title: Inactivation/reactivation of antibiotic-resistant bacteria by a novel UVA/LED/TiO2 system.
abstract: In this study, an effective photocatalytic disinfection system was established using the newly emerged high power UVA/LED lamp. Crystallizing dish coated with TiO2 was prepared by 32-times impregnation-drying processes, and served as the supporting container for water samples. This study focused on the application of this UVA/LED system for the photocatalytic disinfection of selected antibiotic-resistant bacteria, Escherichia coli ATCC 700891. The disinfection performances were studied under various light intensities and illumination modes. Results show that higher light intensity could reach more significant inactivation of E. coli ATCC 700891. With the same UV dose, log-removal of antibiotic-resistant bacteria decreased with circle time in the studied range, while increased with duty circle. A "residual disinfecting effect" was found in the following dark period for bacteria collected at different phases of photocatalytic process. Residual disinfecting effect was found not significant for bacteria with 30 min periodic illumination. While residual disinfecting effect could kill almost all bacteria after 90 min UV periodic illumination within the following 240 min dark period.
authors.affiliation: Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: Pei
authors.initials: P
authors.lastname: Xiong
authors.forename: Jiangyong
authors.initials: J
authors.lastname: Hu
mesh_terms: D002384:Catalysis / Q000187:drug effects / Q000528:radiation effects; D003460:Crystallization; D004203:Disinfection; D004352:Drug Resistance, Microbial / Q000187:drug effects* / Q000528:radiation effects; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification / Q000528:radiation effects* / Q000648:ultrastructure; D008280:Magnetics; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects*; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: C009495:titanium dioxide; D014025:Titanium
keywords: Antibiotic-resistant bacteria; Inactivation; Periodic illumination; Reactivation; UVA/LED