Incidence and risk factors for acquiring nosocomial urinary tract infection in the critically ill

Purpose: A urinary tract infection (UTI) is the most common hospital-acquired infection. However, the epidemiology of intensive care unit (ICU)-acquired UTIs is not well defined. The objective of this study was to describe the incidence, risk factors, and clinical outcomes of ICU-acquired UTIs.

Materials and methods: All patients admitted to adult multidisciplinary ICUs in the Calgary Health Region (CHR, population approximately 1 million) during May 1, 1999 to April 30, 2000 were studied using a cohort design.

Results: A total of 1,158 admissions to a CHR ICU were 48 hours in duration or more. A total of 111 episodes of ICU-acquired UTI (defined as >10(5) CFU/mL of 1 or 2 organisms >48 hours after ICU admission) occurred in 105 (9%) patients and 5 (0.4%) had ICU-acquired bacteremic/fungemic UTIs for incidences of 11.3 and 0.5 UTIs per 1,000 ICU days, respectively. Significant independent risk factors for developing an ICU-acquired UTI as determined by a logistic regression model were female gender (adjusted odds ratio [OR(adj)], 2.31; 95% confidence interval [CI], 1.48-3.59) and natural logarithmic transformation of ICU length of stay (OR(adj), 3.96; 95% CI, 3.02-5.17). No differences in admitting vital signs, routine blood tests, APACHE II and TISS scores, or overall hospital mortality rate were observed among patients who developed an ICU-acquired UTI as compared with those who did not. The most common UTI etiologies were Enterococcus spp. (24%), Candida albicans (21%), and Escherichia coli (15%). Only 4 (3%) of the organisms were highly antibiotic resistant.

Conclusions: Nosocomial UTIs develop commonly in the critically ill and women and those with an extended ICU stay are at increased risk. Although ICU-acquired UTIs are markers of morbidity, they do not significantly increase mortality.