Canine Saliva as a Possible Source of Antimicrobial Resistance Genes

Abstract

While the One Health issues of intensive animal farming are commonly discussed, keeping companion animals is less associated with the interspecies headway of antimicrobial resistance. With the constant advance in veterinary standards, antibiotics are regularly applied in companion animal medicine. Due to the close coexistence of dogs and humans, dog bites and other casual encounters with dog saliva (e.g., licking the owner) are common. According to our metagenome study, based on 26 new generation sequencing canine saliva datasets from 2020 and 2021 reposited in NCBI SRA by The 10,000 Dog Genome Consortium and the Broad Institute within Darwin’s Ark project, canine saliva is rich in bacteria with predictably transferable antimicrobial resistance genes (ARGs). In the genome of potentially pathogenic Bacteroides, Capnocytophaga, Corynebacterium, Fusobacterium, Pasteurella, Porphyromonas, Staphylococcus and Streptococcus species, which are some of the most relevant bacteria in dog bite infections, ARGs against aminoglycosides, carbapenems, cephalosporins, glycylcyclines, lincosamides, macrolides, oxazolidinone, penams, phenicols, pleuromutilins, streptogramins, sulfonamides and tetracyclines could be identified. Several ARGs, including ones against amoxicillin–clavulanate, the most commonly applied antimicrobial agent for dog bites, were predicted to be potentially transferable based on their association with mobile genetic elements (e.g., plasmids, prophages and integrated mobile genetic elements). According to our findings, canine saliva may be a source of transfer for ARG-rich bacteria that can either colonize the human body or transport ARGs to the host bacteriota, and thus can be considered as a risk in the spread of antimicrobial resistance.

Antimicrobial resistance gene lack in tick-borne pathogenic bacteria

“…Countries with at least one sample included in our analysis are shown in Figure 1. Predicted ARG content was analysed with RGI and CARD, a robust pipeline often employed to survey antimicrobial resistance genes in different environments [3][4][5][6][7] . However, as resistance gene presence was rather scarce in the samples analysed in this study, we have included two additional methods for resistance gene prediction to augment our results.…”

“…Francisella showed the highest ratio of samples with at least one ARG (16.3%), however, ARG-positivity was generally very low in the rest of the analysed genera (only 2.2 %). This finding is surprising at first, considering the vast amount of antibiotic pollution and ARG prevalence of the natural and artificial environments [3][4][5][6][7][33][34][35] . The effect of natural environments on the spread of antimicrobial resistance (AMR) is well represented by the fact that wild animals were found to harbour different ARGs 36,37 , even though it might correlate with anthropogenic influence 38,39 .…”

“…While antimicrobial resistance (AMR) is often referred to as one of the main challenges of the 21st century 1 , climate change, urbanization, and globalization may also bring unprecedented changes in public health, namely by affecting the population size and geographical distribution of various disease vectors 2 . Several studies prove the widespread dissemination of antimicrobial resistance genes (ARGs) in various environmental or alimentary sample types [3][4][5][6][7] . Whilst AMR and its underlying causes, ARGs are distributed worldwide and thus may affect human and animal populations globally, vector-borne diseases are also not uncommon.…”

The Use of Antibiotics and Antimicrobial Resistance in Veterinary Medicine, a Complex Phenomenon: A Narrative Review

“…The consistent usage of antibiotics (e.g., prescribed for therapy, misused, or overused) creates a selective pressure on pathogenic bacteria but also on commensal bacteria (e.g., gut or skin microbiota) that can determine the prevalence of antibiotic-resistant bacteria (ARBs) and the spread of resistant bacteria or genes. Plasmids, bacteriophages, or integrative mobile genetic elements facilitate horizontal gene transfer; therefore, it is essential to reduce and to limit the use of antibiotics by following the “principles of responsible and prudent use” in order to preserve their efficacy [ 14 , 15 , 16 ].…”

“…As previously mentioned, Tóth et al [ 16 ] underlined the closeness between humans and companion animals. The study conducted by the authors aimed to (i) detect the ARGs’ content of canine saliva, (ii) attach the ARGs with the bacterial species of origin, and (iii) define the ARGs’ spreading capacity.…”