Investigation of periodontal disease development and Porphyromonas gulae FimA genotype distribution in small dogs.

In dogs, Porphyromonas gulae is a major periodontal pathogen with 41-kDa proteins polymerizing to form a filamentous structure called fimbriae or pili, termed FimA. FimA is classified into three genotypes: A, B, and C, and there are combinations of types A, B, C, A/B, A/C, B/C, and A/B/C. Periodontal disease is the most common oral disease in small dogs, but the periodontal disease status and P. gulae colonization at each dog age and breed remain unclear. In this study, we stratified 665 small dogs and analyzed the periodontal status and distribution of P. gulae with each FimA genotype. Dogs with periodontal disease and FimA genotype tended to increase with age. The dogs with at least one FimA genotype had significantly more severe periodontal disease compared with P. gulae-negative dogs (P < 0.01). Additionally, periodontal status was significantly associated with specific FimA genotype distribution in Toy Poodles and Chihuahuas (P < 0.05), whereas there was no such association in Dachshunds. These results suggest that the onset of periodontal disease and P. gulae colonization are related and progress with age. The relationship between periodontal disease and FimA genotype may differ depending on the dog breeds.

The Effect of Subacute Oral Folic Acid Treatment on Growth of Porphyromonas gulae in Dogs.

Periodontitis is one of the most prevalent infectious diseases in humans and animals. It is a multifactorial disease resulting in attachment loss and tooth loss. Therefore, preventive dentistry, such as daily teeth cleaning or providing dental chews from puppyhood is essential. This study aimed to find an alternative option for preventive dentistry by examining both in vitro and clinically, the antibacterial, antihalitosis, and anti-inflammatory effects of folic acid (FA) in dogs with periodontal disease. The antibacterial and antihalitosis responses of FA were evaluated in vitro using Porphyromonas gulae, a bacterium that plays a significant role in the development of periodontal disease in dogs. Anti-inflammatory responses, such as secretion of IL-1ß, IL-6, and IL-8 induced by P. gulae infection in human gingival epithelium have been studied. This study used dogs with P. gulae-associated periodontal diseases and was conducted by providing a dental chew containing 0.13% FA for 28 days. The viability and halitosis production (hydrogen sulfide and methyl mercaptan) of P. gulae was significantly inhibited by FA in a dose and time-dependent manner. IL-1ß, IL-6, and IL-8 secretion were also significantly suppressed by FA treatment in a dose-dependent manner. In vitro bactericidal, antihalitosis, and anti-inflammatory effects of FA were confirmed in dogs with P. gulae-associated periodontal disease. One month of oral treatment with 0.13% FA-containing dental chews significantly reduced halitosis as well as P. gulae activity. This study suggests that oral treatment with FA can be a preventive option for periodontal disease in dogs as well as humans.

Possible association of fimA genotype of Porphyromonas gulae with the severity of periodontal disease and the number of permanent teeth in dogs.

Previous research has demonstrated that Porphyromonas gulae (P. gulae) significantly contributes to the development of periodontal disease in dogs. Porphyromonas gulae is divided into three subtypes according to the 41-kDa filamentous appendage (fimA), defined as types A, B, and C. This study aimed to elucidate the association between fimA type of P. gulae with the number of permanent teeth, reflecting the severity of periodontal disease. Two hundred twenty-five dogs were categorized by P. gulae fimA type as negative, type A dominant, type B dominant, and type C dominant. The stage of periodontal disease in P. gulae-positive dogs increased with age, particularly in type C dominant dogs. Correspondingly, the number of permanent teeth in P. gulae fimA type C-dominant dogs was significantly lower than that of P. gulae-negative dogs, suggesting there is a significant association between fimA type of P. gulae and the number of permanent teeth resulting from the development of periodontal disease.

Author Correction: Inhibition of Porphyromonas gulae and periodontal disease in dogs by a combination of clindamycin and interferon alpha.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Inhibition of Porphyromonas gulae and periodontal disease in dogs by a combination of clindamycin and interferon alpha.

Porphyromonas gulae is a major periodontal pathogen in dogs, which can be transmitted to their owners. A major virulence factor of P. gulae consists of a 41-kDa filamentous appendage (FimA) on the cell surface, which is classified into three genotypes: A, B, and C. Thus far, inhibition of periodontal disease in dogs remains difficult. The present study assessed the inhibitory effects of a combination of clindamycin and interferon alpha (IFN-α) formulation against P. gulae and periodontal disease. Growth of P. gulae was significantly inhibited by clindamycin; this inhibition had a greater effect on type C P. gulae than on type A and B isolates. In contrast, the IFN-α formulation inhibited the expression of IL-1ß and COX-2 elicited by type A and B isolates, but not that elicited by type C isolates. Furthermore, periodontal recovery was promoted by the administration of both clindamycin and IFN-α formulation to dogs undergoing periodontal treatment; moreover, this combined treatment reduced the number of FimA genotypes in oral specimens from treated dogs. These results suggest that a combination of clindamycin and IFN-α formulation inhibit P. gulae virulence and thus may be effective for the prevention of periodontal disease induced by P. gulae.

Identification and molecular characterization of Porphyromonas gulae fimA types among cat isolates.

Porphyromonas gulae, a Gram-negative black-pigmented anaerobe, is one of several major periodontal pathogens of animals. P. gulae isolates from dogs have been classified into three genotypes based on a 41-kDa filamentous appendage (FimA) on the cell surface, which is closely related to virulence in periodontal disease. However, other specific bacterial virulence factors contributing to the aggravation of periodontal disease in cats remain elusive. In the present study, we assessed FimA diversity in P. gulae isolates from cats and examined whether this diversity influenced periodontal condition. The putative amino acid sequences of FimA from 15 P. gulae isolates from 13 cats were classified into three genotypes (types A, B, and C), which showed 95-100% identity and similarity to the fimA types in dogs. The type C isolate showed greater adhesion and invasion properties in periodontal ligament fibroblasts as well as stronger inhibition of scratch closure of the cells compared with type A and B isolates. Next, a PCR-based method for identification of fimA genotype was developed and used to analyze 99 oral swab specimens from cats. High fimA type A detection rates were observed regardless of the periodontal condition, whereas types B and C were frequently detected from subjects with moderate and severe periodontitis, respectively. These results suggest that P. gulae isolates from cats can be classified into three types based on fimA genotype, which may be closely related to virulence in periodontitis.