Common Cutaneous Bacteria from the Eastern Red-Backed Salamander Can Inhibit Pathogenic Fungi

Abstract

The objective of this study was to characterize the cutaneous antifungal bacterial flora of a plethodontid salamander, Plethodon cinereus, and to relate our results to aspects of amphibian ecology. Scanning electron micrographs of salamander skin indicated a wide distribution of bacteria across the skin. Polymerase Chain Reaction/Denaturant Gradient Gel Electrophoresis (PCR/DGGE) analyses of 16S rRNA gene fragments revealed that a transient community of bacteria was rinsed off and that a resident epibiotic community remained on the skin. Resident bacteria were isolated from the skin of P. cinereus on a low nutrient medium and challenged against a pathogenic ascomycete fungus collected from dead salamander eggs. The strong antifungal bacteria, identified by sequencing of the 16S rRNA gene (∼1400 bp), were related to the genera Lysobacter, Pseudomonas, Chryseobacterium, and Bacillus. Patterns of the cutaneous bacterial flora varied among individual salamanders, as revealed by DGGE, although analysi...