Antimicrobial resistance patterns in dogs with periodontal disease

Canine (Canis lupus familiaris) periodontitis is a severe oral infection affecting majority of populations older than 2 years old characterized by microbial colonization and tissue destruction. This study aimed to investigate the antibiotic resistance patterns of bacteria isolated from the alveoli of extracted teeth in dogs with advanced periodontitis. Traditional bacteriological plating methods and next generation sequencing technologies were performed to analyse the microbiota and antimicrobial resistance. The predominant bacteria detected by NGS were Porphyromonas gulae, Prevotella spp., Tannerella forsythia, Porphyromonas crevioricanis, Porphyromonas cangingivalis. Traditional plating methods most frequently identified Pasteurella spp., Streptococcus spp. and Neisseria spp. Antibiotic resistance testing performed by E-test on isolated bacteria revealed clinical resistance to ampicillin, doxycycline, sulfamethoxazole-trimethoprim, ciprofloxacin and chloramphenicol. Genetic markers for resistance to beta-lactams (OXA347), tetracyclines (TetM, TetQ, TetW, Tet32 and TetO) aminoglycosides (AadE, AadS), macrolides (ErmF, Erm39, Mef(En2)) and colistin (Mcr1) were detected using next generation metagenomic sequencing. The presence of antimicrobial resistance to critically important antimicrobial classes for humans and animals’ bacteria in dogs with periodontal disease highlights the potential to public health risk, because these bacteria can be transmitted to humans through dog bites or even daily contact. Although the study highlights the importance of antimicrobial susceptibility testing before prescribing antibiotics for dogs, it should be kept in mind, that some of the pathogens located in periodontal pockets are still unculturable. By this reason, etiological agents detected solely by classical bacteriological methods may be underestimated, whereas incorrect prescription of antibiotics for periodontal disease treatment can increase resistance problem in small animal medicine. Prophylaxis of periodontal disease is a key element keeping an appropriate oral health in animals, thus preventing the necessity for radical treatment and excessive usage of antibiotics.