[Factors associated with extended-spectrum betalactamases-producing organisms among patients with urinary tract infections: a prospective cohort study].

Background: Urinary tract infections (UTIs) caused by extended-spectrum betalactamases (ESBL) are an increasingly common problem.

Aim: To develop an association model to allow an early detection of ESBL-producing microorganisms.

Methods: A prospective observational cohort study was undertaken among patients admitted with a diagnosis of culture-proven UTI to the Internal Medicine Ward of the Hospital Naval Almirante Nef between February and November, 2011. Patients with polimicrobial cultures were excluded from analyses, which was undertaken using multiple logistic regression.

Results: Two-hundred and forty-nine patients were analysed and 35 (14%) presented an ESBL-producing microorganism. Seventy-one percent were female and the mean age was 70,7 ± 16,9 years. A history of a recent hospitalization (< 3 months) or institutionalization (p = 0.027), previous infections by an ESBL-producing bacteria (p < 0.001), recent antimicrobial use (p = 0.013) and metastatic cancer (p = 0.007) were independently associated with a current UTI with an ESBL-producing pathogen.

Discussion: Our findings are similar to those found in other populations. This tool offers assistance to clinicians who need to choose an appropriate antimicrobial therapy. This model needs to be validated prior to implementation.