The Skin Microbiome in Healthy and Allergic Dogs

Abstract

BackgroundChanges in the microbial populations on the skin of animals have traditionally been evaluated using conventional microbiology techniques. The sequencing of bacterial 16S rRNA genes has revealed that the human skin is inhabited by a highly diverse and variable microbiome that had previously not been demonstrated by culture-based methods. The goals of this study were to describe the microbiome inhabiting different areas of the canine skin, and to compare the skin microbiome of healthy and allergic dogs.Methodology/Principal FindingsDNA extracted from superficial skin swabs from healthy (n = 12) and allergic dogs (n = 6) from different regions of haired skin and mucosal surfaces were used for 454-pyrosequencing of the 16S rRNA gene. Principal coordinates analysis revealed clustering for the different skin sites across all dogs, with some mucosal sites and the perianal regions clustering separately from the haired skin sites. The rarefaction analysis revealed high individual variability between samples collected from healthy dogs and between the different skin sites. Higher species richness and microbial diversity were observed in the samples from haired skin when compared to mucosal surfaces or mucocutaneous junctions. In all examined regions, the most abundant phylum and family identified in the different regions of skin and mucosal surfaces were Proteobacteria and Oxalobacteriaceae. The skin of allergic dogs had lower species richness when compared to the healthy dogs. The allergic dogs had lower proportions of the Betaproteobacteria Ralstonia spp. when compared to the healthy dogs.Conclusions/SignificanceThe study demonstrates that the skin of dogs is inhabited by much more rich and diverse microbial communities than previously thought using culture-based methods. Our sequence data reveal high individual variability between samples collected from different patients. Differences in species richness was also seen between healthy and allergic dogs, with allergic dogs having lower species richness when compared to healthy dogs.

Topographical Mapping of the Rainbow Trout (Oncorhynchus mykiss) Microbiome Reveals a Diverse Bacterial Community with Antifungal Properties in the Skin

“…Additionally, our results underscore the idea that the skin microbiota of aquatic vertebrates is very different from the skin microbiota of terrestrial or semiterrestrial vertebrates. For instance, in humans the skin microbiota is mostly composed by Firmicutes and Actinobacteria, and in dogs Proteobacteria, Actinobacteria, and Firmicutes are the main bacterial groups, but amphibians are dominated by Betaproteobacteria, particularly the family Comamonadaceae (47,51,52). In aquatic larval amphibians and, interestingly, the humpback whale, a marine mammal, Proteobacteria and Bacteroidetes dominate the skin microbiome (53,54).…”

Animal Models of Allergic Diseases

“…In the canine study, no investigation on the effects of LGG on skin or gut microbiome was done. This is an area that should be investigated further as preliminary studies on skin microbiome in allergic and normal dogs have shown that atopic dogs have less biodiversity and increased colonization by Staphylococcus compared to the healthy controls [73]. The preventative effects of this study echoed more recent metanalyses in human medicine that support a prophylactic role for probiotics, but not the therapeutic role once the disease has already been established [74].…”

The Microbiome

“…Higher microbial diversity was observed in the haired skin (axilla, groin, periocular, pinna, dorsal nose, interdigital, lumbar) compared to mucosal surfaces or mucocutaneous junctions (lips, nose, ear, and conjunctiva). 99 The nostril and conjunctiva showed the lowest, while the axilla and dorsal aspect of the nose showed highest microbial diversity. 99 On average, around 300 different bacterial genera were identified on the canine dorsal nose.…”

“…The most common phyla and families of bacteria identified in the skin of healthy and allergic dogs. Modified from Rodrigues Hoffmann et al 99 healthy dogs and dogs with diarrhea. The phyla Ascomycota (97% of fungal sequences) and Basidiomycota (1%) predominated.…”

“…99 Similar to humans, 41 the different skin sites from each dog were inhabited by a variable and unique microbiome, with significant individual variability between samples from different dogs and between different skin sites. 99 A large number of previously uncultured or rarely isolated microbes were identified, demonstrating that the skin of dogs is inhabited by diverse microbial communities. Higher microbial diversity was observed in the haired skin (axilla, groin, periocular, pinna, dorsal nose, interdigital, lumbar) compared to mucosal surfaces or mucocutaneous junctions (lips, nose, ear, and conjunctiva).…”