Phylogenetic analysis of members of the genus Porphyromonas and description of Porphyromonas cangingivalis sp. nov. and Porphyromonas cansulci sp. nov

Porphyromonas levii - A Boon for Periodontists?

The majority of species previously categorized as Bacteroides have been reassigned into new genera. Bacteroides levii (Holdeman, Cato, and Mooretaxonomic)'s status has remained uncertain. This species shares a high degree of similarity with members of the genus Porphyromonas based on biochemical, chemical, and comparative 16s rRNA sequence analysis. As a result, Bacteroides levii (Holdeman, Cato, and Moore) was reclassified as Porphyromonas levii comb. now under the genus Porphyromonas.

Pseudomonas spp. in Canine Otitis Externa

Canine otitis externa (OE) is a commonly diagnosed condition seen in veterinary practice worldwide. In this review, we discuss the mechanisms of the disease, with a particular focus on the biological characteristics of Pseudomonas aeruginosa and the impact that antibiotic resistance has on successful recovery from OE. We also consider potential alternatives to antimicrobial chemotherapy for the treatment of recalcitrant infections. P. aeruginosa is not a typical constituent of the canine ear microbiota, but is frequently isolated from cases of chronic OE, and the nature of this pathogen often makes treatment difficult. Biofilm formation is identified in 40-95% of P. aeruginosa from cases of OE and intrinsic and acquired antibiotic resistance, especially resistance to clinically important antibiotics, highlights the need for alternative treatments. The role of other virulence factors in OE remains relatively unexplored and further work is needed. The studies described in this work highlight several potential alternative treatments, including the use of bacteriophages. This review provides a summary of the aetiology of OE with particular reference to the dysbiosis that leads to colonisation by P. aeruginosa and highlights the need for novel treatments for the future management of P. aeruginosa otitis.

Phylogenomic analysis of the Porphyromonas gingivalis - Porphyromonas gulae duo: approaches to the origin of periodontitis

Porphyromonas gingivalis is an oral human pathogen associated with the onset and progression of periodontitis, a chronic immune-inflammatory disease characterized by the destruction of the teeth-supporting tissue. P. gingivalis belongs to the genus Porphyromonas, which is characterized by being composed of Gram-negative, asaccharolytic, non-spore-forming, non-motile, obligatory anaerobic species, inhabiting niches such as the oral cavity, urogenital tract, gastrointestinal tract and infected wound from different mammals including humans. Among the Porphyromonas genus, P. gingivalis stands out for its specificity in colonizing the human oral cavity and its keystone pathogen role in periodontitis pathogenesis. To understand the evolutionary process behind P. gingivalis in the context of the Pophyoromonas genus, in this study, we performed a comparative genomics study with publicly available Porphyromonas genomes, focused on four main objectives: (A) to confirm the phylogenetic position of P. gingivalis in the Porphyromonas genus by phylogenomic analysis; (B) the definition and comparison of the pangenomes of P. gingivalis and its relative P. gulae; and (C) the evaluation of the gene family gain/loss events during the divergence of P. gingivalis and P. gulae; (D) the evaluation of the evolutionary pressure (represented by the calculation of Tajima-D values and dN/dS ratios) comparing gene families of P. gingivalis and P. gulae. Our analysis found 84 high-quality assemblies representing P. gingivalis and 14 P. gulae strains (from a total of 233 Porphyromonas genomes). Phylogenomic analysis confirmed that P. gingivalis and P. gulae are highly related lineages, close to P. loveana. Both organisms harbored open pangenomes, with a strong core-to-accessory ratio for housekeeping genes and a negative ratio for unknown function genes. Our analyses also characterized the gene set differentiating P. gulae from P. gingivalis, mainly associated with unknown functions. Relevant virulence factors, such as the FimA, Mfa1, and the hemagglutinins, are conserved in P. gulae, P. gingivalis, and P. loveana, suggesting that the origin of those factors occurred previous to the P. gulae - P. gingivalis divergence. These results suggest an unexpected evolutionary relationship between the P. gulae - P. gingivalis duo and P. loveana, showing more clues about the origin of the role of those organisms in periodontitis.

