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American Public Health Association
133rd Annual Meeting & Exposition
December 10-14, 2005
Philadelphia, PA
APHA 2005
4183.0: Tuesday, December 13, 2005 - Board 7

Abstract #115269

Urine culture susceptibility reports may be misleading: Cultured patients may be different than the majority treated empirically

Rebecca R. Roberts, MD, Rajiv Patel, BA, MSIII, Linda M. Kampe, RHIA, Fauzia Abbasi, MD, Kendra Larkin, MD, Mahita Bobba, BS, Ibrar Ahmad, BS, and Babak Saadatmand, MD. Department of Emergency Medicine, Stroger Hospital of Cook County/Rush University, 1900 W. Polk St. 10th floor, Chicago, IL 60612, 312-864-0075, rroberts@ccbh.org

Hospital antibiograms summarize the antibiotic susceptibility patterns for organisms recovered from cultures. They are used to guide empiric antibiotic therapy. Cultures are currently recommended only for those likely to have resistant or complicated infections. Therefore, existing antibiograms may not reflect the antibiotic susceptibility in lower risk patients. An antibiogram based on high risk patients may cause proscribing of broad spectrum antibiotics when they are not needed, causing increased community antimicrobial resistance. Our two research questions were: 1. Do patients who receive urine cultures (UC) have more risk factors for antimicrobial resistant infection than those who are not cultured? 2. Do empiric treatment decisions reflect the antimicrobial susceptibilities of those we do culture? Methods: Electronic and paper medical records for consecutive adults treated for UTI were abstracted for demographic, co-morbidity, severity of illness, laboratory, UC, diagnosis, and treatment. Results: The demographics for 655 patients were: mean age: 40; male: 14%, pyelonephritis: 20%, underlying GU co-morbidity/device: 19%, diabetes: 12%, cancer: 3%, renal stones: 8%. Of 33% of patients who received UC (95%CI: 29-37), 44% were positive. Those who received UC were significantly older, and more likely to be male, diabetic, suffer from co-morbidities, and to have higher BUN and creatinine levels; P < 0.001. Positive UC was significantly associated with male gender and pyelonephritis; P < 0.001. Among 73 susceptibilities, 9 (12%) were resistant to first-line drugs and required fluoroquinolones. Fourteen organisms (19%; 95% CI: 10-28) were resistant to fluoroquinolones, and 3 (4%; 95% CI: 0-8) were resistant to nitrofurantoin. Of the 94% of patients who received empiric antibiotic treatment: 361 (55%) were treated with fluoroquinolones, 214 (33%) received trimethoprim/sulfa, 32 (5%) received beta-lactams, and 6 (<1%) received nitrofurantoin.

Conclusions: While 55% of patients received fluoroquinolones, this decision may be based on an antibiogram reflecting patients with higher prevalence of resistance or adverse outcomes than those empirically treated. The 33% with UC had higher rates of resistant infection predictors. Even the high-risk antibiogram did not explain the high use of fluoroquinolones; only 2% of the sample had a documented fluoroquinolone requirement. The older, less expensive nitrofurantoin had better activity against recovered organisms; but was rarely used. Over 3 years, our antibiogram reflected a 10% reduction in the effectiveness of fluoroquinolones for urinary pathogens. This is possibly due to excessive use in ambulatory low-risk patients. We suggest that surveillance cultures in low-risk UTI patients, may promote improved antimicrobial choices, and cost-savings.

Learning Objectives:

Keywords: Practice Guidelines, Antibiotic Resistance

Presenting author's disclosure statement:

I wish to disclose that I have NO financial interests or other relationship with the manufactures of commercial products, suppliers of commercial services or commercial supporters.

Medical Care Section Poster Session #4

The 133rd Annual Meeting & Exposition (December 10-14, 2005) of APHA