Selective Photocatalytic Disinfection of Legionella pneumophila

Abstract

By Justin Howard, Biomedical Engineering; Elijah Ditchendorf, Biomedical Engineering

Advisor: David Wendell

Presentation ID: PM_D11

Abstract: Despite well-established disinfection treatment protocols at water treatment facilities in the United States, outbreaks of waterborne disease in treated water still occur, as seen by several recent cases of Legionnaires' disease in New York City and New Hampshire Hampton Beach. The causative bacteria, Legionella pneumophila, has become increasingly thermophilic, as evidenced by the Hampton Beach Hotel hot tub outbreak, while remaining resistant to many common disinfectants like chlorine, allowing it to persist in residential and medical water systems. Here we report efficient, multi-log photodisinfection of L. pneumophila using a protein photocatalytic disinfection system produced in E. Coli. This system is comprised of the Strep-MiniSog complex previously engineered by this lab (Wurtzler, E. M., & Wendell, D. (2016). Selective Photocatalytic Disinfection by Coupling StrepMiniSog to the Antibody Catalyzed Water Oxidation Pathway. PloS one, 11(9), e0162577.) and a biotinylated antibody purchased through NOVUS specific to L. pneumophila. Alternatively, the FAB antibody fragment specific to L. pneumophila along with a singlet oxygen-generating domain, produced in E. coli bacteria for expression, will be used for disinfection trials. Our disinfection technology generates reactive oxygen from blue light and has several advantages over current metal and polymer-based strategies including: selective, targeted, species-specific disinfection; biodegradability and compatibility with consumption; lack of harmful disinfection byproducts, and renewable production. The disinfection trials will involve introduction of the photocatalyst into a solution of live L. pneumophila cells in buffer, exposure to 450 nm light for different time periods, and subsequent measurements of cell death by plating serial dilutions.