532. Potential for misclassification of nosocomial urinary events in the neurologic patient population
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: The definitions used to classify nosocomial urinary events depend on an ability to convey urinary symptoms or manifest signs of infection. Altered mental status, bladder detrusor function, perception of pain, and thermoregulation may confound categorization into either symptomatic UTI (SUTI) or asymptomatic bacteriuria (ASB).
Method: The McGill University Health Centre Montreal Neurologic Hospital (MNH) is an 82 bed facility offering neurology, neurosurgical and critical care services. Global surveillance of hospital acquired infections (HAIs) was conducted on all wards at the MNH between August 17th and October 11th 2008 by chart review, review of all microbiology reports, review of all chest x-rays, and use of a clinical indicator form. The CDC/NHSN definitions for nosocomial events were used with a modified ASB definition allowing the inclusion of a single asymptomatic positive urine culture even without a urinary catheter. Chi-squared statistical test was used to compare proportions when appropriate.
Results: The incidence of HAIs for the MNH was 10.8/1000 patient-days. There were 41 HAIs in all, including 11 SUTIs and 17 ASBs. The rate of catheter-associated SUTIs at the MNH was estimated at 9.7 CA-UTI / 1000 catheter-days; 55% of SUTIs and 53% of ASBs were associated with urinary catheters. Ciprofloxacin was used in 71% of ASB. Of the ASBs 14 had positive urine leukocyte esterase and 9 had positive urinary nitrites.
ASB as opposed to SUTI was observed more frequently if there was noted cloudy urine (59% vs. 27%, p<0.11), foul urine (35% vs. 18%, p=0.92), incontinence (24% vs. 0%, p=0.09), or retention (24% vs. 0%, p=0.09).
Conclusions: Misclassification of SUTI as ASB may be underestimating true clinical UTIs. Local practices of culturing urine when not indicated may further confound colonization (ASBs) and true infection (SUTIs). Indications for urine culture should be better defined and an alternative definition may be required to properly categorize nosocomial events in this patient population.
Charles Frenette, MD, McGill University Health Centre, Montreal, QC, Canada, Marty Teltscher, MD, McGill University, Cote Saint Luc, QC, Canada and  M. S. Teltscher, None..
C. Frenette, None.