May 9, 2012

Antimicrobial Resistance Complicates UTI Prescribing

Washington, D.C.—Treatment for urinary tract infections (UTIs) is undergoing a change as bacterial resistance grows to both first- and second-line therapies, according to new research.

The study, published in the journal Antimicrobial Agents and Chemotherapy, found that E. coli antimicrobial resistance to ciprofloxacin, usually the gold standard for UTI treatment in this country, increased more than fivefold from 2000 to 2010. The news isn't much better for the second most prescribed antimicrobial: One in four isolates in 2010 were resistant to trimethoprim-sulfamethoxazole.

The study noted that half of all women have a UTI at least once in their lifetime and that the vast majority of infections, 75% to 95%, are caused by E. coli

"Our study is important because it shows that E. coli resistance to two common drugs to treat UTIs rose substantially over the last decade. For patients, this will ultimately translate into more expensive and sometimes more complex antimicrobial treatments," said Guillermo Sanchez, a graduate student in the physician assistant program at the George Washington University and primary author of the study.

Researchers warned that as resistance increases, the remaining options may be more likely to cause side effects such as gastrointestinal distress, nausea, and vomiting, so expect more questions from patients seeking relief.

One of the coauthors, Jose Bordon, MD PhD, AAHIVS, an infectious disease specialist at Providence Hospital in Washington, D.C., said the study "reveals that ciprofloxacin and TMP-SMX are no longer safe for outpatient urinary tract infection" and recommends that outpatient UTI be treated with nitrofurantoin in patients without kidney insufficiency and amoxicillin/clavulanate and third generation cephalosporins for others.

When resistance isn't an issue, ciprofloxacin remains the preferred treatment, according to a recently-published meta-analysis of UTI treatments. The Dutch study found ciprofloxacin and gatifloxacin appeared to be the most effective of the nine treatments from 10 studies compared and ranked. Amoxicillin-clavulanate appeared the least effective treatment, according to the research published in the journal Family Practice. No significant difference in adverse effects was noted.

U.S. Pharmacist Social Connect