Restriction of bacterial growth under commercial catheter dressings.

The effect on the normal cutaneous flora after iodine and alcohol disinfection of the skin of three commercially available moisture-permeable polyurethane dressings was compared with that of a gauze-and-tape dressing. Dressings also were evaluated clinically for membrane adhesion and skin erythema, pruritus, hyperpigmentation, vesiculitis, and tenderness. Each of 50 healthy volunteers and 49 long-term inpatients, 25 of whom were receiving antibiotic therapy, received simultaneously on their volar forearm patches of Op-Site, Tegaderm, Uniflex, and gauze dressings. Controls consisted of one exposed skin site and one covered with moisture-retaining vinylidene film (Saran Wrap). Although after 3 days of adhesion, commercial dressings prevented indigenous flora from returning to normal population densities, no significant quantitative differences were found between them and the gauze-and-tape dressing. Generally, all clinical dressings maintained normal flora at one tenth the population of the uncovered site; the Saran Wrap control supported 100-fold more bacteria than the exposed site. No differences were discovered in the levels of gram-negative bacteria, or among patient groups and between patients and healthy subjects, except for the lower incidence of erythema and itching among patients compared with healthy subjects.