Preventing Catheter-Associated Urinary Tract Infections

Laura A. Stokowski, RN, MS


February 03, 2009

CAUTI Surveillance

The most common clinical presentation for UTI is fever with positive urine culture, without other localizing findings.[1] Localizing signs and symptoms may never arise, or they may be difficult to recognize because of comorbid illness. Therefore, infection is often asymptomatic and is detected solely with a positive urine culture. Microbiological diagnosis usually requires the growth of at least 105 CFU/mL of an organism from a urine specimen collected aseptically from the catheter.[1] A urinary tract infection is not diagnosed on the basis of urine dip stick reactivity for nitrites and leukocytes.[11]

Currently, in many facilities, protocols for obtaining urine culture specimens from long-term urinary catheters direct the nurse to clamp the catheter to allow fresh urine to collect, and then withdraw urine from the sampling port of a triple-lumen catheter, using aseptic technique.[12] Mikel Gray, PhD, FNP, PNP, CUNP, CCCN, FAAN, Nurse Practitioner and Professor in the Department of Urology and School of Nursing at the University of Virginia in Charlottesville, recommends changing the catheter first and obtaining the urine sample from the fresh catheter. "The older the catheter, the more species of bacteria it is likely to harbor," asserts Gray. "Taking a culture from an old catheter usually produces multiple species, whereas urine from a new catheter will yield 1 or 2 predominant organisms that are causing the symptoms."

Many studies have compared these 2 methods of procuring urine cultures. Compared with old catheters, a consistent reduction was found in the number and types of microbes isolated from fresh catheters.[13,14,15] A sample taken from a new catheter is likely to represent the milieu of the bladder rather than that of the biofilm-coated catheter.[12] Because the new catheter contains fewer pathogens, treatment is less toxic and less costly.[15] Clinical and bacteriologic outcomes are improved when the catheter is changed before starting antibiotic therapy for symptomatic CAUTI.[16] "The patient will respond better to treatment," maintains Gray. On the basis of these findings, some institutions have changed their procedure for collecting urine culture samples.[12]


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