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.     

Distribution of Porphyromonas gingivalis fimA genotypes in patients affected by rheumatoid arthritis and periodontitis

Objective: To determine and compare the distribution of Porphyromonas gingivalis fimA genotypes in patients affected by Rheumatoid arthritis (RA) and periodontitis (PE).

Materials and methods: This study involved 394 subjects divided into four groups, RA, PE, RA and PE and healthy subjects. PE was diagnosed by using clinical attachment loss (CAL) and probing depth (PD) indexes. Presence of P. gingivalis and its genotypes was identified by polymerase chain reaction in subgingival biofilm.

Results: P. gingivalis was more frequent in patients with RA (82.69%), and fimA II genotype was the most frequent in all groups, especially in PE/RA (76.71%). There was statistical difference (p?P. gingivalis genotypes such as fimA Ib, II and III.

Conclusions: Distribution of P. gingivalis fimA II genotypes was different among groups, it could play a critical role in the presence of PE in RA patients.     

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.     

fimA genotypes and PFGE profile patterns in Porphyromonas gingivalis isolates from subjects with periodontitis

Background and objectives:  Porphyromonas gingivalis is frequently identified to type by evaluation of fimA polymorphisms and less often by pulsed-field gel electrophoresis (PFGE) because of the technical intricacies of PFGE. To compare these techniques, we genotyped P. gingivalis clinical isolates as to (i) their fimA type and (ii) their whole genome restriction profile (PFGE analysis).
Material and methods:  Thirty-two P. gingivalis strains were isolated from 16 unrelated periodontitis patients. Two strains were isolated from each patient. Strains were subjected to a fimA -typing polymerase chain reaction (PCR) assay. Strains that could not be typed by PCR were submitted to sequencing of the entire fimA gene. The PFGE profiles of clinical strains were compared using bioinformatic analysis.
Results:  Seven of the 32 isolates were not typeable by PCR and so their entire fimA gene was sequenced. The sequencing identified each strain as belonging to a single fimA type. In one case, sequencing of the fimA gene did not agree with the result obtained using fimA PCR typing. With the exception of one patient, each patient presented isolates bearing the same fimA type. However, in three patients, isolates with the same fimA type presented different PFGE pulsotypes.
Conclusion:  The P. gingivalis typing using fimA PCR has limitations in typeability and discriminatory power. A typing technique for P. gingivalis that is easy to perform but that presents adequate typeability and discriminatory power is needed if we want to better understand the epidemiology of periodontal disease.     

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。     

不同fimA型牙龈卟啉单胞菌降解上皮细胞间连接蛋白能力的初步研究

目的:研究不同fimA型牙龈卟啉单胞菌(Porphyromonas gingivalis,P.g)破坏上皮细胞间连接能力,探讨fimA基因型与致病力差异之间的关系。方法:应用不同fimA型P.g菌株ATCC 33277(Ⅰ型),WCSP115(Ⅱ型),WCSP1.5(Ⅲ型),W83(Ⅳ型),3501(Ⅴ型),4702(Ib型)分别与口腔上皮细胞系KB细胞在标准条件下共同孵育,于孵育后0.5、1和3 h,收集细胞蛋白,应用Westen-blot检测N-钙粘素(N-cadherin)和β-连环素(β-Catenin)的动态表达。结果:与对照组比较,各fimA型P.g对KB细胞N-cadherin和β-Catenin蛋白的表达均有明显的降解作用;其中ⅡfimA型组N-cadherin和β-Catenin蛋白的表达量低于其它fimA型组。结论:P.g可破坏上皮细胞间连接成分,破坏上皮细胞的完整性,而Ⅱ型fimA型P.g水解上皮细胞间粘合连接蛋白的能力强于其它fimA型。提示fimA基因型的不同可能是P.g的致病力差异的基因基础。     

感染根管中牙龈卟啉单胞菌fimA基因多态性研究

目的研究根尖周炎患牙感染根管内牙龈卟啉单胞菌(P.gingivalis)不同fimA基因型的分布情况。方法收集200例感染根管内样本,经DNA抽提后使用16S r DNA PCR方法检测P.gingivalis。在P.gingivalis检出阳性样本中,根据各fimA基因型的特异引物,采用PCR检测不同fimA基因型菌株的分布,并通过Pearsonχ2检验对不同fimA基因型与临床症状进行相关性分析。结果感染根管中P.gingivalis的检出率为48%,其中79例样本只检测到1种fimA基因型P.gingivalis菌株(82.3%);12例样本检测到2种或2种以上fimA基因型P.gingivalis(12.5%)。各fimA基因型P.gingivalis的检出情况:Ⅰ型29.2%、Ⅰb型8.3%、Ⅱ型37.5%、Ⅲ型14.6%、Ⅳ型19.8%。各型fimA基因与临床症状之间无统计学相关性(P<0.05)。结论感染根管内P.gingivalis的fimA基因存在基因多态性,其中以fimAⅡ型P.gingivalis菌株检出率最高,其次为Ⅰ型和Ⅳ型。     

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.     

