglandin E2 and IL-1 beta, although minimal levels of IL-6 and IL-8 were noted in supernatants from the gingival fibroblast cells. P. gingivalis strains BEI and NG4B19, which have either decreased or undetectable levels of trypsin-like protease, respectively, induced significantly greater IL-6 and IL-8 levels in gingival fibroblast cultures compared with the other strains. The ability of antibody to P. gingivalis to alter human gingival fibroblast production of pro-inflammatory mediators was tested using nonhuman primate antisera. Both immune and nonimmune sera altered the P. gingivalis-generated pattern of mediators from the gingival fibroblasts. We conclude that: (i) viable and killed P. gingivalis were capable of inducing various pro-inflammatory cytokines from human gingival fibroblasts; (ii) strain differences in cytokine induction were noted, and the expression of a trypsin-like protease activity was related to decreased extracellular levels of IL-6 and IL-8; and (iii) the presence of serum, particularly with specific antibody to P. gingivalis, significantly altered human gingival fibroblast cytokine production compared with P. gingivalis alone.     

Clonal analysis of Porphyromonas gingivalis by the arbitrarily primed polymerase chain reaction

Genetic analysis of Porphyromonas gingivalis strains may distinguish between virulent and nonvirulent strains and also may be used to trace individual strains in epidemiological studies. The present study examined the utility of the arbitrarily primed polymerase chain reaction for genotypic fingerprinting of P. gingivalis. DNA was extracted according to conventional methods. Ten-base oligonucleotide primers with arbitrary sequences were used with the polymerase chain reaction to amplify P. gingivalis genomic DNA. The amplification products were analyzed by agarose gel electrophoresis. The primer GACCGCTTGT grouped 73 P. gingivalis strains into 23 genotypes, including 16 genotypes containing a single strain each. The primer AGGGGTCTTG identified 45 different genotypes, 33 of which contained a single strain. P. gingivalis strains ATCC 332771^T and 381 belonged to the same genotype. Likewise, strains W50 and W83 were of the same genetic clone. The present study indicates that the arbitarily primed polymerase chain reaction represents a valuable and easy method for clonal analysis of P. gingivalis.     

Adhesion and invasion to epithelial cells by fimA genotypes of Porphyromonas gingivalis

Adhesion to and invasion of epithelial cells by the periodontopathogen Porphyromonas gingivalis is promoted by the major fimbriae, encoded by fimA. The microorganism can be classified in six genotypes, based on fimA sequence, and genotype II strains are more prevalent than others in periodontitis patients. This study aimed to determine the adhesive and invasive abilities on KB cells of different fimA allelic variants of P. gingivalis isolates. Twenty-two isolates and six reference strains representing the six fimA genotypes and non-typeable strains were screened for their adhesion and invasion abilities on KB cells, using standard methods. All strains were able to adhere and, except for one, to invade KB cells. However, these properties were not homogeneous among strains belonging to the same genotype. There was no correlation between adhesion and invasion efficiencies. Isolate KdII 865 (fimA genotype II) was the most invasive and the second most adhesive strain, whereas reference strain ATCC 33277 (fimA I) showed a low adhesion ability but was highly invasive. These data indicated that fimA genotypes of P. gingivalis are not related to the adhesion and invasion abilities on KB cells, suggesting that the increased prevalence and proportion of certain genotypes may be attributed to other characteristics besides FimA variation.     

