Risk factors for bloodstream infection caused by extended-spectrum β-lactamase–producing Escherichia coli and Klebsiella pneumoniae: A focus on antimicrobials including cefepime

Abstract

Extended-spectrum β-lactamase (ESBL)-producing pathogens represent increasing challenges to physicians because of rising prevalence, high mortality, and challenging treatment. Identifying high risks and early appropriate therapy is critical to favorable outcomes. This is a 5-year retrospective case-case-control study performed at the Detroit Medical Center on adult patients with bloodstream infection (BSI) caused by ESBL-producing and non-ESBL-producing Escherichia coli or Klebsiella pneumoniae, each compared with uninfected controls. Data were collected from December 2004-August 2009. Multivariate analysis was performed using logistic regression. Participants included 103 patients with BSI caused by ESBL-producing pathogens and 79 patients with BSI caused by pathogens that did not produce ESBLs. The mean age of patients in the ESBL group was 67 years; of the patients, 51% were men, 77% were black, and 38% (n= 39) died in hospital. The mean age of patients in the non-ESBL group was 58 years; of the patients, 51% were men, 92% were black, and 22% (n= 17) died in hospital. On multivariate analysis, predictors of BSI caused by ESBL-producing pathogens included central venous catheter (odds ratio [OR], 29.4; 95% confidence interval [CI], 3.0-288.3), prior β-lactam-/β-lactamase-inhibitor therapy (OR, 28.1; 95% CI, 1.99-396.5), and prior cefepime therapy (OR, 22.7; 95% CI, 2.7-192.4). The only risk factor for BSI caused by non-ESBL-producing pathogens was urinary catheter insertion (OR, 18.2; 95% CI, 3.3-100.3). Prior antimicrobial therapy, particularly with β-lactam, was the strongest unique risk factor for BSI caused by ESBL-producing E coli or K pneumoniae.