Porphyromonas spp. have an extensive host range in ill and healthy individuals and an unexpected environmental distribution: A systematic review and meta-analysis

Studies on the anaerobic bacteria Porphyromonas, mainly focused on P. gingivalis, have revealed new bacterial structures, metabolic pathways, and physiologic functionalities. Porphyromonas are mainly described as being associated with mammals and involved in chronic oral infections and secondary pathologies such as cancers or neurodegenerative diseases. In this review, we collected and analyzed information regarding Porphyromonas isolation sites and associated conditions and showed that Porphyromonas are detected in numerous pristine and anthropic environments and that their host range appears wider than previously believed, including aquatic animals, arthropods, and birds, even if their predominant hosts remain humans, pets, and farm animals. Our analyses also revealed their presence in multiple organs and in a substantial proportion of healthy contexts. Overall, the growing numbers of microbiota studies have allowed unprecedented advances in the understanding of Porphyromonas ecology but raise questions regarding their phylogenic assignment. In conclusion, this systematic and meta-analysis provides an overview of current knowledge regarding Porphyromonas ecological distribution and encourages additional research to fill the knowledge gaps to better understand their environmental distribution and inter- and intra-species transmission.

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

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.

Dental Plaque Flora of the Dog with Reference to Fastidious and Anaerobic Bacteria Associated with Bites

Animal bite wounds are amongst the most common types of traumatic injuries in humans. The organisms isolated from these wounds generally reflect the oral flora of the biting animal and may be fastidious in nature and difficult to identify. This study was undertaken to determine the prevalence of Eikenella corrodens, Actinobacillus actinomycetemcomitans, Porphyromonas and Prevotella spp. in supragingival dental plaque collected from the right maxillary canine and carnassial teeth and the right mandibular canine tooth of dogs. In part one of the study, 30 dogs were used. E. corrodens was found in 62% of these dogs and 44% of individual plaque samples. A. actinomycetemcomitans was not detected in any of the dogs sampled. In pan two, 34 dogs were used to determine the prevalence of the black pigmented anaerobic bacilli (Porphyromonas and Prevotella spp.). Porphyromonas gingivalis was present in 68% of these dogs and 47% of individual plaque samples. Prevotella intermedia was present in 44% of the dogs and 23% of individual plaque samples. The recently described Porphyromonas canoris, Porphyromonas salivosa, Porphyromonas cangingivalis, Porphyromonas cansulci, Porphyromonas crevioricanis and Prevotella denticola species were isolated from only 9%, 6%, 3%, 3%, 3% and 3% of dogs respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. In conclusion, black-pigmented anaerobic bacilli were isolated from 91% of the animals sampled and therefore constitute a significant risk with respect to bite wound infections. It is also suggested that the prevalence of E. corrodens in wound infections has been underestimated in previous reports because of use of inappropriate techniques for detecting this organism.

Antibacterial effects of sodium tripolyphosphate against Porphyromonas species associated with periodontitis of companion animals

Porphyromonas species are closely associated with companion animal periodontitis which is one of the most common diseases in dogs and cats and leads to serious systemic diseases if left untreated. In this study, we evaluated the antimicrobial effects and mode of action of sodium tripolyphosphate (polyP3, Na₅P₃O₁₀), a food additive with proven safety, using three pathogenic Porphyromonas species. The minimum inhibitory concentrations (MICs) of polyP3 against Porphyromonas gulae, Porphyromonas cansulci, and Porphyromonas cangingivalis were between 500 and 750 mg/L. PolyP3 significantly decreased viable planktonic cells as well as bacterial biofilm formation, even at sub-MIC concentrations. PolyP3 caused bacterial membrane disruption and this effect was most prominent in P. cangingivalis, which was demonstrated by measuring the amount of nucleotide leakage from the cells. To further investigate the mode of action of polyP3, high-throughput whole-transcriptome sequencing was performed using P. gulae. Approximately 30% of the total genes of P. gulae were differentially expressed by polyP3 (> 4-fold, adjusted p value < 0.01). PolyP3 influenced the expression of the P. gulae genes related to the biosynthesis of thiamine, ubiquinone, and peptidoglycan. Collectively, polyP3 has excellent antibacterial effects against pathogenic Porphyromonas species and can be a promising agent to control oral pathogenic bacteria in companion animals.

