Risk factors for enterococcal urinary tract infection and colonization in a rehabilitation facility.

BACKGROUND

We attempted to define the risk factors for urinary tract acquisition of enterococcus in a 155-bed rehabilitation facility in Southeastern Michigan by performing a prospective, case-controlled observational study.

METHODS

All cases were identified from daily review of microbiologic records of urine culture results. All urinary isolates of enterococcus species, whether representing infection or colonization, were saved on agar plates for subsequent pulsed-field gel electrophoresis. Thirty-five percent of urinary tract isolates were due to enterococcal species compared with 5% to 15% in adjacent acute-care facilities. A control was defined as the next patient with a nonenterococcal urinary isolate.

RESULTS

No differences were found between cases and controls with respect to age, sex, admitting diagnosis, voiding habits, symptoms, laboratory values, geographic location, caregivers, or urinary infection versus colonization.

CONCLUSIONS

Prior antibiotic use was more frequent in the patients colonized or infected with enterococcal isolates (78% vs 41%). No evidence was found for a single clone of enterococcal isolates in our facility by DNA analysis, suggesting that the acquisition of enterococcus in the urinary tract was endogenous.