Epidemiology and risk factors for extended-spectrum beta-lactamase-producing organisms: a case control study at a tertiary care center in Lebanon

Abstract

Background: Infections caused by extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacilli constitute a growing problem worldwide. At the American University of Beirut Medical Center (AUBMC), we have observed a significant rise in the rates of ESBL-producing organisms over the past 5 years.

Methods: Using a case control study design, we compared 99 patients with infections caused by ESBL-producing Escherichia coli and Klebsiella species and 99 frequency-matched controls from which ESBL-nonproducing isolates were recovered at AUBMC.

Results: The most notable risk factor for acquiring infections with ESBL-producing organisms was antibiotic consumption within 30 days of the infection (OR, 7.06; 95% CI: 3.27-15.24), with third-generation cephalosporins being associated with the highest risk (OR, 28.4; 95% CI: 3.7-215.8). Other risk factors included recent surgery, presence of a urinary catheter, and need for mechanical ventilation. Moreover, cases had a longer mean duration of hospitalization and were more likely to have relapse of their infection than controls.

Conclusions: Recent antibiotic use is by far the most important predisposing factor to infection with ESBL-producing organisms. Such infections are associated with prolonged hospital stay and increased morbidity. Attention should be redirected toward the unjustified liberal use of broad-spectrum antibiotics both in the hospital and in the community.