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Providing evidence to improve practice

Individual study: Skin bacteria that inhibit the chytrid fungus can be added to skins of red-backed salamanders resulting in reduced severity of the disease

Published source details

Harris R.N., Lauer A., Simon M.A., Banning J.L. & Alford R.A. (2009) Addition of antifungal skin bacteria to salamanders ameliorates the effects of chytridiomycosis. Diseases of Aquatic Organisms, 83, 11–16

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Use antifungal skin bacteria or peptides to reduce chytridiomycosis infection Amphibian Conservation

A randomized, replicated, controlled study in a laboratory in Virginia, USA (Harris et al. 2009) found that the severity, but not the infection rate, of chytridiomycosis was reduced by adding chytrid-inhibiting skin bacteria to the skin of red-backed salamanders Plethodon cinereus. Infection rate did not differ significantly between those with added bacteria (Pseudomonas reactans; 80%) and those with chytrid alone (60%). Numbers of zoospore equivalents on infected individuals were also similar (with bacteria: 6; chytrid alone: 10). However, by day 46, salamanders with the bacteria had lost significantly less body mass (15%) than those with chytrid alone (30%) and a similar amount to controls (bacteria or medium alone: 8%). Following inoculation with skin bacteria, 89% of 18 individuals tested positive for the bacteria. Individuals were randomly assigned to one of four exposure treatments: anti-chytrid skin bacteria, chytrid zoospores, bacteria followed by chytrid zoospores three days later or solution alone. Sample sizes were 5, 20, 20 and 5 respectively. Individuals were tested for chytrid on day 1 and 14 and for skin bacteria on day 1 and 10. Salamanders were bathed with 5 ml of solution containing bacteria (3 x 109 cells/ml) for two hours and/or a solution with chytrid (3 x 106 zoospores/5 ml) for 24 hours.