Bacterial profiles and antibiograms of the bacteria isolated of the exposed pulps of dog and cheetah canine teeth

Abstract

Objectives: The aims of this study was to investigate the RC microbiota in CCF canine teeth in the domestic dogs (Canis familiaris) and cheetahs (Acinonyx jubatus), identify the possible factors related to the presence of aerobic or anaerobic bacteria and evaluate and evaluate antibiotic susceptibility of bacteria isolated. Animals: Thirty nine animals suffering from CCF of their canine teeth were included in this study, of which 20 were dogs and 19 were cheetahs. Procedures: Evaluation of the oral cavity of animals while under general anaesthesia was performed and those without necrotic pulps or those that had received antibiotic therapy in the previous two weeks were excluded. Microbial samples were taken from 63 RC of which 27 were from dogs and 36 were from cheetahs. Strict anaerobic and aerobic techniques were used in parallel for plating, incubation and identification of the bacteria isolated in this manner. In an attempt to evaluate the sensitivity of the culture media and anaerobic technique used, additional samples were collected after the samples for bacterial isolation had been taken from the last eight pulps. These comprised those from six cheetahs and two dogs and were analysed using culture techniques and an initial screening with the 16S rRNA-specific PCR. Results: • Dogs: A total of 49 cultivable isolates were recovered belonging to 19 different bacterial species and 13 different genera. Individual RC yielded a maximum of four bacterial species. Of the bacterial isolates, 4.08 % were strict anaerobes, being represented by Clostridium acetobulitycum (2.04 %) and Prevotella melalinogenica (2.04 % ). The incidence of aerobic bacteria and facultative anaerobic bacteria in this study were 18.36 % and 77.56 %respectively of all the bacterial isolates. Of these Pasteurella multocida ( 10.20 % ), Corynebacterium spp. (10.20 %), Moraxella spp. (8.17 %), Bacillus spp. (6.12 %), Aeromonas salmonicida (6.12 %), Escherichia coli (6.12 %) and Pseudomonas aeruginosa (6.12 %) were the bacteria most frequently isolated. In summary, the RC microflora was found to be predominantly Gram negative facultative anaerobic microorganisms. The antibiotic agents that showed the highest efficacy in vitro against the different bacteria isolates were Enrofloxacin (85.21 % ), Gentamicin (92.39 %), Chloramphenicol (89.13 %). • Cheetahs: A total of 59 cultivable isolates, belonging to 19 different microbial species and 13 different genera were recovered from 36 RC sampled. Thirty-two (54.49 %) of the cultivable isolates were Gram positive while 27 (45.71 %) were Gram negative. Individual root canals each yielded a maximum of six species. Four RC had no cultivable bacteria. The bacterial micro flora recovered from the RC of the animals showed a higher number of facultative anaerobes (62.72 % of all the bacterial isolates). Aerobic isolates were 28.81 %, and strict anaerobes 8.47 % of all the isolates. The latter species comprised Clostridium sordelli (5.08 % ), and Clostridium septicum (3.38 % ). The species with the highest isolation frequency were Bacillus spp. (22.13 %), Pasteurella multocida (10.16 %), Corynebacterium spp. (8.47 %), Enterococcus spp. (8.47 %), Moraxella spp. (8.47 %) and Pseudomonas aeruginosa (5.25 %). In summary, the bacteria isolated from the RC were Gram positive facultative anaerobic bacteria. The antibiotics, which showed the highest efficacy in vitro against the different bacteria isolates, were Enrofloxacin (91.96 %), Gentamicin (86.37 %) and Orbifloxacin (86.28 %). • Nucleic Acid-Base detection: In dogs, Gram negative and Gram positive bacterial species were equally represented. Anaerobic bacterial species predominated at 83.3 % (5/6) of the species detected. On the other hand, in cheetahs, the bacterial species isolated by the PCR method showed a prevalence of anaerobic bacteria (60.8 %, 14/23), while facultative anaerobes were isolated in 30.2 % (7 /23) of cases and aerobic bacteria in 8.6 % (2/23). Conclusions and Clinical Relevance: This study has indicated that the microbial flora in any single infected RC is much more diverse than it has been shown using cultural techniques alone and can contain potentially uncultivable bacterial species. Some of these species may represent potentially new phylotypes, which may be involved in endodontic infections and ultimatelyin periradicular periodontitis, and should therefore be considered in any future studies involved in defining endodontic pathogens. Copyright