Trimethoprim‐Sulfamethoxazole Resistance Among Urinary Coliform Isolates

• Published in: Journal of general internal medicine : JGIM 1999-10, Vol.14 (10), p.606-609
• Main Authors: Wright, Seth W., Wrenn, Keith D., Haynes, Mary Lou
• Format: Article
• Language: English
• Subjects: Adult; Anti-Infective Agents, Urinary - therapeutic use; Antibacterial agents; Antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antimicrobial agents; Bacteria; Biological and medical sciences; Case-Control Studies; Catheters; coliform organisms; Confidence intervals; Diabetes; emergency department; Emergency medical care; Enterobacteriaceae - drug effects; Enterobacteriaceae Infections - drug therapy; Female; Hospitalization; Humans; Internal medicine; Long term health care; Male; Medical records; Medical sciences; Original; Pharmacology. Drug treatments; Regression analysis; Retrospective Studies; Risk Factors; Trimethoprim Resistance; Trimethoprim, Sulfamethoxazole Drug Combination - therapeutic use; trimethoprim‐sulfamethoxazole resistance; Urinary tract diseases; urinary tract infection; Urinary tract infections; Urinary Tract Infections - drug therapy; Urinary Tract Infections - microbiology; Urogenital system; Variables
• ISSN: 0884-8734; 1525-1497
• DOI: 10.1046/j.1525-1497.1999.10128.x

OBJECTIVE: A large majority of urinary tract infections are caused by coliform organisms. Trimethoprim‐sulfamethoxazole (TMP‐SMX) resistance among uropathogens is increasing in many areas. The objective of this study was to determine risk factors for TMP‐SMX‐resistant coliforms in patients with urinary tract infections. DESIGN: Retrospective case‐control study. SETTING: Emergency department of a tertiary care university hospital. PATIENTS: We studied 448 emergency department patients aged 14 years or older with a urinary tract infection caused by a coliform organism. Cases consisted of all patients with a culture‐documented urinary tract infection caused by a TMP‐SMX‐resistant coliform, while control patients were those with a TMP‐SMX‐sensitive organism. MEASUREMENTS AND MAIN RESULTS: A univariate analysis of clinical variables associated with TMP‐SMX resistance was performed. Multiple logistic regression was performed to determine independent predictors of TMP‐SMX resistance. Resistance to TMP‐SMX was seen in 15% of isolates. Numerous variables were associated with TMP‐SMX resistance on the univariate screen. Independent predictors of resistance were diabetes (odds ratio [OR] 3.1; 95% confidence interval [CI] 1.2, 8.4), recent hospitalization (OR 2.5; 95% CI 1.1, 5.7), current use of antibiotics (OR 4.5; 95% CI 2.0, 10.2), and recent use of TMP‐SMX (OR 5.1; 95% CI 2.2, 11.5). When those with recent hospitalization were excluded from analysis, independent predictors were current use of any antibiotic (OR 3.5; 95% CI 1.4, 8.4) and recent use of TMP‐SMX (OR 5.9; 95% CI 2.4, 14.3). CONCLUSIONS: Coliforms resistant to TMP‐SMX are common in our emergency department. Diabetes, recent hospitalization, and the use of antibiotics, particularly the use of TMP‐SMX, are independent risk factors for TMP‐SMX resistance. Clinicians should consider these findings when deciding on antimicrobial therapy for patients with urinary tract infections.