A pilot study of re-purposing drugs to treat koalas with chlamydia.

The koala (Phascolarctos cinereus) is an endangered species in parts of Australia, in part due to chlamydial infections. Treatment is difficult due to the hepatic metabolism of the koala, and the critical reliance on a gut microbiota for survival. This study aimed to identify new compounds for treatment of Chlamydia infections by screening a drug re-purposing library. Screening was conducted using an in vitro cell culture model prior to in vivo mouse infection model testing of two candidates identified from the in vitro screen. One lead, bisoprolol fumarate, showed an impact on chlamydial infection and burden in vitro and in vivo. Whilst the mechanism of action may not support progressing this lead further, the approach to screening the library and list of candidates may enable identification of other new koala treatments. This study demonstrates the potential to apply drug re-purposing to koala treatment and presents a list of candidates that could be explored further.