Phylogenetic diversity in fim and mfa gene clusters between Porphyromonas gingivalis and Porphyromonas gulae, as a potential cause of host specificity

Abstract

Background: Periodontopathic bacteria Porphyromonas gingivalis in humans and Porphyromonas gulae in animals are phylogenetically close and commonly have FimA and Mfa1 fimbriae. However, little is known about how fimA and mfa1 are phylogenetically different between P. gingivalis and P. gulae. Here, we examined phylogenetic diversity in their fim and mfa gene clusters. Methods: Twenty P. gulae strains were isolated from the periodontal pocket of 20 dogs. For their genomic information, along with 64 P. gingivalis and 11 P. gulae genomes, phylogenetic relationship between the genotypes of fimA and mfa1 was examined. Variability of amino acid sequences was examined in the three-dimensional structure of FimA. The distance between strains was calculated for fim and mfa genes. Results: Some fimA genotypes in P. gulae were close to particular types in P. gingivalis. Two types of mfa1 were classified as 70-kDa and 53-kDa protein-coding mfa1. The variable amino acid positions were primarily at the outer part of FimA. The genes encoding the structural proteins and the main component were similarly distant from the reference strain in P. gingivalis, but not in P. gulae. Conclusions: The differences in the gene clusters between P. gingivalis and P. gulae may result in their host specificity.

Diversity analysis of genes encoding Mfa1 fimbrial components in Porphyromonas gingivalis strains

“…The fimA gene has been classified into six genotypes (I to V, and Ib) based on either PCR using genotype-specific primers, or on the presence or absence of restriction enzyme cleavage [8]. However, genotype Ib is now unified into genotype I because of their similar antigenicity and overall DNA sequences [13,14]. Studies from many countries have reported that genotypes II and IV are predominantly detected in patients with severe periodontitis, whereas genotype I is prevalent in healthy or mild periodontitis subjects [8,15,16].…”

Exploring the genetic and functional diversity of Porphyromonas gingivalis long fimbriae

“…The NJ‐cladograms and NJ‐phylograms of 50 fimA genotypes and 133 FimA serotypes all showed the same eight distinct clusters A–H along with some outliners (possibly hybrid strains) corresponding to type A of P. gulae and seven human fimA /FimA P. gingivalis subtypes, including two II‐subtypes (a and b) for nomination. Cluster A, containing all six P. gulae animal isolates with fimA type A (Fujiwara‐Takahashi et al., 2020). We hereby propose that it possibly represents the ancestral sequence of the fimA gene as frequently found and especially in monkeys.…”

Prevalence of Periodontal Pathogens in Slovak Patients with Periodontitis and Their Possible Aspect of Transmission from Companion Animals to Humans

“…In dogs, periodontal disease is mainly associated with the presence of P. gulae , which was originally thought to be the animal biotype of P. gingivalis ; however, it was also found to colonize human oral cavity [ 69 ]. P. gulae has similar characteristics as P. gingivalis [ 70 ], which may result in the potential transmission between animals and their owners [ 23 ]. It possesses a broad spectrum of pathogenic properties such as lipopolysaccharide, haemagglutinins, fimbriae and proteases [ 71 ].…”

“…Besides that, Nomura et al [ 73 ] found that certain FimA types of fimbrial protein of canine P. gulae were phylogenetically close to those of P. gingivalis . Moreover, Fujiwara-Takahashi et al [ 70 ] found that FimA types I, III, and IV in P. gingivalis were close to types A, B, and C, respectively, in P. gulae in dogs. Iwashita et al [ 74 ] identified the fimA genotypes in feline P. gulae isolates, as well.…”