The corrosion process caused by the activity of the anaerobic sporulated bacterium Clostridium celerecrescens on API XL 52 steel

The microbial corrosion of oil and gas pipes is one of the problems occurring in the oil industry. Various mechanisms explaining microbial corrosion have been demonstrated. Commonly, biocorrosion is attributed to sulfate-reducing bacteria. Also, it has recently been reported that microbial species can connect their electron transport system to metal electrodes. In this research, two spore-forming bacteria isolated in different years from a gas pipeline were identified by biochemical techniques and by 16S rDNA amplification, sequencing, and comparison with the NCBI database. Isolates were also compared between them using molecular techniques as the restriction patterns, unique for 16S rDNA (ARDRA), and the profile of the amplified bit from the genomic DNA, using an unspecific primer (RAPD). The results obtained showed that both isolates corresponded to Clostridium celerecrescens with a 99% similarity according to the sequence reported on the NCBI database. Also, the ARDRA and RAPD electrophoretic profiles of both strains were identical, and no plasmids were found in the strains. Thus, it can be settled that this bacterium is persistent in the environment prevailing in gas pipelines. Also, it was demonstrated that the bacterial secretion of organic acids contributes to the pitting and general biocorrosion of API XL 52 steel. The rates of corrosion obtained, approximately after 40 days, were correlated with the presence and metabolic activity of C. celerecrescens on the metallic surfaces.

Analysis of 1,000 Type-Strain Genomes Improves Taxonomic Classification of Bacteroidetes

Although considerable progress has been made in recent years regarding the classification of bacteria assigned to the phylum Bacteroidetes, there remains a need to further clarify taxonomic relationships within a diverse assemblage that includes organisms of clinical, piscicultural, and ecological importance. Bacteroidetes classification has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees and a limited number of phenotypic features. Here, draft genome sequences of a greatly enlarged collection of genomes of more than 1,000 Bacteroidetes and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa proposed long ago such as Bacteroides, Cytophaga, and Flavobacterium but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which can be considered valuable taxonomic markers. We detected many incongruities when comparing the results of the present study with existing classifications, which appear to be caused by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. The few significant incongruities found between 16S rRNA gene and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences and the impediment in using ordinary bootstrapping in phylogenomic studies, particularly when combined with too narrow gene selections. While a significant degree of phylogenetic conservation was detected in all phenotypic characters investigated, the overall fit to the tree varied considerably, which is one of the probable causes of misclassifications in the past, much like the use of plesiomorphic character states as diagnostic features.

Evaluation of Subgingival Bacteria in the Dog and Susceptibility to Commonly Used Antibiotics

The aim of the present investigation was to evaluate the subgingival aerobic and anaerobic flora of 13 dogs with periodontal disease and the susceptibility of these bacteria to antibiotics currently approved in Italy for treatment of canine infections. Of the anaerobic bacteria, Bacteroides fragilis was most frequently isolated, followed by Peptostreptococcus + Porphyromonas gingivalis and Prevotella intermedia. Of the aerobic bacteria, α-hemolytic Streptococcus was most frequently isolated, often associated with Escherichia coli or Pasteurella multocida. Resistance of anaerobic and aerobic bacteria to various antibiotics was generally high. Anaerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, doxycycline, and erythromycin; aerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, erythromycin, gentamycin, and sulfa-trimethoprim. Bacteroides fragilis was resistant to all of the antibiotics tested. The emerging worldwide problem of bacterial resistance to antibiotics resulting from overuse and misuse of antibiotics is discussed.

