Skin microbes on frogs prevent morbidity and mortality caused by a lethal skin fungus

• Published in: The ISME Journal Vol. 3; no. 7; pp. 818 - 824
• Main Authors: Harris, Reid N, Brucker, Robert M, Walke, Jenifer B, Becker, Matthew H, Schwantes, Christian R, Flaherty, Devon C, Lam, Brianna A, Woodhams, Douglas C, Briggs, Cheryl J, Vredenburg, Vance T, Minbiole, Kevin P C
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-07-2009; Nature Publishing Group
• Subjects: Amphibians; Animals; Antibiosis; Antifungal Agents - metabolism; Antifungal Agents - pharmacology; Batrachochytrium dendrobatidis; Biomedical and Life Sciences; Chytridiomycota - growth & development; Community structure; Dermatomycoses - prevention & control; Ecology; Evolutionary Biology; Humans; Immune system; Indoles - metabolism; Indoles - pharmacology; Infectious diseases; Janthinobacterium lividum; Life Sciences; Metabolites; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Morbidity; Mortality; original-article; Oxalobacteraceae - physiology; Pathogens; Population decline; Rana muscosa; Ranidae - microbiology; Skin - microbiology; Skin diseases; Survival Analysis; Wildlife; bioaugmentation; violacein; chytridiomycosis
• ISSN: 1751-7362; 1751-7370
• DOI: 10.1038/ismej.2009.27

Emerging infectious diseases threaten human and wildlife populations. Altered ecological interactions between mutualistic microbes and hosts can result in disease, but an understanding of interactions between host, microbes and disease-causing organisms may lead to management strategies to affect disease outcomes. Many amphibian species in relatively pristine habitats are experiencing dramatic population declines and extinctions due to the skin disease chytridiomycosis, which is caused by the chytrid fungus
Batrachochytrium dendrobatidis
. Using a randomized, replicated experiment, we show that adding an antifungal bacterial species,
Janthinobacterium lividum
, found on several species of amphibians to the skins of the frog
Rana muscosa
prevented morbidity and mortality caused by the pathogen. The bacterial species produces the anti-chytrid metabolite violacein, which was found in much higher concentrations on frog skins in the treatments where
J. lividum
was added. Our results show that cutaneous microbes are a part of amphibians' innate immune system, the microbial community structure on frog skins is a determinant of disease outcome and altering microbial interactions on frog skins can prevent a lethal disease outcome. A bioaugmentation strategy may be an effective management tool to control chytridiomycosis in amphibian survival assurance colonies and in nature.