SAN FRANCISCO – Standardized, low-dose daptomycin is safe and effective for treating gram-positive urinary tract infections, a small observational study demonstrated.
"Very few existing studies evaluate daptomycin for the treatment of urinary tract infections (UTIs)," study investigator Hannah R. Palmer, Pharm.D., said in an interview at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy, where the poster was presented.
Hannah Palmer, Pharm.D.
"Although not FDA approved for this indication, this agent is routinely used at our hospital for UTIs due to drug-resistant gram-positive cocci. Based on the high urine concentrations of daptomycin, we hypothesized that even low, non–weight based standardized doses of 250 mg would be effective for the treatment of UTIs in all patients at our institution. This strategy simplifies treatment, decreases patient drug exposure and potential toxicity, as well as helps to maintain costs."
Dr. Palmer, infectious diseases clinical coordinator at St. Luke’s Episcopal Hospital, Houston, and her associates retrospectively evaluated 36 hospitalized patients who were treated with 250 mg daptomycin for UTIs from January 2010 to March 2012. They collected data regarding microbiologic and clinical cure, rates of relapse, reinfection, bacteremia, and adverse events.
She reported that vancomycin-resistant enterococcus (VRE) was isolated in 27 of the 36 patients (75%). Of these, 25 (93%) had daptomycin minimum inhibitory concentration values for VRE isolates that were greater than 1 mg/mL. Patients took daptomycin for a median of 5.5 days, and 35 patients (97%) achieved microbiologic and clinical cure with no evidence of relapse, reinfection, or bacteremia.
Although five patients did not have Foley catheters removed, they still demonstrated treatment success, she noted. One patient experienced an elevation in creatine phosphokinase, but no other adverse events related to daptomycin were observed.
"Our study is unique in that this is the largest population to date evaluated for the use of daptomycin for the treatment of UTIs," said Dr. Palmer, who is also with the University of Houston College of Pharmacy. "Only one previous study has been published that examines standardized low-dose daptomycin. That study is limited by a small population size of six patients."
She acknowledged certain limitations of the current study, including its retrospective, noncomparative design.
The meeting was sponsored by the American Society for Microbiology. The researchers stated that they had no relevant financial conflicts to disclose.