Inactivation kinetics of 280 nm UV-LEDs against Mycobacterium abscessus in water

Abstract

AbstractNontuberculous mycobacteria (NTM) are opportunistic premise plumbing pathogens (OPPPs) that cause a burdensome waterborne respiratory disease. Due to their resistance to chemical disinfectants and regrowth in biofilms in drinking water distribution systems, treatment can be better performed using small ultraviolet disinfection units at the point-of-use (POU), such as at a tap or showerhead. Ultraviolet light-emitting diodes (UV-LEDs) are well suited for such applications, but fluence-response data are not available for one of the most important NTM,Mycobacterium abscessus. In this study, a bench-scale 280 nm UV-LED apparatus was used to irradiateM. abscessusin a water matrix. The fluence-response profile was sigmoidal, exhibiting both shoulder and tailing phenomena. Simple linear regression and the Geeraerd’s inactivation kinetics model yieldedkvalues of 0.36 and 0.37 cm2/mJ, respectively, revealing thatM. abscessusis more resistant to UV thanPseudomonas aeruginosaandLegionella pneumophila, which suggests that NTM are among the most UV-resistant OPPPs. Results of this study suggest that 280 nm UV-LED irradiation can be an effective and practical option to inactivateM. abscessusat the POU. Disinfection units that can deliver a fluence of 10 mJ/cm2are expected to achieve nearly 2 log (99%) inactivation ofM. abscessus.