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.     

维吾尔族慢性牙周炎中牙龈卟啉单胞菌菌毛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16S rRNA 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:16S rRNA 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＞6 mm位点龈下菌斑标本的P.gingivalis检出率高于4＜PPD≤6 mm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:ⅡfimA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.     

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。     

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。     

不同fimA基因型牙龈卟啉单胞菌刺激口腔上皮细胞白细胞介素-8的表达

目的比较不同fimA基因型牙龈卟啉单胞菌（P.gingivalis）刺激下口腔上皮细胞白细胞介素-8（IL-8）的表达水平,初步探讨P.gingivalis致病性与其fimA基因型的关系。方法P.gingivalis ATCC 33277（Ⅰ型fimA）、W83、47A-1（Ⅳ型fimA）和KB细胞ATCC CCL-17共同孵育24 h,以未受刺激的KB细胞作为对照组,分别在1、3、6、24 h收集细胞和培养上清液。RT-PCR检测KB细胞IL-8 mRNA的动态表达,酶联免疫反应检测培养上清液中IL-8的动态变化。结果2种fimA基因型菌株刺激1 h,KB细胞IL-8 mRNA的表达上调至峰值,高于对照组,3~24 h IL-8 mRNA的表达水平接近对照组;P.gingivalis感染细胞后3~24 h,上清液中的IL-8水平低于对照组,Ⅳ型菌株低于Ⅰ型菌株;IL-8 mRNA及其蛋白表达不完全一致,提示IL-8的表达存在转录后水平的调节。结论fimA基因型与口腔上皮细胞IL-8的表达水平相关,提示P.gingivalis致病性与其fimA基因型相关。     

Comparison of inflammatory changes caused by Porphyromonas gingivalis with distinct fimA genotypes in a mouse abscess model

The fimA gene of Porphyromonas gingivalis, encoding fimbrillin (a subunit protein of fimbriae) has been classified into six genotypes (types I-V and Ib). The genotypic variation was previously suggested to be related to the severity of adult periodontitis in the general population. In this study, we compared inflammatory changes caused by bacterial infection to study pathogenic heterogeneity among the different fimA strains in a mouse abscess model. Bacterial suspensions of 13 P. gingivalis strains representing the six fimA types were subcutaneously injected into female BALB/c mice, and serum sialic acid concentrations were assayed as a quantitative host inflammatory parameter. Type II fimA organisms caused the most significant induction of serum sialic acid, as well as other infectious symptoms, followed by types Ib, IV and V. In contrast, types I and III caused weak inflammatory changes. In addition, fimA mutants of type II strains clearly lost their infectious ability. These findings suggest that fimA genotypic variation affects expression of P. gingivalis virulence.     

牙龈卟啉单胞菌菌毛fimA基因在大肠杆菌的融合表达

目的：克隆牙龈卟啉单胞菌菌毛蛋白fimA基因,并使其在大肠杆菌中融合表达。方法：利用PCR方法克隆fimA,并用基因重组融合表达技术获得在大肠杆菌中的表达。结果：克隆基因测序结果与GenBank数据库中的序列呈现99．9％同源性;经诱导表达后可观察到Mr38kDa的融合蛋白。结论：成功克隆了fimA基因,并在大肠杆菌中表达了FimA蛋白,为后续研究奠定了基础。     

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。     

不同rag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rag基因型牙龈卟啉单胞菌在慢性牙周炎患者中的分布状况。方法收集50例慢性牙周炎患者的150个龈下菌斑样本,采用16S rDNA 聚合酶链反应（PCR）法检测牙龈卟啉单胞菌在牙周炎病变位点的检出率,并根据各rag基因型的特异性引物检测牙龈卟啉单胞菌不同rag基因型在慢性牙周炎病变位点的分布。结果经16S rDNA PCR法检测,病变位点牙龈卟啉单胞菌阳性检出率为70.7%。各rag基因型在牙龈卟啉单胞菌阳性位点的总检出率：rag-1为60.4%,rag-2为23.6%,rag-3为44.3%,rag-4为15.1%;经统计学检验,rag-1和rag-3型检出率较高,高于rag-2和rag-4型（P<0.05）。结论慢性牙周炎患者龈下菌斑中的牙龈卟啉单胞菌存在rag基因多态性,rag-1和rag-3基因型牙龈卟啉单胞菌与中国辽宁地区人群慢性牙周炎的发生发展关系密切。     

