Evaluation of the most important anaerobic bacteria in the pathogenesis of canine periodontitis

SUMMARY Background: The oral hygiene in dogs depends mostly on the quality of con sumed food and plaque removal performed by the owner. In neglected cases severe, irreversible periodontitis with pockets containing anaerobic bacterial flora could evolve in months or years. Objectives: The aim of this study was to isolate Porphyromonas spp. and Prevotella spp. from subgingival samples taken from dogs with moderate to severe clinical periodontal diseases, and the susceptibility testing of these strains, with special regard to pradofloxacin. Materials and Methods: Samples for the study were collected while the dogs were under general anaesthesia. We collected 150 periodontal samples from 59 dogs. The samples were shipped directly to Duo-Bakt Laboratórium, Budapest, Hungary. At Duo-Bakt Laboratórium the samples were inoculated on a Wilkins– Chalgren (incl. 8% sheep blood) plate and on another plate, which included nalidixic acid and colistin. All plates were incubated in an anaerobic environment at 35 °C for 5–7 days, after which all pigmented colonies and the suspected non-pigmented Prevotella spp. colonies were selected. The identification was performed by analysing the morphology of the colonies, pigmentation, and the results of the presumptive tests. Final identification was performed by MALDITOF-mass spectroscopy. Results and Discussion: During the study, 74 Porphyromonas and 2 Prevotella isolates were isolated, identified and transported to Laboklin, Bad Kissingen, Germany for antibacterial susceptibility testing. According to our results, pradofloxacin could be a promising choice in the treatment of periodontitis as in most cases the MIC values were under 0.1 mg/l. Based on our clinical experiences and the MIC values, amoxicillin-clavulanic-acid is still an appropriate antibiotic for the treatment of periodontal diseases in dogs, however, resistant strains to clindamycin and metronidazole were found. These antibacterial susceptibility test results could help veterinarians to create the best protocols for the treatment of periodontitis