To the batcave! Scientists hunting white-nose syndrome clues discover new bacteria
Posted on January 15, 2015 by Jon Fuhrmann
Researchers from the Czech Republic recently had a lucky break when they discovered not one but two new species of bacteria in bats that were emerging from hibernation in the Jeseníky Mountains in the north of the country. The discoveries were fortuitous coincidence, as the team were not specifically looking for new species of bacteria.
As Dr Paula Garcia-Fraile, lead author of the paper describing the new species in the International Journal for Systematic and Evolutionary Microbiology, told Microbe Post, the main aim was to isolate strains of the fungus Pseudogymnoascus destructans.
P. destructans causes white-nose syndrome, a disease that has decimated the populations of numerous bat species across North America in recent years. While the fungus is associated only with diseased bats in America, both healthy and diseased bats in Europe were found to carry the fungus. The likely explanation is that European bats have developed some immunity to the fungus over time, and that it is now wreaking havoc with American bats which have not been exposed to it before. The researchers are keen to understand how P. destructans interacts with other microbes in bats and how this may affect the occurrence and fatality of white-nose syndrome.
The new species were named Serratia myotis and Serratia vespertilionis, both names referring to the fact that they were isolated from bats. So far, the researchers have not found any links between the bacteria and white-nose syndrome in bats, or any indication that they may be dangerous to humans. However, one member of the Serratia genus, S. marcescens, has a dark history, warranting careful study of the new bacteria. In 1950, the US Army released balloons filled with the bacterium over San Francisco to simulate a biological warfare attack on the city. The pathogenic nature of the species was unknown at the time and was only discovered decades later, explaining the spike in hospital admissions with infections in 1950.
Other members of the genus Serratia can be found living in oceans, soil and plants, but also in various animals. Some species have been known to cause diseases such as mastitis in cows and conjunctivitis in horses. Garcia-Fraile and her team are now studying the newly discovered bacteria more closely to understand their interactions with other microbial species and to ascertain whether they pose any danger to humans or animals.
S. myotis and S. vespertilionis were isolated from samples taken from different parts of the bats’ bodies as they emerged from hibernation into the open. Bats can spend up to 200 days a year in a sleep-like torpor in caves, avoiding the cold winter conditions outside. Their body temperature and metabolism are reduced to a bare minimum to conserve energy. In order to take samples from the bats without harming them, the team used mist nets – near-invisible wire mesh nets in which the animals got caught as they exited their caves. Safely disentangling the bats requires significant training, but mist nets have the lowest recorded animal injury rates out of any method for studying vertebrates.
Once the samples had been taken and the bats released, the individual bacterial strains found in the samples were cultivated in sheep’s blood agar. Blood agar is particularly suitable for growing bacteria isolated from living animals as it is very rich in nutrients, allowing the highest possible number of strains to grow. Besides S. myotis and S. vespertilionis, Garcia-Fraile and her colleagues also isolated a number of other bacteria that are not found in American bats suffering from white-nose syndrome.
Going forward, the discovery of two new species has opened up an exciting new avenue of research for Garcia-Fraile and her team. They hope to study these strains, along with others that do not occur in North America, to see whether any of these bacteria could be used to help stop white-nose syndrome in the new world, and whether they might be of use in human or veterinary medicine.
Garcia-Fraile, P., Chudi kova, M., Benada, O., Pikula, J., & Kola ik, M. (2014). Serratia myotis sp. nov. and Serratia vespertilionis sp. nov. isolated from bats hibernating in caves in the Czech Republic International Journal of Systematic and Evolutionary Microbiology DOI: 10.1099/ijs.0.066407-0