Urinary tract infection caused by Enterococcus spp.: Risk factors and mortality. An observational study

Abstract

Background and objective: Urinary tract infections (UTIs) are frequently caused by Enterococcus spp. This work aims to define the risk factors associated with UTIs caused by Enterococci and to determine its overall mortality and predictive risk factors.

Materials and methods: A retrospective study was conducted on bacteremic UTIs caused by Enterococcus spp. among inpatients. We compared 106 inpatients with bacteremic UTIs caused by Enterococcus spp. vs. a random sample of 100 inpatients with bacteremic UTIs caused by other enterobacteria.

Results: A total of 106 inpatients with UTIs caused by Enterococcus spp. were analyzed, 51 of whom had concomitant positive blood cultures. Distribution by species was 83% E. faecalis and 17% E. faecium. The mean Charlson Comorbidity Index score was 5.9±2.9. Upon comparing bacteremic UTIs caused by Enterococcus spp. vs. bacteremic UTIs caused by others enterobacteria, we found the following independent predictors of bacteremic UTI by Enterococcus: male sex, obstructive uropathy, nosocomial infection, cancers of the urinary system, and previous antimicrobial treatment. Overall, inpatient mortality was 16.5% and was associated with a higher Sequential Organ Failure Assessment (SOFA) score (>4); severe comorbidities such as immunosuppression, malignant hemopathy, and nephrostomy; and Enterococcus faecium species and its pattern of resistance to ampicillin or vancomycin (p<0.05). Appropriate empiric antibiotic therapy was not associated with a better prognosis (p>0.05).

Conclusions: Enterococcus spp. is a frequent cause of complicated UTI in patients with risk factors. High mortality secondary to a severe clinical condition and high comorbidity may be sufficient for justifying the implementation of empiric treatment of at-risk patients.

Keywords: Bacteremia; Bacteriemia; Enterococcus spp.; Enterococos; Immunosuppression; Infección del tracto urinario; Inmunodepresión; Mortalidad; Mortality; Urinary tract infection.