Skin bacteria and Op Site chest dressings

Growth of skin bacteria on the infraclavicular region was studied in two series of male volunteers. In the first, Op Site, a polyurethane adhesive film dressing, was compared with an occlusive polyvinyl chloride (PVC) dressing, on povidone iodine (PVI) prepared skin in 10 volunteers. Bacteria were sampled, using perspex cylinders and buffered Triton X-100 detergent, at 2, 4, 7 and 14 days, cultured aerobically and anaerobically, and colonies counted at 24 and 48 h respectively. Colony counts under Op Site were less than for undressed (control) skin and under PVC, at all days sampled, the difference being statistically significant at 2 and 14 days for controls and 4 days for PVC. In the second, four regimens of skin preparation, with Op Site dressings were compared in 12 volunteers, skin being sampled 4, 7 and 14 days. Chlorhexidine (CHD) and PVI were compared with and without defatting. Defatting significantly reduced colony counts at 4 and 7 days, whereas no differences were demonstrated between CHD and PVI. The combination of defatting and CHD resulted in colony counts consistently less than 10(3) organisms at 4 and 7 days. Op Site does not potentiate the growth of skin bacteria and is preferable to an occlusive PVC adhesive dressing. Op Site may be left intact on the chest for up to 7 days, colony counts remaining within acceptable limits.