UV-C inactivation of Legionella rubrilucens

Abstract

Background: Despite the great health significance of , there is only little information on their UV sensitivity. Besides only has been investigated so far. Methods: In this study has been spread on buffered charcoal yeast extract agar and irradiated with the 254 nm UV-C emission of a mercury vapor lamp. The disinfection success is measured by colony counting after incubation and comparison of the number of colonies on irradiated and unirradiated reference agar plates.Results: The average log-reduction dose is 1.08 mJ/cm for free which is at the lower end of the so far published Legionella log-reduction values, but all three species show similar sensitivities. Conclusion: The log-reduction dose of legionellae in amoebae has not been investigated, but with the observed high UV-C sensitivity for free , the idea of a future point-of-use disinfection by small UV-C LEDs in water-taps or shower heads appears to be realistic, even if legionellae are more resistant in amoebae.

Keywords

• Legionella
• UV-C radiation
• mercury vapor lamp
• log-reduction dose
• point-of-use disinfection