Draft Genome Sequences of Porphyromonas crevioricanis JCM 15906T and Porphyromonas cansulci JCM 13913T Isolated from a Canine Oral Cavity

Here, we report the draft genome sequences of Porphyromonas crevioricanis JCM 15906^T and Porphyromonas cansulci JCM 13913^T, which were isolated from a canine oral cavity and were recently united under the single species P. crevioricanis. These two genome sequences are very similar, and yet a high degree of genome rearrangements is observed.

Porphyromonas crevioricanis is an earlier heterotypic synonym of Porphyromonas cansulci and has priority

A DNA–DNA hybridization experiment was carried out to clarify the relationship between Porphyromonas crevioricanis and Porphyromonas cansulci . The taxonomic standing of these two species was unclear so far because of the high 16S rRNA gene sequence similarity value (99.9 %). The DNA–DNA relatedness values between P. crevioricanis JCM 15906T and P. cansulci JCM 13913T were above 91 % (91–99 %). In addition, P. crevioricanis JCM 15906T exhibited high hsp60 gene sequence similarity with P. cansulci JCM 13913T (100 %). The hsp60 gene sequence analysis and the DNA–DNA relatedness values demonstrated that P. crevioricanis JCM 15906T and P. cansulci JCM 13913T are a single species. Based on these data, we propose Porphyromonas cansulci as a later heterotypic synonym of Porphyromonas crevioricanis .

The canine oral microbiome

Determining the bacterial composition of the canine oral microbiome is of interest for two primary reasons. First, while the human oral microbiome has been well studied using molecular techniques, the oral microbiomes of other mammals have not been studied in equal depth using culture independent methods. This study allows a comparison of the number of bacterial taxa, based on 16S rRNA-gene sequence comparison, shared between humans and dogs, two divergent mammalian species. Second, canine oral bacteria are of interest to veterinary and human medical communities for understanding their roles in health and infectious diseases. The bacteria involved are mostly unnamed and not linked by 16S rRNA-gene sequence identity to a taxonomic scheme. This manuscript describes the analysis of 5,958 16S rRNA-gene sequences from 65 clone libraries. Full length 16S rRNA reference sequences have been obtained for 353 canine bacterial taxa, which were placed in 14 bacterial phyla, 23 classes, 37 orders, 66 families, and 148 genera. Eighty percent of the taxa are currently unnamed. The bacterial taxa identified in dogs are markedly different from those of humans with only 16.4% of oral taxa are shared between dogs and humans based on a 98.5% 16S rRNA sequence similarity cutoff. This indicates that there is a large divergence in the bacteria comprising the oral microbiomes of divergent mammalian species. The historic practice of identifying animal associated bacteria based on phenotypic similarities to human bacteria is generally invalid. This report describes the diversity of the canine oral microbiome and provides a provisional 16S rRNA based taxonomic scheme for naming and identifying unnamed canine bacterial taxa.

Molecular identification of bacteria associated with canine periodontal disease

Periodontal disease is one of the most common diseases of adult dogs, with up to 80% of animals affected. The aetiology of the disease is poorly studied, although bacteria are known to play a major role. The purpose of this study was to identify the bacteria associated with canine gingivitis and periodontitis and to compare this with the normal oral flora. Swabs were obtained from the gingival margin of three dogs with gingivitis and three orally healthy controls, and subgingival plaque was collected from three dogs with periodontitis. Samples were subjected to routine bacterial culture. The prevalent species identified in the normal, gingivitis and periodontitis groups were uncultured bacterium (12.5% of isolates), Bacteroides heparinolyticus/Pasteurella dagmatis (10.0%) and Actinomyces canis (19.4%), respectively. Bacteria were also identified using culture-independent methods (16S rRNA gene sequencing) and the predominant species identified were Pseudomonas sp. (30.9% of clones analysed), Porphyromonas cangingivalis (16.1%) and Desulfomicrobium orale (12.0%) in the normal, gingivitis and periodontitis groups, respectively. Uncultured species accounted for 13.2%, 2.0% and 10.5%, and potentially novel species for 38.2%, 38.3% and 35.3%, of clones in the normal, gingivitis and periodontitis groups, respectively. This is the first study to use utilise culture-independent methods for the identification of bacteria associated with this disease. It is concluded that the canine oral flora in health and disease is highly diverse and also contains a high proportion of uncultured and, in particular, potentially novel species.

