BACKGROUND: Urinary tract infection is the most common hospital acquired infection. The major associated cause is indwelling urinary catheters. Currently there are many types of catheters available. A variety of specialised urethral catheters have been designed to reduce the risk of infection. These include antiseptic impregnated catheters and antibiotic impregnated catheters. Other issues that should be considered when choosing a catheter are ease of use, comfort and the cost. OBJECTIVES: The primary objective of this review was to determine the effect of type of indwelling urethral catheter on the risk of urinary tract infection in adults who undergo short-term urinary catheterisation. SEARCH STRATEGY: We searched the specialised trials registers of the Cochrane Incontinence Group (November 2003) and the Cochrane Renal Group (February 2003). We also examined the bibliographies of relevant articles and contacted catheter manufacturer representatives for trials. SELECTION CRITERIA: All randomised and quasi randomised trials comparing types of indwelling urinary catheters for short-term catheterisation in hospitalised adults. Short-term catheterisation was defined as up to and including fourteen days, or other temporary short-term use as defined by the trialists. DATA COLLECTION AND ANALYSIS: Data were extracted by one reviewer and independently verified by a second reviewer. Disagreements were resolved by discussion. Data were processed as described in the Cochrane Handbook. Where data in trials were not fully reported, clarification was sought directly from the trialists (secondary sources were used to confirm results of one trial). MAIN RESULTS: Eighteen trials met the inclusion criteria involving 4237 hospitalised adults in 17 parallel group trials and 27,878 adults in one large cluster-randomised cross-over trial. Only three of the possible six comparisons were addressed in these trials: antiseptic impregnated catheters versus standard catheters (n=11 trials), antibiotic impregnated catheters versus standard catheters (n=1 trial) and comparison of different standard catheters (n=6 trials). The results of the antiseptic versus standard catheter trials differed according to the antiseptic used to impregnate the catheter. The antiseptic catheters were either impregnated with silver oxide or silver alloy. Silver oxide catheters were not associated with a statistically significant reduction in bacteriuria in short-term catheterised hospitalised adults but the confidence intervals were wide (RR 0.89, 95% CI 0.68 to 1.15). Silver alloy catheters were found to significantly reduce the incidence of asymptomatic bacteriuria (RR 0.36, 95% CI 0.24 to 0.52) in hospitalised adults catheterised for less than one week. At greater than one week catheterisation the risk of asymptomatic bacteriuria was still reduced with the use of silver alloy catheters (RR 0.67, 95% CI 0.50 to 0.90). The risk of symptomatic urinary tract infection was also found to be reduced with the use of silver alloy catheters (RR 0.60, 95% CI 0.50 to 0.73). The randomised cross-over trial of silver alloy catheters versus standard catheters was excluded from the pooled results because data were not available prior to crossover. The results of this trial indicated benefit from the silver alloy catheters and included an economic analysis that indicated cost savings of between 3.3 per cent and 35.5 per cent. One small trial investigated men post radical prostatectomy catheterised with antibiotic impregnated catheter versus standard catheters and found a lower rate of asymptomatic bacteriuria in the antibiotic group at less than one week of catheterisation (RR 0.36, 95% CI 0.18 to 0.73). The trial at less than one week found that the risk of bacteriuria was also less in the antibiotic impregnated catheter group (RR 0.36, 95% CI 0.18 to 0.73); however, at greater than one week the result was not significant (RR 0.94, 95% CI 0.86 to 1.03). One of 56 men in the antibiotic impregnated group had a symptomatic UTI compared with 6 of 68 who had standard catheters (RR 0.20, 9h 6 of 68 who had standard catheters (RR 0.20, 95% CI 0.03 to 1.63). Three trials compared two different types of standard catheters (defined as catheters that are not impregnated with antiseptics or antibiotics) to investigate infection but the results were not pooled because of the clinical and statistical heterogeneity between trials. Individual findings of the trials did not show whether or not one type of standard catheter reduced the risk of catheter related urinary tract infection compared to another type of standard catheter. Another three trials compared different types of standard catheters to investigate for adverse urethral effects in catheterised men. Once again the trials were not pooled due to significant heterogeneity; however, the results of the individual trials indicate a trend toward silicone catheters being less likely to result in adverse urethral effects in men. REVIEWER'S CONCLUSIONS: The results suggest that the use of silver alloy indwelling catheters for catheterising hospitalised adults short-term reduces the risk of catheter acquired urinary tract infection. Further economic evaluation is required to confirm that the reduction of infection compensates for the increased cost of silver alloy catheters.Catheters coated with a combination of minocycline and rifampin may also be beneficial in reducing bacteriuria in hospitalised men catheterised less than one week but this requires further testing. There was not enough evidence to suggest whether or not any standard catheter was better than another in terms of reducing the risk of urinary tract infection in hospitalised adults catheterised short-term. Siliconised catheters may be less likely to cause urethral side effects in men: however, this result should be interpreted with some caution as the trials were small and the outcome definitions and specific catheters compared varied.