Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae bloodstream infection: risk factors and clinical outcome

Abstract

Objectives. To study the risk factor for nosocomial bacteremia caused by Escherichia coli or Klebsiella pneumoniae producing extended-spectrum beta-lactamase (ESBL) and the influence on patient outcome. Design. Retrospective, single-center study of consecutive bacteremic patients. Settings. A university-affiliated teaching hospital. Patients. A total of 85 patients with nosocomial bacteremia due to E. coli or K. pneumoniae were enrolled. Intervention. None. Measurements and main results. The demographic characteristics and clinical information including treatment were recorded upon review of patients' records. The primary end point was hospital mortality. Twenty-seven percent of isolates produced ESBLs. Previous treatment with 3rd-generation cephalosporins was the only independent risk factor for bacteremia due to ESBL-producing pathogens [odds ratio (OR) 4.146, P=0.008]. Antibiotic treatment was considered appropriate in 71 cases (83%), and failed in 23 patients (27%). Twenty-one patients (25%) died in the hospital. Antibiotic treatment failure was the only independent risk factor for hospital mortality (OR 15.376, P=0.001). Inappropriate antibiotic treatment might lead to significantly higher mortality rate (7/14 vs 14/71, P=0.016). Patients treated with imipenem were more likely to survive while those receiving cephalosporin treatment tended to have a poorer outcome (1/19 vs 14/40, P=0.023). Conclusions. More judicious use of cephalosporins, especially 3rd-generation cephalosporins, may decrease ESBL-producing E. coli or K. pneumoniae bacteremia, and also improve patient outcome.