Ménard C, Mouton C
Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, Canada.
Infect Immun. 1995 Jul;63(7):2522-31. doi: 10.1128/iai.63.7.2522-2531.1995.
A total of 97 strains of the periopathogen Porphyromonas gingivalis were collected. This collection included laboratory strains and clinical isolates of human origin with diverse clinical and geographical origins. Biological diversity was further increased by including 32 strains isolated from the oral cavities of nine different animal species. Genomic fingerprints of the 129 strains were generated as random amplified polymorphic DNAs (RAPDs) by the technique of PCR amplification with a single primer of arbitrary sequence. Four nonameric oligonucleotides were used as single primers, and the banding patterns of the DNA products separated on agarose gels were compared after ethidium ethidium bromide staining. Distance coeffients based on the positions of the major DNA fragments were calculated, and dendrograms were generated. We identified 102 clonal types (CTs) that could be assembled into three main groups by cluster analysis by the unweighted pair group method with mathematic averages. Group I (n = 79 CTs) included all 97 human strains and 6 monkey isolates. The strains in group II (n = 22 CTs) and III (n = 1 CT) were strongly differentiated from those in group I and included only strains of animal origin; they likely represent two cryptic species within the present P. gingivalis taxon. We observed that strains from Old World monkeys clustered together with the human genotype, whereas strains from New World monkeys clustered with the animal genotype. Our results with human strains also indicated that (i) the population structure is basically clonal, (ii) no dominant or widespread CT could be observed, and (iii) no relationship could be established between specific clusters of CTs and the periodontal status of the host. Our results corroborate previous findings by B. G. Loos, D. W. Dyer, T. S. Whittam, and R. K. Selander (Infect. Immun. 61:204-212, 1993) and suggest that P. gingivalis should be considered a commensal of the oral cavity acting as an opportunistic pathogen. Our results are not consistent with the hypothesis that only a few virulent clones of P. gingivalis are associated with disease.
共收集了97株牙周病原菌牙龈卟啉单胞菌。该菌株库包括实验室菌株以及来自人类的临床分离株，它们具有不同的临床和地理来源。通过纳入从9种不同动物口腔中分离出的32株菌株，进一步增加了生物多样性。通过使用任意序列的单引物进行PCR扩增技术，以随机扩增多态性DNA（RAPD）的形式生成了这129株菌株的基因组指纹图谱。使用4种九聚体寡核苷酸作为单引物，在溴化乙锭染色后，比较在琼脂糖凝胶上分离的DNA产物的条带模式。根据主要DNA片段的位置计算距离系数，并生成树状图。通过非加权组平均法进行聚类分析，我们鉴定出102个克隆型（CTs），这些克隆型可分为三个主要组。第一组（n = 79个CTs）包括所有97株人类菌株和6株猴子分离株。第二组（n = 22个CTs）和第三组（n = 1个CT）中的菌株与第一组中的菌株有明显差异，仅包括动物来源的菌株；它们可能代表了当前牙龈卟啉单胞菌分类群中的两个隐性物种。我们观察到，旧世界猴子的菌株与人类基因型聚集在一起，而新世界猴子的菌株与动物基因型聚集在一起。我们对人类菌株的研究结果还表明：（i）群体结构基本为克隆性；（ii）未观察到占主导或广泛存在的CT；（iii）在特定的CT簇与宿主的牙周状况之间未建立关联。我们的结果证实了B.G. Loos、D.W. Dyer、T.S. Whittam和R.K. Selander之前的研究发现（《感染与免疫》61:204 - 212，1993），并表明牙龈卟啉单胞菌应被视为口腔中的共生菌，作为机会性病原体发挥作用。我们的结果与仅少数牙龈卟啉单胞菌的强毒克隆与疾病相关的假设不一致。
