Factors associated with catheter-associated urinary tract infections and the effects of other concomitant nosocomial infections in intensive care units

Background: Catheter-associated urinary tract infections (CAUTIs) are the most common nosocomial infections in intensive care units (ICUs). The objectives of this study were to describe the incidence, aetiology, and risk factors of CAUTIs in ICUs and to determine whether concomitant nosocomial infections alter risk factors. Methods: Between April and October 2008, all adult catheterized patients admitted to the ICUs of Zonguldak Karaelmas University Hospital were screened daily, and clinical and microbiological data were collected for each patient. Results: Two hundred and four patients were included and 85 developed a nosocomial infection. Among these patients, 22 developed a CAUTI alone, 38 developed a CAUTI with an additional nosocomial infection, either concomitantly or prior to the onset of the CAUTI, and 25 developed nosocomial infections at other sites. The CAUTI rate was 19.02 per 1000 catheter-days. A Cox proportional hazard model showed that in the presence of other site nosocomial infections, immune suppression (hazard ratio (HR) 3.73, 95% CI 1.47-9.46; p = 0.006), previous antibiotic usage (HR 2.06, 95% CI 1.11-3.83; p = 0.023), and the presence of a nosocomial infection at another site (HR 1.82, 95% CI 1.04-3.20; p = 0.037) were the factors associated with the acquisition of CAUTIs with or without a nosocomial infection at another site. When we excluded the other site nosocomial infections to determine if the risk factors differed depending on the presence of other nosocomial infections, female gender (HR 2.67, 95% CI 1.03-6.91; p = 0.043) and duration of urinary catheterization (HR 1.07 (per day), 95% CI 1.01-1.13; p = 0.019) were found to be the risk factors for the acquisition of CAUTIs alone. Conclusions: Our results showed that the presence of nosocomial infections at another site was an independent risk factor for the acquisition of a CAUTI and that their presence alters risk factors.