Can ultraviolet light C decrease the environmental burden of antimicrobial‐resistant and ‐sensitive bacteria on textiles?

Background The environment is important in transmission of bacteria. Textiles are difficult and time consuming to clean; ultraviolet light C ( UVC ) is germicidal and may be an effective disinfection method for textile surfaces. Objective This study evaluated the efficacy of UVC , a commercial quaternary ammonium compound antimicrobial spray ( FAS ) and UVC + FAS combined for reducing bacterial colonization on experimentally contaminated textiles. Methods Microfibre, cotton and polyester were inoculated with meticillin‐sensitive and ‐resistant Staphylococcus aureus ( MSSA and MRSA ), Staphylococcus pseudintermedius ( MSSP and MRSP ), Pseudomonas aeruginosa or Escherichia coli . ATCC ® strains were used except for MRSP , for which ten canine clinical isolates were collected. Textiles were treated with three doses of UVC (13 mJ/cm 2 , 54 mJ/cm 2 or 270 mJ/cm 2 ), FAS or both ( FAS and UVC at 270 mJ/cm 2 ). UVC was delivered using a modified mercury‐based lamp. Bleach (8.25%) was used as a positive control. Negative controls received no treatment. Surface bacterial counts were determined 24 h post‐treatment. Results The lower dosages (13 mJ/cm 2 and 54 mJ/cm 2 ) of UVC had >90% colony forming unit ( CFU ) reduction, 270 mJ/cm 2 had >99% CFU reduction and combined UVC + FAS had 100% CFU reduction against all bacterial strains on all surfaces ( P < 0.05). Ten experiments showed that treatment with UVC had a greater CFU reduction when compared to FAS alone ( P < 0.05). A majority of those experiments (seven of 10) involved Gram‐negative species ( P. aeruginosa or E. coli ). Conclusion UVC quickly reduced the bacterial burden on textiles to greater than 90%; UVC may be a better disinfecting agent than FAS for Gram‐negative species.