Unusual Urinary Pathogen Characterized

New findings could help guide management of vancomycin-resistant, ampicillin-sensitive E. faecalis.

SAN DIEGO—According to researchers, urine cultures yielding vancomycin-resistant, ampicillin-sensitive Enterococcus faecalis (VRASEF) may not always represent a true UTI, and the proper treatment is not well characterized.

VRASEF is not a common organism cultured from urine, and there is debate about how best to medically manage patients who are culture positive for the pathogen. The epidemiology, risk factors, and drug of choice to treat UTIs caused by these bacteria are not well documented.

Sandhya Nalmas, MD, and Suja Mathai, MD, of the division of infectious diseases at BethIsraelMedicalCenter in New Jersey, reviewed 31 charts of patients having positive cultures for VRASEF. The mean age of the patients was 67 years (range 31-95 years); 17 (55%) were female and 23 (74.2%) were African American. Among these 31 inpatients, only 18 (58%) met case definition for symptomatic UTI. Three patients (10%) had VRASEF colonization, three (10%) had asymptomatic bacteriuria, and seven (23%) did not have urinalyses.

Common comorbid conditions included renal insufficiency (12 patients), diabetes mellitus (10 patients), immunosuppression (nine patients) and malignancy (seven patients). The most common antibiotics used for treatment one month before positive urine cultures were levaquin (22 patients [71%]) and vancomycin (13 patients [42%]). There were no significant differences between UTI group and the non-UTI group in terms of age, sex, diabetes mellitus, renal insufficiency, nursing home residency, Foley catheter use, number of days hospitalized, and antibiotic treatments. Patients with UTIs, however, were more likely to have underlying malignancy compared with non-UTI patients.

No VRASEF bacteremias were observed in either group and among the 18 patients with UTIs, the researchers reported here at the annual meeting of the Infectious Diseases Society of America. Seven patients (38%) received linezolid, three (17%) received ampicillin, and seven (38%) receiving other antibiotics, such as doxycycline, primaxin, and levaquin. Patients with UTIs and diabetes mellitus were more often treated with linezolid compared with non-diabetic patients with UTIs. During the study period, four patients with UTIs died, but none of the deaths was related to the UTI.

“Whenever you see a urine culture that is positive for VRASEF it does not necessarily mean it is infectious,” Dr. Nalmas said. “Physicians need to categorize whether the patients really have UTIs versus a non-UTI. Depending on the organism and the sensitivity, we need to consider the appropriate drug. Just because we are using an expensive drug it doesn't mean it is going to clear better than if the patient was treated with simple ampicillin.”

The study underscores the importance of using antibiotics appropriately, which could help reduce development of multidrug resistant bacteria, she said.