Clonal diversity of the taxon Porphyromonas gingivalis assessed by random amplified polymorphic DNA fingerprinting

Abstract

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.

Phylogenetic analysis of Porphyromonas species isolated from the oral cavity of Australian marsupials

“…The evolutionary distance tree generated confirmed that strains within each Group 2 subclade are highly related, despite being isolated from different geographical locations and animal species. The identification of these three distinct subclades supports earlier genotypic studies confirming the existence of considerable genetic heterogeneity among strains now recognized as P. gulae (Loos et al, 1993;Chen and Slots, 1995;Menard and Mouton, 1995;Fournier et al, 2001). Sequence analysis confirmed that the three eastern grey kangaroo strains and two strains from a pretty-faced wallaby were phylogenetically closely related to cat, dog and bear P. gulae sequences even though the isolates came from two geographically distinct locations: Sydney, Australia and Québec, Canada.…”

Detection and Clonal Analysis of Anaerobic Bacteria Associated to Endodontic‐Periodontal Lesions

“…Similar behavior seems not to occur with species of the genus Porphyromonas, which are considered more fastidious and therefore, may be underestimated by culture methods such as those applied in the present study. 1,25 Tables 3 and 4 indicate that there was the simultaneous colonization in the pulp and periodontal anatomic sites by all species tested. Pg was the most prevalent, followed by Pe, which is the same prevalence order reported in the literature, 4 with values of 72% and 56%, respectively.…”

Systemic antibiotic therapy in periodontics

“…Both bacteria exhibit a low prevalence in periodontal health and gingivitis (91, and the immune response towards these bacteria markedly exceeds that characteristic of endogenous infections (198). DNA fingerprinting techniques (36,104,105,162,217,218) have provided evidence for these species being transmitted from parent to child and between spouses (36, 37,45,122,160,161,164,219). Table 13 summarizes studies on transmission of A. actinomycetemcomitans and l?…”