Catheter-Associated Urinary Tract Infections in a Burn Unit: Epidemiological Study

Introduction: Besides burn wound infections, burned patients are also more susceptible to other types of nosocomial infections. Catheter-associated urinary tract infections (CA-UTI) are one of the most common infections in this context, responsible for high morbidity, increased hospital stay and associated costs. The aim of this study was to characterize catheter-associated urinary tract infections in hospitalized burn patients and evaluate the frequency of microbiologic agents responsible for these infections. Material and Methods: Retrospective study, performed in a Burn Center (Coimbra Burns Unit) of a University Hospital (Centro Hospitalar e Universitario de Coimbra, Portugal – CHUC), based in the clinical data and urine cultures of burned patients who have performed at least once this exam between 1 January 2010 and 31 December 2014. Different variables such as date of infection, general characteristics of the population and the responsible pathogen were analyzed. Infections were further categorized taking into account the existence of previous episodes of CA-UTI, thereby defining primary infection, re- infection, relapse and over-infection. Results: Between January 2010 and December 2014, 213 CA-UTI were diagnosed in 143 patients. The most common uropathogens were E. coli (27.2%), Enterococcus faecalis (20.2%), Pseudomonas spp. (13.1%), Candida spp. (12.1%), Klebsiella spp. (10.8%) and Acinetobacter baumannii (9.9%). The most common microorganisms varied significantly depending on the gender of the patient. The CA-UTI analyzed corresponded to 143 primary infections, 44 reinfections, 17 relapses and nine over-infections. Relapse corresponded to 11% of infections in males and 5.7% in females and was significantly more frequent in infections due to Acinetobacter baumannii. Discussion/Conclusion: Catheter-associated urinary infections are common in intensive care units, particularly at Burn Units. The most common pathogens identified were similar to those reported in the literature. Pathogens responsible for polymicrobial infections were similar to those in monomicrobial infections, probably due to the short-term nature of urinary catheterization. Infections by Acinetobacter baumannii showed high susceptibility to relapse, which is probably related to its multi-drug resistance, common in this pathogen. The high relapse rate detected in males is probably related to the greater frequency of Acinetobacter baumannii infections in this gender. Candiduria was more frequent in the context of reinfection and over-infection, probably due to disruption of bacterial flora secondary to previous systemic antibiotics.