Activity of Pradofloxacin against Porphyromonas and Prevotella spp. Implicated in Periodontal Disease in Dogs: Susceptibility Test Data from a European Multicenter Study

Collaborating veterinarians from five European countries collected subgingival bacterial samples from dogs exhibiting clinical periodontal disease. Sterile endodontic paper points were used for collection of the samples, which were transported to a central laboratory for susceptibility testing. Anaerobic bacteria were isolated andPorphyromonas andPrevotella isolates identified to the species level; susceptibility to pradofloxacin and metronidazole was determined using the CLSI agar dilution methodology. A total of 630 isolates, 310 ofPorphyromonas spp. and 320 ofPrevotella spp., were isolated. Pradofloxacin MIC data for all isolates were in the range of ≤0.016 to 1 μg/ml, the overall MIC50 was 0.062, and the overall MIC90 was 0.25 μg/ml. There were no differences in activity againstPorphyromonas andPrevotella isolates or in the pradofloxacin susceptibility distributions from the different European countries. All isolates were within the wild-type distribution and were fully susceptible to pradofloxacin. Metronidazole was also highly active against these strains: 316 of 320Prevotella strains (98.8%) and 309 of 310Porphyromonas strains (99.7%) were susceptible (MICs of ≤8 μg/ml). However, threePrevotella strains had intermediate metronidazole susceptibility (MICs of 16 μg/ml), while onePrevotella and onePorphyromonas strain were metronidazole resistant (MICs of 128 and 256 μg/ml, respectively). Pradofloxacin, a novel broad-spectrum fluoroquinolone, demonstrates a high degree of antianaerobic activity against strains isolated from clinical cases of periodontal disease and shows activity against metronidazole-resistant isolates. The broad-spectrum activity of pradofloxacin makes it a suitable candidate for the treatment of periodontal disease in dogs.