The effects of antibacterial antibiotics on survival and biofilm formation in the amphibian pathogen Batrachochytrium dendrobatidis

The pathogen Batrachochytrium dendrobatidis (Bd) is a known fungal pathogen associated with an increase in amphibian mortalities worldwide. Previous research has shown a decrease or complete clearance of infection when infected animals are treated with a topical preparation of the antibiotic chloramphenicol. Chloramphenicol has been found to be effective at killing the pathogen in vitro. Previous studies in our lab have shown that Bd is capable of forming a biofilm in vitro. We hypothesized that Bd grown in a medium containing antibiotics should decrease its biofilm formation. To investigate this, we tested the growth and biofilm formation of Bd in the presence of various antibiotics, including novobiocin, kanamycin, penicillin, streptomycin, chloramphenicol and ampicillin. Inhibition of biofilm formation and these found organisms in Bd could lead to the development of strategies that could be used to control Bd infections in amphibian populations.

In a related study, we have observed an extracellular structure associated with Bd cultures. In an effort to determine the origin of these entities, we used antibacterial antibiotics to study their impact of the “existence” of these entities. Prokaryotic “symbionts” of unicellular eukaryotes have been observed previously.  Inhibiting growth and isolating these structures could help us further understand if they are associated with Bd, and if so, how.