自锁托槽与传统托槽对牙周指数和牙龈卟啉单胞菌影响的对比研究

目的 对比正畸患者粘接自锁托槽与传统托槽后牙周指数和牙龈卟啉单胞菌的变化。方法 将正畸患者30例按托槽类型分为2组,每组15例。试验组粘接Clippy自锁托槽,对照组粘接O-PAK传统直丝弓托槽。分别在矫治器戴入前,戴入后第1、3个月检查牙周临床指标（包括菌斑指数、牙龈指数、探诊深度）,同时采集龈下菌斑样本,利用实时荧光定量聚合酶链反应检测样本中牙龈卟啉单胞菌和总细菌的数量,计算出牙龈卟啉单胞菌的构成比。结果 治疗前试验组与对照组牙周指数、牙龈卟啉单胞菌构成比差异无统计学意义（P＞0.05）。治疗中,2组牙周指数、牙龈卟啉单胞菌构成比均随时间延长而升高（P＜0.05）;试验组在粘接矫治器后第1、3个月,牙周指数、牙龈卟啉单胞菌构成比均低于对照组（P＜0.05）。结论 与传统托槽对比,自锁托槽更利于口腔卫生维护,但仍会对口腔卫生造成不利影响。     

成人牙周健康状况与fimA基因型牙龈卟啉单胞菌的相关性

目的分析不同fimA基因型牙龈卟啉单胞菌（P.gingivalis）在牙周健康人群和慢性牙周炎人群中的分布,探讨不同fimA基因型P.gingivalis与成人牙周状况的相关关系。方法收集牙周健康组（136例）和慢性牙周炎组（115例）的龈下菌斑样本,采用16S rRNA PCR法检测P.gingivalis,并根据各fimA基因型（Ⅰ～Ⅴ和Ⅰb）的特异性引物检测不同fimA基因型P.gingivalis菌株的分布,计算OR值和95%可信区间。结果牙周健康组和慢性牙周炎组龈下菌斑样本中P.gingivalis阳性率分别为22.1%和81.7%,多数样本中只检测到1种fimA基因型。牙周健康组中ⅠfimA型的检出率最高（占66.7%）;慢性牙周炎组中则为ⅡfimA基因型（占43.6%）,其次为Ⅳ和Ⅰb fimA基因型。慢性牙周炎的发生与P.gingivalis的关系密切（OR=16.36）,Ⅰ、Ⅰb、Ⅱ、Ⅲ、Ⅳ、ⅤfimA基因型P.gingivalis与慢性牙周炎相关性的OR值分别为0.97、13.26、36.62、4.57、22.86、1.19;ⅡfimA基因型P.gingivalis与慢性牙周炎的相关性最强,其次为Ⅳ和Ⅰb型。结论P.gingivalis菌株的fimA基因型存在差异,特异性fimA基因型P.gingivalis可能与成人慢性牙周炎的发生关系密切。     

Polymerase chain reaction for the identification of Porphyromonas gingivalis collagenase genes

Porphyromonas gingivalis has been shown to exhibit genetic diversity possibly resulting in variation of virulence. In the present study a potential virulence factor was targeted for the detection of P. gingivalis. A 548 bp fragment of the collagenase gene ( prtC ) from Porphyromonas gingivalis ATCC 33277 was amplified by polymerase chain reaction (PCR) using oligonucleotides derived from the middle portion of prtC. From 16 of 21 clinical P. gingivalis strains, a PCR product of similar size to the prtC could be obtained. These 16 P. gingivalis strains were confirmed as positive for prtC using DNA hybridization with a digoxigenin-labeled prtC PCR product as a probe. In 12 of the 16 prtC positive strains, the restriction analysis of the PCR products revealed fragment patterns identical to the known sequence. In the other 4 prtC positive strains, 4 distinct patterns were found. Of these strains, nucleotide sequence analysis of a 400 bp PCR product stretch revealed 79.1%, 83.0%, 84.8 and 89.5% homology with the known nucleotide sequence for this specific region. Sequence analysis of the PCR products from the ATCC 33277 strain demonstrated 93.7% homology. The limit of detection for the PCR was about 100 organisms. None of the other 48 tested strains of 16 bacterial species derived from oral and extraoral infections yielded a PCR product. The PCR was also used for the detection of prtC sequences in dental plaque. Our data indicate that not all P. gingivalis strains have prtC. Nucleotide heterogeneity exists among P. gingivalis with prtC. Using a potential virulence factor for the detection of putative periodontal pathogens such as P. gingivalis may be valuable for the epidemiology of infection and clinical diagnosis of periodontal diseases.     

