I read with interest the study by Tennenberg et al1 demonstrating that antiseptic-impregnated catheters reduce the risk of catheter-related infection. However, these results may be flawed because the potential impact of residual anti-infective compounds from the coated catheter on the subsequent microbiologic culture was not discussed.
For example, Schmitt et al2demonstrated in an in vitro study that antiseptic compounds elute from catheters during culturing processes. Their findings show that it is critical for all culture techniques to include inhibitors of the antiseptic catheter compounds. Results of a previous study employing inhibitors3 to examine the bacterial colonization on 116 antiseptic-bonded and 117 control catheters showed that all antiseptic catheters retained antibacterial activity in patients for at least 5 days, and some of them for up to 20 days. These findings and the recent report by Maki et al4 demonstrate a long-lasting effect of antiseptic compounds on impregnated catheters. Because these antiseptic compounds may be transferred into the culture media, falsely low bacterial counts may have occurred if Tennenberg et al1 did not add inhibitors to their culture media.
Bach A. A Randomized Trial of an Antibiotic- and Antiseptic-Coated Central Venous Catheter in the Prevention of Catheter-Related Infections. Arch Surg. 1998;133(9):1022. doi: