Antibiotic-resistant bacteria inactivation in water with UVLEDs


Avaro Arnalot, David 


In the present study, the effect of two different UV-LED wavelengths (255 and 265 nm) and their combination (255/265 nm) is investigated on the inactivation of antibioticsensitive and antibiotic-resistant E.coli. The tested antibiotics are Ampicillin, Ciprofloxacin, and Sulfamethoxazole at a concentration of 64, 4 and 512 mg/L, respectively. For the contaminated water, a synthetic greywater was created to be inoculated with the two strains of E. coli and its posterior disinfection by UV radiation with a lab-scale UV-LED equipment. The used equipment is capable to combine different wavelengths up to three at the same time. About 3-log reduction was obtained at lower concentrations (106 and 107 CFU/mL) at 5,5 mJ/cm2 fluence by a wavelength of 265 nm.
A higher reduction of 5-log was obtained for concentrations of 108 CFU/mL at 12,24 mJ/cm2 fluence with the combined wavelength of 255/265 nm. The sensitivity to UV radiation of antibiotic-resistant E. coli resulted to be similar to that of antibiotic-sensitive E. coli, but some differences could be seen experimentally.



Auset Vallejo, María


IQS SE -  Undergraduate Program in Biotechnology