不同fimA基因型牙龈卟啉单胞菌在青春期龈炎患者中的分布

目的:分析不同fimA基因型牙龈卟啉单胞菌(Porphyromonas gingivalis,P.gingivalis)在青春期龈炎患者和青春期牙周健康者中的分布。方法:收集51例青春期龈炎患者和46例青春期牙周健康者的龈下菌斑,采用16SrRNA PCR检测P.gingivalis,并根据各fimA基因型的特异引物,用PCR检测不同fimA基因型菌株的分布。结果:龈炎组各fimA基因型P.gingivalis的总检出率:Ⅰ型34.2%,Ⅱ型55.3%,Ⅳ型18.4%,Ⅲ型和Ⅴ型未检出;另有7例(占18.4%)未分出型别。健康组各fimA基因型P.gingivalis的总检出率:Ⅰ型14.3%,Ⅱ型85.7%,Ⅲ型14.3%,Ⅳ型28.6%,Ⅴ型未检出;另有2例(占14.3%)未分出型别。结论:青春期龈炎和青春期牙周健康者龈下菌斑中的P.gingivalis存在fimA基因多态性。fimA基因Ⅱ型是其主要存在的基因型,其次是Ⅰ型和Ⅳ型,Ⅲ型和Ⅴ型较少或不能检出。     

Prevalence of Porphyromonas gingivalis fimA genotypes in Caucasians

The aim of the present study was to determine the prevalence of Porphyromonas gingivalis fimA genotypes in Caucasian patients with periodontitis. A total of 102 patients harboring P. gingivalis subgingivally were enrolled into the study. Pooled subgingival plaque samples of the six most severely affected sites were taken and analysed by fimA-specific polymerase chain reaction (PCR) and restriction analysis. Moreover, 26 P. gingivalis isolates were analysed by sequence analysis of the fimA gene. Sequence analysis revealed five major fimA genotypes (fimA types I-V) and allowed further subtyping of fimA genotypes II and IV into two subgroups each. The overall prevalences of fimA genotypes as assessed by PCR and restriction analysis among the P. gingivalis-positive patients with periodontitis were: type I, 25.5%; type II, 38.2%; type III, 4.9%; type IV, 18.6%; type V, 3.9%; and non-typable, 6.9%. Two patients were colonized by both type II and type IV, or type III and type IV fimA genotypes, respectively. Patients harboring different fimA genotypes showed no significant difference in severity of periodontal disease, as assessed by pocket probing depth and bleeding on probing following adjustment for smoking habit and age. The results indicate that predominant fimA genotypes in Caucasian periodontitis patients are types I, II, and IV. However, there was no difference in the association of the various fimA genotypes with disease severity.     

慢性牙周炎患者龈下菌斑中不同基因型牙龈卟啉单胞菌的检测

摘要 目的:建立临床标本中牙龈卟啉单胞菌(P.g)的PCR检测方法,探讨慢性牙周炎患者不同牙位的龈下菌斑中P.g基因型的差异。方法:采用培养法分离鉴定慢性牙周炎患者不同牙位龈下菌斑中P.g,同时采用PCR检测 P.g16SrDNA、prtC和fimA基因。部分扩增产物测定了核苷酸序列。结果:在66例患者的127个龈下菌斑标本中, P.g16SrDNA、prtC和fimA多重引物扩增的阳性率为9814%;PCR阳性率显著高于培养法P.g的检出率(P< 0101)。3010%的患者(18/60)同时感染了不同基因型的P.g菌株。P.g16SrDNA、prtC和fimA扩增片段的核苷酸序列同源性在98162%~100%之间。结论:本文所建立的P.g的PCR检测方法具有较高的敏感性和特异性,适用于P.g的快速临床诊断。同一患者可被不同感染来源的多株P.g同时感染。     

