Scott Nagao, Weber State University
Microbiology
Batrachochytrium dendrobatidis belongs to the fungal phylum Chytridiomycota (chytrids), and in 1999, was both identified as a new species and associated with causing chytridiomycosis in amphibians. Since its identification, this fungus has been implicated in rapid population declines in multiple amphibian species in North and Central America, Europe, and Australia. In adult amphibians, the fungus colonizes only the keratinized skin cells on the ventral and dorsal surfaces as well as on the webbing between the toes. Infection is associated with hyperkeratosis resulting in disruption of the skin’s osmoregulatory function, dehydration, electrolyte imbalance and death. There is data that indicates some bacteria that live on the epidermis of amphibians produce chemicals that inhibit the growth of B. dendrobatidis. However, this data is associated only with salamanders. There is no similar inhibitor data published for frog and toad species, and no data published on the identification of normal skin biota of frogs and toads. We have isolated over 175 bacterial isolates from 67 toads and frogs, extracted DNA, and used PCR to amplify the 16S ribosomal DNA gene. Amplicons have been sequenced to determine speciation based on genetics. This is the first report of normal bacterial skin biota in frogs. Further, a skin swab was also taken from these frogs and used to analyze which are infected with B. dendrobatidis via quantitative PCR screening. While the prevalence of fungal infection appears to be low, we have been able to correlate fungal-positive hosts with number and/or species of normal bacterial skin biota.