Catheter-associated urinary tract infection: new perspectives on old problems.

Foley catheterization remains the most common cause of nosocomial infection in medical practice. A new awareness of microbial ecology in various infectious diseases has led to a new understanding of the pathogenesis of this common infection control problem. Colonization of the catheter and its sequelae, including cystitis, result from a creeping adherent biofilm of bacteria ascending the luminal and external surfaces of the catheter and drainage system from a contaminated drainage spigot or from the urethral meatus. With further disruption of bladder defence mechanisms by selected bacteria colonizing the catheter, bacterial adherence to the bladder surface occurs and clinical cystitis becomes evident. An appreciation of bacterial strategies in catheter-associated infections will allow rational adaptation of infection control practices in this high risk patient population.