Pathogenesis and prevention of intravenous catheter infections.

Intravenous (iv) catheters are used frequently in hospitalized patients today. The most common complication of iv therapy is infection. Several studies (1-3) have reported the incidence of bacterial colonization of iv devices to range from 30 to 78%. In these reports, the local application of neomycin-polymyxin-bacitracin ointment to the insertion site did not produce uniform results in preventing infection. Moran (3) showed a significant decrease in the incidence of organisms recovered from surgically placed iv cutdowns to which this ointment had been applied. In the other studies by Norden (4) and Zinner et al. (5), there was no overall reduction in colonization of iv catheters using the same antibiotic ointment. Paradoxically, the high frequency of bacterial isolation from iv devices cited in the literature, yields low rates of bacteremia (2-4%) and correlate poorly with phlebitis. Despite the high incidence of recovery of organisms, the source and significance of bacteria isolated from the iv catheter tip have not been established. The purpose of this study is to establish via a double-blind trial, the efficacy of the local application of gentamicin cream in preventing colonization and infection of iv catheters. Unlike previous experimental protocols, organisms recovered from iv devices were compared to cultures of skin flora before insertion and at the time of removal of the catheter. This procedure was employed for two reasons: (1) In order to determine the frequency of local skin flora as a source of bacteria leading to subsequent colonization and infection of the iv catheter, and (2) the potential of preventing infection from this source with local gentamicin. Finally,