Usefulness of the hsp60 gene for the identification and classification of Gram-negative anaerobic rods

The hsp60 gene sequences were determined for 121 strains of Gram-negative anaerobic rods, including the genera Bacteroides, Barnesiella, Butyricimonas, Odoribacter, Parabacteroides, Paraprevotella, Porphyromonas, Prevotella and Tannerella. The mean pairwise hsp60 gene sequence similarity (73.8–97.1 %) between species in each genus, except for the genus Tannerella that comprises one species, was significantly less than that of the 16S rRNA gene sequence (88.3–96.3 %). Only pairwise hsp60 gene sequence similarity (97.1 %) of the genus Paraprevotella was higher than that of the 16S rRNA gene sequence (93.8 %). Each genus formed a distinct clade in the phylogenetic analysis of the hsp60 gene sequence as well as the 16S rRNA gene sequence. The phylogenetic analysis indicated a higher evolutionary rate for the hsp60 gene sequence than the 16S rRNA gene sequence, especially in the genera Porphyromonas and Prevotella. This study suggests that the hsp60 gene is a useful alternative phylogenetic marker for the identification and classification of a broad range of Gram-negative anaerobic rods.

Approaches to the study of the systematics of anaerobic, gram-negative, non-sporeforming rods: current status and perspectives

The present article gives an overview of recent taxonomic changes among the Gram-negative, anaerobic rods, briefly highlighting areas where the biology and ecology have a bearing on recent nomenclatorial changes. The focus is among the genera Bacteroides, Prevotella, Porphyromonas, Leptotrichia, Dysgonomonas, Fusobacterium and the Synergistes group and additionally demonstrates the value of conserved indels and group-specific proteins for identifying and circumscribing many of these taxa and the Bacteroidetes-Chlorobi species in general.

Butyricimonas synergistica gen. nov., sp. nov. and Butyricimonas virosa sp. nov., butyric acid-producing bacteria in the family 'Porphyromonadaceae' isolated from rat faeces

Two bacterial strains, designated MT01(T) and MT12(T), isolated from rat faeces were characterized by using a polyphasic taxonomic approach that included analysis of their phenotypic and biochemical features, cellular fatty acid profiles, menaquinone profiles and phylogeny based on 16S rRNA gene sequences. The 16S rRNA gene sequence analysis showed that these strains were members of the family 'Porphyromonadaceae'. The strains shared 94 % 16S rRNA gene sequence similarity with each other and were related to Odoribacter splanchnicus NCTC 10825(T) (86-87 % sequence similarity). The strains consisted of obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. Growth of the strains was inhibited on medium containing 20 % bile. The two strains produced significant levels of butyric and isobutyric acids as end products from glucose. Although the major cellular fatty acid of these two strains and O. splanchnicus JCM 15291(T) was iso-C(15 : 0), strains MT01(T) and MT12(T) showed a higher level of iso-C(15 : 0) (66 and 74 %, respectively) than did O. splanchnicus JCM 15291(T) (48 %). In addition, the ratios of iso-C(15 : 0) to anteiso-C(15 : 0) in whole-cell methanolysates of the two isolates were very much higher than that of O. splanchnicus JCM 15291(T). The major menaquinone of the isolates was MK-10. This menaquinone composition was different from those of other genera of the family 'Porphyromonadaceae', such as Barnesiella (predominant menaquinones: MK-11 and MK-12), Odoribacter (MK-9), Paludibacter (MK-8), Parabacteroides (MK-9 and MK-10), Porphyromonas (MK-9 and MK-10) and Tannerella (MK-10 and MK-11). Menaquinone composition is therefore an important chemotaxonomic characteristic of these micro-organisms. Strains MT01(T) and MT12(T) have DNA G+C contents of 46 mol%. On the basis of these data, strains MT01(T) and MT12(T) represent two novel species of a novel genus, for which the names Butyricimonas synergistica gen. nov., sp. nov. and Butyricimonas virosa sp. nov., respectively, are proposed. The type strains of B. synergistica and B. virosa are MT01(T) (=JCM 15148(T) =CCUG 56610(T)) and MT12(T) (=JCM 15149(T)=CCUG 56611(T)), respectively.

