Rethinking the Treatment of Urinary Tract InfectionsThursday, May 10th, 2012
In a surveillance study of more than 12 million bacteria, investigators at George Washington University found E. coli antimicrobial resistance to ciprofloxacin, the most commonly prescribed antimicrobial for urinary tract infections (UTI) in the United States, increased over fivefold from 2000 to 2010. In addition, nearly one in four isolates in 2010 were resistant to trimethoprim-sulfamethoxazole (TMP-SMX) (Bactrim®; Septra®), the second most commonly prescribed drug for this infection. Conversely, resistance to nitrofurantoin (Macrodantin®) and ceftriaxone (Rocephin™) showed minimal change.
E. coli antimicrobial resistance has been associated with a lower likelihood of clinical cure and increased risk of infection recurrence. Additionally, antimicrobial resistance significantly increases patient morbidity, costs of treatment, and rates of hospitalization. These findings are relevant because they indicate that E. coli resistance to two common drugs rose substantially over the last decade. For patients, this will ultimately translate into more expensive and sometimes more complex antimicrobial treatments.
E. coli accounts for 75% to 95% of UTIs, which are among the most common infections in humans. Half of all women will experience at least one UTI in their lifetime. E. coli antimicrobial resistance is a major factor in determining health outcomes in patients with UTIs. As antimicrobial resistance continues to increase, the remaining antimicrobial drug options have a higher likelihood of causing unwanted side effects such as gastrointestinal distress, nausea, and vomiting.
Clinical pearl: This study reveals that ciprofloxacin and TMP-SMX are no longer safe for outpatient UTIs. Safer antimicrobials for outpatient UTIs might be nitrofurantoin in patients without kidney insufficiency and amoxicillin/clavulanate and third-generation cephalosporins for all others. The authors also cite their concerns about the lack of new antimicrobial drug development, which has been declining for decades.
- Sanchez GV, Master RN, Karlowsky JA, Bordon JM. In vitro antimicrobial resistance of urinary Escherichia coli Isolates among U.S. outpatients from 2000 to 2010. Antimicrob Agents Chemother. 2012;56(4):2181-2183. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/22252813. Accessed May 5, 2012.