Differences in UV-C LED Inactivation of Legionella pneumophila Serogroups in Drinking Water
Citation:
Buse, H., J. Hall, G. Hunter, AND J. Goodrich. Differences in UV-C LED Inactivation of Legionella pneumophila Serogroups in Drinking Water. Microorganisms. MDPI, Basel, Switzerland, 10(2):352, (2022). https://doi.org/10.3390/microorganisms10020352
Impact/Purpose:
The observed variations between studies underscores the need for systematic testing of different L. pneumophila strains to understand the efficacy and mechanisms of UVC-LED treatment. This is especially warranted since UV LED technology is being increasingly applied in drinking water treatment to address the public health concern of L. pneumophila and other waterborne pathogens in these systems.
Description:
Legionella pneumophila (Lp) is an opportunistic pathogen that causes respiratory infections primarily through inhalation of contaminated aerosols. Lp can colonize premise plumbing systems due to favorable growth conditions (e.g., lower disinfectant residual, stagnation, warm temperatures). UV-C light emitting diodes (UV-C LEDs) are an emerging water treatment technology and have been shown to effectively inactivate waterborne pathogens. In this study, inactivation of four Lp strains (three clinical sg1, 4, and 6; and one sg1 drinking water [DW] isolate) were evaluated using a UV-C LED collimated beam at three wavelengths (250, 265, and 280nm) and six fluence rates (0.5-34 mJ/cm2). Efficacy testing was also performed using a UV-C LED point-of-entry (POE), flow-through device. Based on the log inactivation curves, at 255nm, the sg4 and sg6 clinical isolates were more susceptible to inactivation compared to the two sg1 isolates. However, at 265 and 280nm, the sg1 and sg4 clinical isolates were more resistant to inactivation compared to the sg6 clinical and sg1 DW isolates. Differential log reductions were also observed using the POE device. Results indicate that although UV-C LED disinfection is effective, variations in Lp inactivation, wavelengths, and technology applications should be considered, especially when targeting specific isolates within premise plumbing systems.
URLs/Downloads:
DOI: Differences in UV-C LED Inactivation of Legionella pneumophila Serogroups in Drinking Water