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Bacteria and Fungi

The Science of Bacteria and Fungi

For years veterinarians, clinicians, and scientists have been studying the microorganisms that live on the skin and in the ears of dogs. These microorganisms, including bacteria and fungi, are usually referred to as the ‘microbiota’ [1]. This microbiota can influence the dog’s health by providing a barrier against pathogens, preventing hypersensitization to environmental allergens, and interacting with the host cells to impact cellular function and immunity [1,2]. We know there is a large variety of microorganisms living on your dog that differ by location on the body and by individual [2,3].

Only with the help of Next-Generation Sequencing technology can we really reveal just how diverse this microbiota is, and how it can contribute to canine skin and ear well-being. For example, an imbalance in the bacterial composition and a reduction of bacterial diversity of the skin is often associated with atopic dermatitis [3-5]. The skin of these dogs tends to show higher abundance of Staphylococcus sp. and Corynebacterium sp. [4]. Staphylococcus also tends to be higher on skin of dogs with allergen-induced atopic dermatitis [6]. It is quite important to identify and understand these dog–bacteria interactions because these skin microbes may not only invade and infect the skin but can also contribute to the inflammatory response [7].

Figure 1: Each circle represents the total bacterial composition in different sites on the skin of healthy dogs. Every color represents a different bacterium. (Figure adapted from [3])

When we sequence the DNA of all the bacteria and fungi that are present in a patient’s sample, we can directly identify potential pathogens, assess the microbial diversity, and compare the patient’s sample with those of healthy dogs as controls. An example is shown in figure 2 (to the right) where there is a striking difference between the healthy sample on the top, and the diseased skin sample on the bottom.

Figure 2: Bacterial composition comparing the relative bacterial abundance of healthy dogs to a dog with a skin disease.

Scientific research reveals shifting the abundance of specific bacterial and fungal species can contribute to diseases. Assessing the skin and ear microbiota as a clinical tool can assist by providing the necessary information for detecting susceptibility, providing diagnosis, and aiding the timely treatment of dermatological canine diseases. MiDOG® is now making this technology available to veterinarians.



1. Cusco, A. et al. Microbiome (2017)

2. Meason-Smith, C. et al. FEMS Microbiol. Ecol (2015)

3. Hoffmann, A. R. et al. PLoS One (2014)

4. Bradley, C. W. et al. J. Invest. Dermatol (2016)

5. Santoro, D. et al. Vet. Dermatol (2015)

6. Pierezan, F. et al. Vet. Dermato. (2016)

7. Santoro, D. et al. A. J. Invest. Dermatol (2016)

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