Clinical studies In a recent clinical study, the effect of UVC for the treatment of cutaneous ulcer infections has been investigated.55 In this study, three patients were included; the first patient suffering from a diabetic ulcer, the second from a venous ulcer, and third from a recurrent ulcer all infected with methicillin-resistant S. aureus (MRSA). UVC irradiation (254 nm) was applied to each wound (for 180 s, irradiance 15.54 mW/cm2). In addition to eradication of MRSA infection upon UVC exposure, progression toward wound closure as marked by presence of epithelial buds, improved epithelialization, return of normal skin color surrounding the wound, and the emergence of healthy granulation tissue was noted. Moreover, in the latter two cases, full wound closure was achieved. In a later study performed by the same group,56 22 patients with chronic ulcers exhibiting at least two signs of infection and critically colonized with bacteria received a single 180 s treatment of UVC. Semiquantitative swabs taken immediately before and after UVC treatment were used to assess changes in the bacterial bioburden present within the wound bed. A statistically significant reduction in the relative amount of bacteria following a single treatment of UVC was observed. The greatest reduction in semiquantitative swab scores following UVC treatment were observed for wounds colonized with P. aeruginosa and wounds colonized with only one species of bacteria. Significant reductions in the relative amount of bacteria also were observed in 12 ulcers in which MRSA was present.
One advantage of using UVC over Antibiotics is that UVC can eradicate microorganisms much faster (a 2–3 log10 reduction of microorganism population in vivo could be achieved in <1 h), while Antibiotics usually take several days to take effect, especially in burns and other chronic wounds that frequently have impaired blood perfusion. UVC irradiation may also be much more cost effective than the commonly used Antibiotics .