A preliminary report on the contact-independent antagonism of Pseudogymnoascus destructans by Rhodococcus rhodochrousstrain DAP96253

Abstract

BackgroundThe recently-identified causative agent of White-Nose Syndrome (WNS), Pseudogymnoascus destructans, has been responsible for the mortality of an estimated 5.5 million North American bats since its emergence in 2006. A primary focus of the National Response Plan, established by multiple state, federal and tribal agencies in 2011, was the identification of biological control options for WNS. In an effort to identify potential biological control options for WNS, multiply induced cells of Rhodococcus rhodochrous strain DAP96253 was screened for anti-P. destructans activity.ResultsConidia and mycelial plugs of P. destructans were exposed to induced R. rhodochrous in a closed air-space at 15°C, 7°C and 4°C and were evaluated for contact-independent inhibition of conidia germination and mycelial extension with positive results. Additionally, in situ application methods for induced R. rhodochrous, such as fixed-cell catalyst and fermentation cell-paste in non-growth conditions, were screened with positive results. R. rhodochrous was assayed for ex vivo activity via exposure to bat tissue explants inoculated with P. destructans conidia. Induced R. rhodochrous completely inhibited growth from conidia at 15°C and had a strong fungistatic effect at 4°C. Induced R. rhodochrous inhibited P. destructans growth from conidia when cultured in a shared air-space with bat tissue explants inoculated with P. destructans conidia.ConclusionThe identification of inducible biological agents with contact-independent anti- P. destructans activity is a major milestone in the development of viable biological control options for in situ application and provides the first example of contact-independent antagonism of this devastating wildlife pathogen.

Western Bats as a Reservoir of Novel Streptomyces Species with Antifungal Activity

“…In similar studies, a Streptomyces isolate from the Soudan Iron Mine in Minnesota, USA, initially recognized as S. albus, has exhibited potent antagonistic activity against P. destructans (36). Experiments by Cornelison et al also demonstrated that R. rhodochrous could completely inhibit P. destructans on bat tissue by slowing germination and reducing mycelial growth when cultured with shared air space at 15°C (30). We identified a similar isolate classified as R. rhodochrous (AC241) from a healthy M. velifer bat that completely inhibited P. destructans growth when using a bilayer plate assay.…”

“…In previous studies, bacteria have shown the capacity to inhibit P. destructans in vitro (30). For example, Hoyt et al showed that bat bacterial isolates in the genus Pseudomonas obtained from Eptesicus fuscus and Myotis lucifugus inhibit P. destructans for at least 37 days (31).…”

Efficacy of a probiotic bacterium to treat bats affected by the disease white‐nose syndrome

“…Further progress in the protection of imperilled bat populations in North America will require an adaptive management approach that should include field trials for probiotics and other biological agents (Cornelison et al . ) and exploration of other interventions, such as habitat decontamination (Bosch et al . ) and microclimate manipulations (Boyles & Willis ; Langwig et al .…”

Probiotics as a tool for disease mitigation in wildlife: insights from food production and medicine

“…Bacterial species isolated from bats can inhibit Pd in vitro . Indeed, the bacterial species Rhodococcus rhodochrous emits volatile organic compounds that can kill Pd . In an experiment with little brown bats, inoculation with the anti‐Pd bacterial species Pseudomonas fluorescens led to a 40% increase in survival over controls.…”