The use of bladder catheters is common in hospitalized patients. Their use increases the incidence of bacterial urinary tract infections. Various methods have been developed in an attempt to reduce infection rates in patients requiring bladder catheters. Darouiche and colleagues studied the effectiveness of bladder catheters impregnated with minocycline and rifampin in reducing catheter-associated bacteriuria.

The prospective study enrolled 124 patients who were undergoing radical prostatectomy at one of five medical centers. Patients were randomized to receive regular silicone bladder catheters or catheters impregnated with minocycline and rifampin. The catheters remained in place for a median of two weeks. Urine cultures were obtained approximately three, seven and 14 days after catheter insertion. Bacteriuria was defined as growth of organisms in the urine at concentrations of 104 colony-forming units per milliliter or more.

The antimicrobial-impregnated catheter group had significantly lower rates of gram-positive bacteriuria than the standard catheter group, but both groups had similar gram-negative bacteriuria rates. Patients with the impregnated bladder catheters who developed bacteriuria took longer to develop the condition than those who received a standard bladder catheter. The antimicrobial-impregnated catheter produced inhibition against Enterococcus faecalis and Escherichia coli at baseline and on removal.

The authors conclude that bladder catheters impregnated with minocycline and rifampin significantly reduce the rate of gram-positive catheter-associated bacteriuria for up to two weeks after catheter insertion. In patients who may need the use of indwelling bladder catheters for up to two weeks, impregnated catheters may reduce their risk of catheter-associated bacteriuria.