Microbial Complexity of Oral Cavity of Healthy Dogs Identified by Mass Spectrometry and Next-Generation Sequencing

Abstract

The high complexity of the oral microbiota of healthy dogs and the close exposure of humans to companion animals represent a risk of the transmission of potential zoonotic microorganisms to humans, especially through dog bites, including multidrug-resistant ones. Nonetheless, a limited number of comprehensive studies have focused on the diversity of the microorganisms that inhabit the oral cavities of healthy dogs, particularly based on modern molecular techniques. We investigated bacterial and fungal organisms in the oral cavities of 100 healthy dogs based on a combination of conventional and selective microbiological culture, mass spectrometry (MALDI-TOF MS), and next-generation sequencing. In addition, in vitro antimicrobial susceptibility patterns of isolates and mecA resistance gene were assessed. A total of 213 bacteria and 20 fungi were isolated. Staphylococcus pseudintermedius (40/100 = 40%), α-hemolytic Streptococcus (37/100 = 37%), and Pasteurella stomatis (22/100 = 22%) were the most prevalent bacteria diagnosed by microbiological culture and MALDI-TOF MS, whereas Aspergillus (10/100 = 10%) was the most common fungi identified. Based on next-generation sequencing of selected 20 sampled dogs, Porphyromonas (32.5%), Moraxella (16.3%), Fusobacterium (12.8%), Conchiformibius (9.5%), Bergeyella (5%), Campylobacter (3.8%), and Capnocytophaga (3.4%) genera were prevalent. A high multidrug resistance rate was observed in Staphylococcus pseudintermedius isolates, particularly to azithromycin (19/19 = 100%), penicillin (15/19 = 78.9%), and sulfamethoxazole/trimethoprim (15/19 = 78.9%). In addition, the mecA resistance gene was detected in 6.1% (3/49) of coagulase-positive staphylococci. Here, we highlight the microbial complexity of the oral mucosa of healthy dogs, including potential zoonotic microorganisms and multidrug-resistant bacteria, contributing with the investigation of the microbiota and antimicrobial resistance patterns of the microorganisms that inhabit the oral cavity of healthy dogs.

Species-level characterization of saliva and dental plaque microbiota reveals putative bacterial and functional biomarkers of periodontal diseases in dogs

“…2A ). Notably, members of this bacterial genus are widely reported as predominant commensals of the oral cavity of healthy dogs (Ruparell et al 2020a , Oba et al 2021a , b , 2022 , Portilho et al 2023 ). Thus, this data strengthens the ecological relevance of Porphyromonas species in the salivary microbial ecosystem of dogs.…”

A One Health approach metagenomic study on the antimicrobial resistance traits of canine saliva

“…All ARG-associated bacterial genera identified in the canine salivary samples have been previously described in the canine oral cavity (Porphyromonas spp., Pasteurella spp., Frederiksenia spp., Pseudomonas spp., Conchiformibius spp., Bacteroides spp., Glaesserella spp., Riemerella spp., Escherichia spp., Prevotella spp., Capnocytophaga spp., Klebsiella spp., Mannheimia spp., Histophilus spp., Streptococcus spp., Serratia spp., Haemophilus spp., Enterobacter spp., Clostridioides spp., Parabacteroides spp.) [15][16][17][18][19][20][21][22][23] , or along the canine gastrointestinal tract (Alistipes spp., Lelliottia spp.). 24,25 Wielerella, a genus of Neisseriaceae family has not been previously associated with the canine oral cavity according to our best knowledge.…”