title: Effect of ultraviolet light C on bacterial colonization in chronic wounds.
abstract: Ultraviolet light C (light wavelength 200 nm to 290 nm) has been shown to kill cultures of antibiotic resistant strains of bacteria such as methicillin-resistant Staphylococcus aureus. To evaluate the ability of ultraviolet light C to reduce the amount and type of bacteria present in chronically infected ulcers, as well as to establish the test-retest reliability of the semi-quantitative swab technique, a prospective, one-group, pre-post treatment study was conducted among patients receiving treatment in several in- and outpatient facilities and nursing homes. Individuals with chronic ulcers exhibiting at least two signs of infection and critically colonized with bacteria (n = 22) received a single 180-second treatment using an ultraviolet light C lamp (wavelength = 254 nm) placed 1 inch from the wound bed. Semi-quantitative swabs taken immediately before and after UVC treatment were used to assess changes in the bacterial bioburden present within the wound bed. Results demonstrated excellent test-retest reliability of the semi-quantitative swab technique used to evaluate the type and amount of bacteria present in chronic wounds (Cohen's kappa = 0.92). Assessment of wound bioburden using semi-quantitative swabs revealed a statistically significant (P <0.0001) reduction in the relative amount of bacteria following a single treatment of ultraviolet light C. The greatest reduction in semi-quantitative swab scores following ultraviolet light C treatment were observed for wounds colonized with the bacteria Pseudomonas aeruginosa and wounds colonized with only one species of bacteria. Significant (P <0.05) reductions in the relative amount of bacteria also were observed in 12 ulcers in which methicillin-resistant Staphylococcus aureus was present. These results confirm previous laboratory studies and demonstrate that ultraviolet light C can kill bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus present in superficial layers of chronic wounds.
authors.affiliation: School of Physical Therapy, University of Western Ontario, London, Ontario, Canada N6G 1H1.
authors.forename: Thao P
authors.initials: TP
authors.lastname: Thai
authors.forename: David H
authors.initials: DH
authors.lastname: Keast
authors.forename: Karen E
authors.initials: KE
authors.lastname: Campbell
authors.forename: M Gail
authors.initials: MG
authors.lastname: Woodbury
authors.forename: Pamela E
authors.initials: PE
authors.lastname: Houghton
mesh_terms: D000368:Aged; D015169:Colony Count, Microbial; D005260:Female; D006801:Humans; D007871:Leg Ulcer / Q000382:microbiology / Q000628:therapy; D008297:Male; D016106:Methicillin Resistance; D003668:Pressure Ulcer / Q000382:microbiology / Q000628:therapy; D011446:Prospective Studies; D015203:Reproducibility of Results; D017192:Skin Diseases, Bacterial / Q000382:microbiology* / Q000628:therapy*; D013048:Specimen Handling / Q000379:methods*; D013203:Staphylococcal Infections / Q000628:therapy; D014467:Ultraviolet Therapy; D014946:Wound Infection / Q000382:microbiology* / Q000628:therapy*