Abstract

Objective: In this retrospective case-control study, it was aimed to determine risk factors and mortality rates associated with extended-spectrum b-lactamase (ESBL) production in bloodstream infections due to ESBL-producing Escherichia coli and Klebsiella pneumoniae, and to review preventive and control measures for decreasing ESBL production, and thus mortality.

Methods: Hospitalized patients or patients who have applied to the emergency service between January 1st 2010 and December 31st 2011, with positive blood cultures for E. coli and K. pneumoniae and fulfilling Centers for Disease Control and Prevention (CDC) criteria for bloodstream infection were included in the study. Subjects with ESBL-producing E. coli and K. pneumoniae infection were included in the case group while subjects infected with ESBL-negative organisms were included in the control group to make a comparison in terms of risk factors and mortality.

Results: During the study period, 310 patients with positive blood cultures for E. coli and K. pneumoniae and fulfilling CDC criteria for bloodstream infection were detected. 99 (31.9%) isolates from these patients were found as ESBL-positive. Chronic renal failure (p=0.001), decubitus wound/infection (p=0.015), hemodialysis (p=0.032), solid organ transplantation (p=0.001), surgical interventions within last 2 weeks (p=0.001), urological interventions within last 3 months (p=0.032), antibiotic usage within last three months (p=0.001), cephalosporin usage (p=0.001), steroid usage (p=0.001), and presence of ESBL-producing organisms in clinical specimens other than blood culture (p=0.001) were found as significant risk factors. No significant statistical difference was detected when these two groups were compared in terms of infection related mortality (p=0.919).

Conclusions: Determination of ESBL rates and risk factors in bloodstream infections will be beneficial for determining future treatment options and taking infection control measures.