Rao Bhamini K, Kumar Pramod, Rao Sugandhi, Gurung Bimala
Department of Physiotherapy, MCOAHS, Manipal University, Manipal, India.
Ostomy Wound Manage. 2011 Jul;57(7):46-52.
The prevalence of wound infections caused by multidrug-resistant (MDR) bacteria is increasing along with concern about widespread use of antibiotics. In vitro studies have shown that ultraviolet radiation, especially UVC, is both an effective bactericidal and antifungal. However, evidence about its bactericidal effect on wounds covered with transparent dressings remains inconclusive. Transparent dressings are used to retain moisture over the wound as part of an intermittent negative pressure dressing-the Limited Access Dressing (LAD) technique. Because this dressing is designed to remain in place for a number of days, an in vitro study was conducted to explore the bactericidal effect of direct and indirect UVR through a transparent 0.15-mm thick transparent polythene sheet on Gram-positive cocci. Six bacterial strains were inoculated to sheep blood agar (SBA) plates and exposed to direct and filtered UVC (254 nm) for 5, 10, 15, 20, 25, and 30 seconds with one media serving as a control (no UVC exposure). Plates were subsequently incubated for 24 hours and bacterial growth observed. Each set of experiment was repeated three times. Direct UVC was shown to have good bactericidal effect (100% eradication of organisms inoculated) at durations ranging from a minimum of 5 seconds (methicillin-resistant, coagulase-negative Staphylococcus and Streptococcus pyogenes) to a maximum of 15 seconds (methicillin-susceptible Staphylococcus aureus and Enterococci species). No bactericidal effect was observed when UVC was filtered through a 0.15-mm thick transparent polythene sheet. The results confirm the bactericidal effect of UVC in vitro and suggest that this effect can be achieved after a very short period of time. At the same time, film dressings appear to filter UVC. This may help protect skin from exposure to UVC but also limits its utility for use with the LAD technique. In vivo studies to evaluate the shortest effective UVC treatment duration and follow-up clinical studies to ascertain treatment efficacy and effectiveness are needed.
随着对抗生素广泛使用的担忧，耐多药（MDR）细菌引起的伤口感染患病率正在上升。体外研究表明，紫外线辐射，尤其是UVC，具有有效的杀菌和抗真菌作用。然而，关于其对覆盖透明敷料的伤口的杀菌效果的证据仍然不确定。透明敷料作为间歇性负压敷料——有限通路敷料（LAD）技术的一部分，用于保持伤口上的水分。由于这种敷料设计为在原位保留数天，因此进行了一项体外研究，以探索通过0.15毫米厚的透明聚乙烯片直接和间接紫外线辐射对革兰氏阳性球菌的杀菌效果。将六种细菌菌株接种到绵羊血琼脂（SBA）平板上，并暴露于直接和过滤后的UVC（254纳米）下5、10、15、20、25和30秒，其中一个培养基作为对照（无UVC暴露）。随后将平板孵育24小时并观察细菌生长。每组实验重复三次。直接UVC在最短5秒（耐甲氧西林、凝固酶阴性葡萄球菌和化脓性链球菌）至最长15秒（甲氧西林敏感金黄色葡萄球菌和肠球菌属）的持续时间内显示出良好的杀菌效果（接种的生物体100%根除）。当UVC通过0.15毫米厚的透明聚乙烯片过滤时，未观察到杀菌效果。结果证实了UVC在体外的杀菌效果，并表明在很短的时间内即可实现这种效果。同时，薄膜敷料似乎会过滤UVC。这可能有助于保护皮肤免受UVC暴露，但也限制了其在LAD技术中的应用。需要进行体内研究以评估最短有效的UVC治疗持续时间，并进行后续临床研究以确定治疗效果和有效性。