Variations of Porphyromonas gingivalis fimbriae in relation to microbial pathogenesis

OBJECTIVES: Periodontal disease is an infectious disorder caused by a small subset of periodontal pathogens including Porphyromonas gingivalis. Accumulated evidences show that the expression of P. gingivalis heterogenic virulence properties is dependent on its clonal diversity. P. gingivalis expresses two distinct fimbria molecules, major and minor fimbriae, on its cell surfaces, both of which seem to be involved in the development of periodontitis. In this short review, variations of fimbriae in relation to microbial pathogenesis are discussed. MATERIALS AND METHODS: Our recent findings are summarized to elucidate the relationship between clonal variation of fimbriae and bacterial pathogenicity of various strains. RESULTS: Major fimbriae were classified into six types (I to V and Ib) based on the diversity of fimA genes encoding FimA (a subunit of major fimbriae). A majority of periodontitis patients were found to carry type II fimA organisms, followed by type IV, and type II fimA organisms were significantly occurred with more severe forms of periodontitis. Studies of clones with type II fimA have revealed significantly greater adhesive and invasive capabilities to epithelial cells than other fimA type clones. Minor fimbriae induced interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha) cytokine expression in macrophages and were suggested to be a causative factor of alveolar bone resorption in animal models. The clonal diversity of minor fimbriae is unclear, however, distinct minor fimbria molecules were found in different strains. CONCLUSION: The fimbria variations may have an influence on the development of periodontal disease.     

两种fimA基因型牙龈卟啉单胞菌刺激下口腔上皮细胞ICAM-1的表达

目的比较2种fimA基因型牙龈卟啉单胞菌（Porphyromonas gingivalis,P．gingivalis）刺激下口腔上皮细胞ICAM-1的表达水平。方法实验组用P．gingivalis ATCC 33277（Ⅰ型菌毛组）,W83（Ⅳ型菌毛组）,47A-1（Ⅳ型菌毛组）分别与KB细胞（ATCC CCL17）共同孵育24h;对照组为未受P.gingivalis刺激的KB细胞。分别在1h、3h、6h和24h收集细胞,运用流式细胞仪检测KB细胞膜上ICAM-1的动态表达。结果P．gingivalis刺激细胞后3h、6h和24h,实验组ICAM-1的表达水平均高于对照组;2种fimA基因型P．gingivalis调节KB细胞表达ICAM-1的方式相似,Ⅳ型菌毛组的调节作用强于Ⅰ型菌毛组。结论P.gingivalis上调口腔上皮细胞表达ICAM-1的水平与其fimA基因型相关,提示P.gingivalis致病性与其fimA基因型相关。     

维吾尔族慢性牙周炎中牙龈卟啉单胞菌菌fimA毒力基因型的分布

目的：分析维吾尔族慢性牙周炎患者龈下菌斑中牙龈卟啉单胞菌菌毛fimA毒力基因型的分布情况。方法：收集52例维吾尔族慢性牙周炎患者的龈下菌斑，采用16SrRNA PCR法检测牙龈卟啉单胞菌，并根据菌毛fima毒力基因型的特异引物，用聚合酶链反应（PCR）检测Ⅱ型fimA和Ⅳ型fima菌株的分布。结果：16SrRNA PCR法检测牙龈卟啉单胞菌在龈下菌斑中阳性检出率是76．9％。牙周袋PPD〉6mm位点龈下菌斑标本的P．gingivalis检出率高于4〈PPD≤6mm采样的位点，2组差异有统计学意义（P〈0．05）。牙龈卟啉单胞菌菌毛．fimA毒力基因型在牙龈卟啉单胞菌感染者的检出率分别是：Ⅱ fimA型为37．5％，ⅣfimA型为22．5％。结论：维吾尔族慢性牙周炎患者龈下菌斑中牙龈卟啉单胞菌有较高的检出率。牙龈卟啉单胞菌存在fima毒力基因多态性。