The Environmental and Health Competency of UV Irradiation on Pseudomonas
Daniel Alejandro Urista, Ashley Lim
Department of Biology
Faculty Supervisor: Lily Chen
Since the COVID-19 pandemic, UV irradiation became a common method for surface sterilization in high-traffic areas. Pseudomonas bacteria are ubiquitous in the environment, leading to health inequity concerns. The use of chemicals to eradicate bacteria disproportionately affects communities of color. Patients in healthcare facilities and individuals in agricultural and janitorial services are especially vulnerable. This study examines UV irradiation's effect on two Pseudomonas species (P. aeruginosa, a known clinical isolate, and M10, a mushroom isolate) and the correlation between exposure time and distance. Bacteria were cultured in LB media to the active growth phase, and a standardized suspension was inoculated onto LB agar plates. The plates were exposed to UV light at distances of 4 feet (ft) or 8 feet for 0 to 1200 seconds (s). The cultures were incubated and growth colonies were counted. The percentage of reduction was calculated compared to time 0s. Results showed exposure at 4ft for 120s and 8ft for 900s reduced over 90% of P. aeruginosa, compared to 4ft for 360s and 8ft for 1200s in eliminating 90% of M10 growth; these results show UV irradiation is more effective at eliminating P. aeruginosa and could address environmental injustices affecting immunocompromised and minority populations.