Authors: Karissa Bauer, Kennedy Lewis, James Belnap, Andrew Torena, Braden Freestone, Luis Montenegro Calla
Mentors: Daniel Clark
Insitution: Weber State University
In the United States, 157 documented cases of primary amoebic meningoencephalitis (PAM) have been recorded between 1962 and 2022. In the 60 years since the first reported case, only four patients have survived; a 97.5% fatality rate. The causative agent responsible for the highly fatal infections, is the free-living, single-celled parasite, Naegleria fowleri— or the “brain-eating amoeba.”
The aquatic thermophiles are opportunistic pathogens that inhabit a wide range of environments; from poorly maintained pools, moist sediment, rivers, lakes, etc. Exposure to N. fowleri invasion is reliant on direct contact with a host’s upper nasal mucosa, and the active parasite. Rapid deterioration of neural tissues occurs shortly after infection.
Today, there is no universally accepted treatment plan for treating PAM infections. The CDC has recommended an empirical approach to treatment, and suggests utilizing combination drug-therapies. Suggested drugs include Amphotericin B, Azithromycin, Fluconazole, Miltefosine, and Rifampin.
To better understand and evaluate the effects of these drugs on N. fowleri, a rescue-of-infection model was applied to test the efficacy of single and combination-drug treatments, at various time points. The model utilized an immortalized HeLa cell line that was infected with the amoebae until roughly 50% cytotoxicity was observed. The rescue stage commenced with drug additions, and HeLa cell metabolism, and apoptosis levels were monitored using fluorescence viability assays and caspase-3 enzyme detection systems.
Drug combinations that included Rifampin and Amphotericin B, provided the greatest protection for human Hela cells against N. fowleri infections. Data collected from this model provides deeper understanding of Naegleria fowleri pathogenicity. This knowledge will aid the development of more reliable and efficient treatments for this devastating infection.