Antibiotic irrigation and catheter-associated urinary-tract infections.

To investigate the efficacy of antibiotic irrigation in preventing catheter-associated urinarytract infection, we carried out a randomized controlled trial of a neomycin-polymyxin irrigant administered through closed urinary catheters. Eighteen of 98 (18 per cent) of the patients not given irrigation became infected, as compared with 14 of 89 (16 per cent) of those given irrigation, yielding a mean daily incidence of 5 per cent in each group. The distribution of organisms and their antibiotic sensitivities differed in the two groups, the organisms from the patients with irrigation being more resistant. Disconnections of the catheter junctions were associated with high rates of infection. The rate of disconnections of the junctions in the group given irrigation was almost twice that of the control group because of the presence of the extra junction on overall infection rate represents the result of two opposing phenomena: the increased entry of organisms and the suppression of a portion of them.