Concern is growing for UTI antibiotic resistance

Check your last 10 patient charts. Chances are at least one patient reported a urinary tract infection (UTI). What was your chosen method of treatment?

Such infections are among the most common problems encountered by women's health clinicians. The estimated lifetime risk for experiencing a UTI is above 60% in women, and uncomplicated UTIs are one of the most common reasons for antibiotic use among otherwise healthy women.1,2

Just-presented research from Oregon State University in Corvallis suggests that more powerful antibiotics are used more frequently than necessary for treatment of such infections.3 The Oregon scientists recommend that healthcare providers and patients discuss the issues involved with antibiotic therapy and look to use of stronger drugs only if necessary.

To analyze national trends of antibiotic prescribing for cystitis, Oregon researchers looked at 1998-2009 data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, both nationally representative surveys of ambulatory and emergency department visits. Focusing on women above age 17, investigators examined trends in rates of cystitis visits and related antibiotic prescribing, and they used tests for trends.

Their analysis shows that annual rates for cystitis visits were stable (p = 0.45) between 1998 and 2009, with an average of 195 visits per 1,000 women. During this period, however, researchers report the proportion of visits with receipt of an antibiotic significantly increased.

Prescribing of first-line urinary anti-infectives such as trimethoprim/sulfamethoxazole, trimethoprim, fosfomycin, and nitrofurantoin remained constant (p = 0.10), yet quinolone use grew significantly (p < 0.01).

Overuse of the most powerful drugs, especially quinolone antibiotics, speeds the development of bacterial resistance to these drugs, say experts. Antibiotic resistance has gained global prominence with methicillin-resistant Staphylococcus aureus (MRSA), but resistance is a similar concern in many other bacteria as well.

"Because of higher levels of antibiotic resistance to older drugs in some regions, some doctors are now starting with what should be their second choice of antibiotic, not the first," said Jessina McGregor, PhD, assistant professor of pharmacy at the university in a statement accompanying the research findings. "We need to conserve the effectiveness of all these anti-infective medications as best we can."

Check guidance for use

The American College of Obstetricians and Gynecologists (ACOG) and the Infectious Diseases Society of America (IDSA) have issued guidance on antibiotic use for uncomplicated UTI treatment. ACOG released its guidance in 2008, with the IDSA recommendations published in 2011.2,4

Appropriate treatments listed by ACOG and IDSA include: trimethoprim/sulfamethoxazole (160/800 mg tablet twice daily for three days; not recommended in areas where local resistance rates exceed 20%); nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for five days); and fosfomycin trometamol (3 g powder single dose). ACOG also recommends trimethoprim alone (100 mg, twice daily for three days).5

According to the ACOG guidance, trimethoprim/sulfamethoxazole for three days is the preferred therapy. The IDSA guidance does not designate any of the four antimicrobials it recommends as preferred; however, it does note that fosfomycin has lower efficacy than other recommended agents.

While fluoroquinolones are highly effective in three-day regimens, drug resistance is increasing, and overuse will hinder fluoroquinolones' effectiveness against more important infections. The ACOG guidance advises against prescribing fluoroquinolones as first-line agents in areas where resistance prevalence to trimethoprim/sulfamethoxazole is low. (Look at ResistanceMap [www.cddep.org/resistancemap], a web-based collection of tools developed by the Washington, DC-based Center for Disease Dynamics, Economics & Policy, that allow exploration of more than 50 antimicrobial surveillance indicators from North America and Europe.) The IDSA recommendations call for fluoroquinolone use for acute cystitis only if a recommended antimicrobial cannot be used due to factors such as availability, allergy history, or tolerance.5

Tools in development

Oregon State University researchers are developing tools to help clinicians select the most appropriate antibiotic for individuals. Until they are available, providers can help select appropriate treatments for their patients by obtaining a detailed history of past medication use, becoming informed of local community levels of resistance, and improving levels of patient communication.

Cystitis is one of the most common reasons that many women see a doctor and are prescribed an antibiotic, noted McGregor. That is the reason that researchers are sounding the alarm on antibiotic resistance.

"Any infection can be serious if we don't have medications that can help stop it, which is why we need to preserve the effectiveness of all our antibiotics as long as we can," she stated.

References

  1. Foster RT Sr. Uncomplicated urinary tract infections in women. Obstet Gynecol Clin North Am 2008; 35(2):235-248.
  2. Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: a 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis 2011; 52:e103-e120.
  3. McGregor, Elman MR, Dent C, et al. National trends in antibiotic prescribing for uncomplicated cystitis in women. Presented at the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy. San Francisco, September 2012.
  4. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 91: Treatment of urinary tract infections in nonpregnant women. Obstet Gynecol 2008; 111(3):785-794.
  5. National Guideline Clearinghouse. Guideline synthesis: Diagnosis and management of lower urinary tract infection. Accessed at http://1.usa.gov/TjPywN.