Risk factors for urinary tract infection caused by Enterobacteriaceae with extended-spectrum beta-lactamase resistance in patients admitted to internal medicine departments.

Background: Extended-spectrum beta-lactamase (ESBL) resistance is a growing concern in and outside hospitals. Physicians often face a true clinical dilemma when initiating empirical antibiotic treatment in patients admitted to internal medicine departments.

Objectives: To determine the prevalence of risk factors for ESBL resistance in patients with urinary tract infection (UTI) admitted to internal medicine departments.

Methods: We conducted a retrospective analysis of the medical records of patients with UTI admitted to an internal medicine division in a community-based academic hospital over a 1 year period. We collected clinical, laboratory and imaging data that were available to the treating physician at admission. Outcome measures included ESBL resistance and death.

Results: Of the 6754 admissions 366 patients were included in the study. Hospitalization during the previous 3 months (odds ratio 3.4, P < 0.0001), residency in a long-term-care facility (OR 2.4, P = 0.004), and the presence of a permanent urinary catheter (OR 2.2, P = 0.015) were correlated to ESBL resistance with statistical significance. These risk factors were extremely prevalent in our patient cohort.

Conclusions: ESBL resistance is becoming prevalent outside hospital settings, and patients admitted to an internal medicine department with UTI frequently carry risk factors for harboring resistant bacteria. In such patients a high index of suspicion and early targeted antibiotic treatment for ESBL-producing Enterobacteriaceae may be justified.