The microbiome of the cloacal openings of the urogenital and anal tracts of the tammar wallaby, Macropus eugenii

The bacterial diversity of the openings of the urogenital and anal tracts of the adult female tammar wallaby, Macropus eugenii, was determined in order to ascertain whether the physical proximity of the openings of these tracts within the cloaca affected the two populations of bacteria. Terminal restriction fragment length polymorphism (T-RFLP) analyses of 42 wallabies identified 81 different terminal fragments, indicative of diverse and complex microbiomes at these anatomical locations. Subsequent amplified rDNA restriction analysis (ARDRA) identified 72 phylotypes from the urogenital tract and 50 from the anal tract. Twenty-two of these phylotypes were common to both tracts. Phylogenetic analysis of sequenced 16S rDNA showed that 83 % of the phylotypes were unidentified species based on the premise that any sequence possessing <97 % homology to a known bacterial species or phylotype was novel. Thus, despite the close proximity of the openings of the urogenital and anal tracts within the cloaca, the two sites retained a diverse range of distinct bacteria, with only a small percentage of overlapping species.

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

Porphyromonas species are frequently isolated from the oral cavity and are associated with periodontal disease in both animals and humans. Black, pigmented Porphyromonas spp. isolated from the gingival margins of selected wild and captive Australian marsupials with varying degrees of periodontal disease (brushtail possums, koalas and macropods) were compared phylogenetically to Porphyromonas strains from non-marsupials (bear, wolf, coyote, cats and dogs) and Porphyromonas gingivalis strains from humans using 16S rRNA gene sequence analysis. The results of the phylogenetic analysis identified three distinct groups of strains. A monophyletic P. gingivalis group (Group 1) contained only strains isolated from humans and a Porphyromonas gulae group (Group 2) was divided into three distinct subclades, each containing both marsupial and non-marsupial strains. Group 3, which contained only marsupial strains, including all six strains isolated from captive koalas, was genetically distinct from P. gulae and may constitute a new Porphyromonas species.

Management of periodontal disease: understanding the options

Periodontal disease is the most common disease occurring in domestic dogs and cats, and local severity and the impact on the rest of the body are reasons why all companion animal patients should receive an oral examination every time they are seen. This article provides the background information on how an effective periodontal management program can be tailored for each patient.

Pigmented-anaerobic bacteria associated with canine periodontitis

The etiology of human periodontal disease has been the focus of considerable research, yet relatively little is known about the causative agents of companion animal periodontitis. In humans, Porphyromonas gingivalis, a black-pigmented anaerobic bacteria (BPAB), has been implicated as the primary periopathogen. It has been demonstrated that BPAB are also found in companion animal periodontal pockets. While some animal BPAB have been individually identified, a study to identify the most frequently isolated subgingival BPAB has not been completed using genetic tools. The objective of this work was to identify the types and relative frequencies of pigmented anaerobic bacteria found in the periodontal pockets of dogs. Porphyromonas salivosa, Porphyromonas denticanis (a novel species) and Porphyromonas gulae were found to be the most frequently isolated BPAB associated with canine periodontitis.

Measurement of peptidase activity and evaluation of effectiveness of administration of minocycline for treatment of dogs with periodontitis

OBJECTIVE

To determine clinical, enzymatic, and microbiologic effects of controlled-release localized administration of minocycline on dogs with periodontitis.

ANIMALS

Five adult Beagles with periodontitis.

