IDENTIFICATION OF THE NATURAL BACTERIAL MICROFLORA ON THE SKIN OF EASTERN NEWTS, BULLFROG TADPOLES AND REDBACK SALAMANDERS

Amphibian populations in several regions of the world appear to be declining due to infectious diseases. While many studies have attempted to identify the pathogens associated with specific declines, very few studies have attempted to identify the natural microflora that is present on amphibian skin. Knowledge of the natural flora that healthy individuals carry may, in some cases, provide valuable information for understanding disease outcomes. In this study, we isolated the natural bacterial flora found on the skin of apparently healthy adult eastern newts (Notophthalamus viridescens), larval bullfrogs (Rana catesbieana) and redback salamanders (Plethodon cinereus) living in natural field sites in Virginia. We positively identified five bacterial species from newts, three bacterial species from bullfrogs and four bacterial species and one yeast from redback salamanders. In a parallel study, we examined the physiological profiles of bacterial communities at six sites with newt and bullfrog tadpole populations. A cluster analysis resulted in two main groupings: one for all the water samples and one for all the skin swab samples from the amphibians. This result suggests that only a sub-set of bacteria in the environment are able to successfully colonize amphibian skin.