Epidemiology and Clinical Significance of Bacteriuria Caused by Vancomycin-Resistant Enterococci

Abstract

Background Vancomycin-resistant enterococci (VRE) have been important pathogen of nosocomial infections and isolated most commonly from urine specimens. However, the clinical significance of VRE bacteriuria remains unknown. The objectives of this study are to describe the frequency, related factors and outcomes of VRE bacteriuria, and to compare epidemiologic data and outcomes between the subgroups: symptomatic urinary tract infection (UTI), asymptomatic bacteriuria, and colonization.

Materials and Methods For patients with urine culture positive for VRE between August 1, 2002 and June 30, 2005, we collected clinical data and performed a retrospective analysis. According to Centers for Disease Control and Prevention (CDC), patients were classified as symptomatic UTI, asymptomatic bacteriuria, colonization and undetermined.

Results Total 144 episodes (2.88%), in 58 patients, of 5,008 urine specimens were positive for VRE during the study period. Frequency of antimicrobial exposure history, especially 3rd generation cephalosporin, indwelling urinary catheter, and ICU stay at the time of culture was high in patients with VRE bacteriuria. In VRE bacteriuria, symptomatic UTI was only 24.5%. Instead the majority of the patients (71.4%) was colonized in urine with VRE or had asymptomatic bacteriuria. In comparison between symptomatic UTI group and combined group of asymptomatic bacteriuria and colonization, most demographic data and clinical features including hospital day and mortality had no significant difference except one, male sex.

Conclusion Most patients with VRE bacteriuria were classified as asymptomatic bacteriuria and colonization and only one-fourth of patients with VRE bacteriuria require antibiotic therapy. Therefore, clinicians should decide to initiate antibiotic therapy after consideration of clinical significance of VRE bacteriuria.