Extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae:: Risk factors for infection and impact of resistance on outcomes

The prevalence of antibiotic resistance among extended-spectrum beta -lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae has increased markedly in recent years. Thirty-three patients with infection due to ESBL-producing E. coli or K. pneumoniae (case patients) were compared with 66 matched controls. Total prior antibiotic use was the only independent risk factor for ESBL-producing E, coli or K. pneumoniae infection (odds ratio, 1.10; 95% confidence interval, 1.03-1.18; P = .006). Case patients were treated with an effective antibiotic a median of 72 hours after infection was suspected, compared with a median of 11.5 hours after infection was suspected for controls (P < .001). ESBL-producing E. coli or K, pneumoniae infection was associated with a significantly longer duration of hospital stay and greater hospital charges (P = .01 and P < .001, respectively). Finally, many ESBL-producing E. coli and K, pneumoniae isolates were closely related. ESBL-producing E. coli and K. pneumoniae infections have a significant impact on several important clinical outcomes, and efforts to control outbreaks of infection with ESBL-producing E. coli and K. pneumoniae should emphasize judicious use of all antibiotics as well as barrier precautions to reduce spread.