White-nose syndrome (WNS), caused by the cold-loving fungus Pseudogymnoascus destructans, has devastated bat populations across eastern North America. It infects hibernating bats, depleting their fat stores and waking them when food is scarce. The white fungus grows on the bats' wings, ears, and nose (hence "white-nose") and has killed an estimated 6 million bats over the past decade. No small matter, considering these bats save U.S. farmers nearly $23 billion per year by munching on insects that would otherwise damage crops (Science Magazine).
Two groups of researchers have turned to bacteria for help. Christopher Cornelison, a postdoctoral research associate in the Sidney Crow lab at Georgia State University, treated WNS-infected bats with the gram-positive bacterium Rhodococcus rhodochrous. This soil-dwelling bacterium produces volatile organic compounds that inhibit fungal growth (BMC Microbiology 2014, 14:246). In collaboration with the Kentucky Department of Fish and Wildlife Resources, Cornelison placed Petri dishes containing R. rhodochrous in caves containing WNS-infected bats. On May 19th, the team released the fungus-free bats back to the wild (check out the video). The next challenge is to develop an effective treatment protocol. The Crow lab is currently testing a patent-pending device to disperse the antifungal organic compounds. (Georgia State University)
Similarly, Joseph Hoyt, a graduate student in the Marm Kilpatrick lab at the University of California Santa Cruz, showed that Pseudomonas isolates from bat wings inhibited the growth of P. destructans. Hoyt and colleagues showed that two strains of Pseudomonas fluorescens significantly inhibited fungal growth on agar plates. In fact, these strains are commonly found on bats that show lower WNS mortality rates. The group hopes to develop a "probiotic" treatment for bats using these Pseudomonas isolates. (J. R. Hoyt et al. PLoS ONE 10, e0121329; 2015)
There is one caveat, however. These treatments do not provide the bats with any immunity to future infection. In fact, it is unclear whether a WNS vaccine would even be useful. According to Bucknell University ecoimmunologist Ken Field, bats do produce antibodies to P. destructans, but they do not appear to enhance survival. (Nature News)