Relationship of periodontal bacteria and Porphyromonas gingivalis fimA variations with phenytoin-induced gingival overgrowth

OBJECTIVES: We investigated the relationship between phenytoin-induced gingival overgrowth (GO) and the harboring of periodontal bacteria. MATERIALS AND METHODS: Periodontal conditions and subgingival bacterial profiles were examined in 450 sites of 75 subjects. A polymerase chain reaction method was used to detect six bacterial species; Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Tannerella forsythia, Treponema denticola (Td), Prevotella intermedia (Pi), and Prevotella nigrescens (Pn). Genetic variations of the Pg fimA gene were also examined. Bacterial occurrence was compared with the severity of GO, and alterations in the bacterial occurrence rate and quantities were monitored following periodontal treatment. RESULTS: The occurrences of Aa, Td, Pi, Pn, and Pg with type II fimA (type II Pg) were significantly associated with the severity of GO. Td occurrence was reduced in association with gingival improvement following ultrasonic scaling, however, no such relationship was observed with Aa, Pi, Pn, and Pg. In addition, Pg and Pi markedly persisted after treatment. Clinical improvement of the sites, following an Er:YAG laser treatment, significantly associated with quantitative reduction of Pg in improved sites, however, not that of Pi. CONCLUSION: Type II Pg and Td were each found to have a significant relationship with the development and deterioration of GO.     

Distribution of fimA genotypes of Porphyromonas gingivalis in subjects with various periodontal conditions

Fimbria encoded by the gene fimA is considered one of the main factors in the colonization of the oral cavity by Porphyromonas gingivalis. Allelic variation in fimA led to the classification of strains of P. gingivalis into six genotypes. The occurrence of P. gingivalis was determined by polymerase chain reaction using 16S rRNA primers in 302 subgingival samples obtained from 102 Brazilian subjects exhibiting different periodontal conditions. Distribution of fimA genotypes was assessed in 146 P. gingivalis positive samples by polymerase chain reaction using primers pairs homologous to the different fimA genes. P. gingivalis was detected in 51 of 57 (89.4%) patients with periodontal attachment loss, in six of 20 gingivitis patients (30.0%) and in two of 25 (8.0%) subjects with a healthy periodontium. Variant type II was the only type detected in 53 sites (39.3%), distributed among 19 periodontitis patients (37.3%) and in one patient with no periodontal destruction. Type Ib was the second most prevalent genotype in periodontitis patients (19.6%). Genotype V was not detected in the studied population. Type IV was the most commonly type found among gingivitis patients, either alone or in combination with other genotypes. Multiple genotypes were detected in nine sites (6.1%). A fimA genotype was not identified in 26 sites (17.8%) of 146 sites positive for P. gingivalis, suggesting that other alleles of fimA not yet sequenced may be prevalent in this population. These data demonstrated that P. gingivalis type II strains followed by type Ib are more prevalent in periodontitis patients from a multiracial population in Brazil, suggesting an increased pathogenic potential of these types.     

Prevalence of fimA genotypes of Porphyromonas gingivalis and periodontal health status in Chinese adults

Background and Objective:  Porphyromonas gingivalis fimbriae play a key role in colonization of the oral cavity. The fimA gene, which encodes fimbrillin ( FimA ), can be classified into six types (I–V and Ib) according to nucleotide sequence. In the present study, we investigated the relationship between the prevalence of P. gingivalis -specific fimA genotypes and periodontal health status in Chinese adults.
Material and Methods:  One-hundred and fifteen patients with chronic periodontitis and 136 periodontally healthy adults were selected. P. gingivalis detection, determination of fimA genotypes, and the co-existence of Actinobacillus actinomycetemcomitans and Tannerella forsythia with various fimA types, were assessed by the polymerase chain reaction. Odds ratios and 95% confidence intervals were calculated for associating the fimA -specific genes with periodontitis.
Results:  P. gingivalis was detected in 22.1% of healthy subjects and in 81.7% of the patients. A single fimA genotype was detected in most samples. In healthy adults, the most prevalent fimA genotype was type I (66.7%). However, type II was detected most frequently (43.6%) in the patient group, followed by type IV (30.9%). The frequency of co-existing A. actinomycetemcomitans and T. forsythia was highest in type II fimA -positive sites. Statistical analysis revealed that periodontitis was associated with occurrences of type I (odds ratio 0.97), Ib (odds ratio 13.26), II (odds ratio 36.62), III (odds ratio 4.57), IV (odds ratio 22.86) and V (odds ratio 1.19).
Conclusion:  P. gingivalis type II followed by type IV were considered as disease-associated strains that account for the pathogenesis of chronic periodontitis in Chinese adults.