Reclassification of urinary tract infections in critically III trauma patients: A time-dependent analysis

Background: Successful treatment of urinary tract infections (UTIs) in the trauma ICU requires early recognition and timely, appropriate antibiotic therapy. We evaluated the incidence and microbiology of UTIs stratified by days post-admission and risk factors. Methods: Prospective data were collected on 1,172 trauma patients admitted to the ICU over a two-year period. Infections were classified as Community Acquired (CA, ≤ 3 days), Early Nosocomial (EN, 4-6 days), Mid-Nosocomial (MN, 7-10 days) and Late Nosocomial (LN > 10 days). Criteria of the U.S. Centers for Disease Control and Prevention (CDC) were used for diagnosis. Results: Two hundred twenty patients (19%) were diagnosed with a total of 235 UTIs. Thirty-six patients were diagnosed with multiple UTIs. Escherichia coli, Enterococcus sp. and Candida sp. were the most common pathogens isolated. One thousand one hundred fifty-one patients had a Foley catheter placed (mean duration, 1 ± 11 days) with a CDC device-related infection rate (no. of catheter-associated UTIs/1000 catheter days) of 18. Patients admitted with a CA infection were significantly older (p <0.001) and had a higher mortality rate (39% vs. 15%, P = 0.001). Unanticipated pathogens in this group included Enterococcus, Candida, and Pseudomonas. Women were more likely to be admitted with a CA infection (5% vs. 1%, P <0.001) or acquire an NI infection (23% vs. 15%, p <0.001). Obesity was highly predictive of increased Foley catheter days, and thus UTI, by multivariate analysis (p <0.001). Conclusions: Escherichia coli was the most common pathogen in all nosocomial infection categories. Increased age, gender, and obesity, in addition to catheter-days, were significant risk factors for UTI in trauma patients. Specific risk factors may predispose patients to pathogens that are not ordinarily covered by usually-chosen antibiotic therapy.