PROCEDURE

After tooth scaling and root planing, 2 treatment, 1 placebo, and 1 control site were selected for each dog. Treatment sites (n = 10) received a periodontal formulation of minocycline hydrochloride, placebo sites (5) received ointment without minocycline, and control sites (5) did not receive ointment. Treatments were administered 4 times at weekly intervals. Peptidase activity and clinical and microbiologic effects were evaluated and compared among sites for 17 weeks.

RESULTS

Bleeding of the gums on probing (BOP) and pocket depth (PD) improved at the treatment site and were maintained for 13 weeks after treatment. However, BOP and PD in placebo and control sites increased from weeks 9 to 17 Peptidase activity in the periodontal pocket decreased noticeably from week 1 to 17, compared with baseline values for the treatment site. However, peptidase activity for placebo and control sites increased and were above baseline values on week 9 and week 13, respectively. Total bacterial counts decreased by 90% for treatment sites and remained at that value for 13 weeks. However, for placebo and control sites, bacterial counts increased and reached the baseline value on week 17.

CONCLUSIONS AND CLINICAL RELEVANCE

Increased peptidase activity is correlated with the progression of periodontitis in dogs. Treatment with minocycline, using a localized delivery system, was effective in dogs for at least 13 weeks after cessation of drug administration.

Periodontal disease in dogs. Etiopathogenesis, prevalence, and significance

Periodontal disease is very common and often very severe in dogs. It is caused by accumulation of bacterial plaque, particularly Gram-negative anaerobic rods. Tissue destruction results from autodegradation induced by the continuing inflammatory response. Small dogs are particularly at risk. Prevention by retarding accumulation of plaque is the key concept.

Prevalence of Porphyromonas and Prevotella species in the dental plaque of dogs

The prevalence and populations of Porphyromonas and Prevotella species were determined in three samples of dental plaque from each of 34 healthy dogs. Porphyromonas gingivalis was present in 68 per cent of the dogs and 47 per cent of the plaque samples. The counts of P gingivalis increased with age (P < 0.1), the amount of plaque (P < 0.05) and the degree of gingivitis (P < 0.1). Prevotella intermedia was present in 44 per cent of the dogs and 23 per cent of the plaque samples. The counts of P intermedia were correlated with the amount of plaque (P < 0.05) and the degree of gingivitis (P < 0.1). Porphyromonas canoris, P salivosa, P cangingivalis, P cansulci, P crevioricanis and Prevotella denticola were isolated from only 9, 6, 3, 3, 3 and 3 per cent of the dogs, respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. There was a highly significant (P < 0.001) correlation between the amount of plaque, the extent of gingivitis and the age of the dog.

Rapid characterization of periodontal bacterial isolates by using fluorogenic substrate tests

Eighty-nine species of subgingival bacteria, represented by 121 reference strains and 892 patient isolates, including gram-negative, gram-positive, aerobic, facultatively anaerobic, microaerophilic, and anaerobic species, were characterized with a panel of fluorogenic, 4-methylumbelliferyl-linked substrate tests. Identifications of all patient isolates were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins relative to reference strains. Characteristic profiles of positive fluorogenic reactions differentiated most of the species, including five Porphyromonas species, six pigmenting and five nonpigmenting Prevotella species, Bacteroides forsythus, three Capnocytophaga species, six Actinomyces species, four Propionibacterium species, and eight Streptococcus species. Two mannoside isomers differentiated Actinomyces israelii and Actinomyces gerencseriae. In addition to Porphyromonas gingivalis, B. forsythus, and Capnocytophaga species, Fusobacterium alocis, Actinomyces odontolyticus, Actinomyces meyeri, and Bifidobacterium dentium were all positive for so-called trypsin-like activity. Fusobacterium nucleatum, Eikenella corrodens, Actinobacillus actinomycetemcomitans, and Campylobacter species were nonreactive with the carbohydrate-based substrates tested. Fluorogenic substrate tests provided a sensitive and simple method for biochemical characterization that could presumptively identify to species level most subgingival isolates within 4 h. The method was ideal for rapidly obtaining presumptive identifications of isolates prior to confirming identifications by definitive methods, such as SDS-PAGE.