Objective: To study the risk factors for bacteremia caused by Escherichia coli (E. coli) or Klebsiella pneumoniae (K. pneumoniae) producing extended-spectrum beta-lactamase (ESBL) and their outcome.
Methods: A case-control study was conducted in King Abdul-Aziz National Guard Hospital, Al-Ahsa, Kingdom of Saudi Arabia from January 2006 through December 2007. All adult patients for whom culture results were positive for E. coli or K. pneumoniae were eligible. Twenty-nine patients with ESBL producing bacteremia (cases) were compared with 80 patients with non-ESBL producing bacteremia controls. Hospital mortality was the primary end point. Univariable and multivariable logistic regression were performed to analyze risk factors for ESBL bacteremia and its 30-day mortality.
Results: A total of 109 patients with bacteremia were enrolled that included 29 cases and 80 controls. Forty-nine percent of the patients were male. The mean age was 60.2+/-21.1 years. Nosocomial infection was the only independent risk factor for bacteremia due to ESBL-producing pathogens (odds ratio [OR] 3.40, 95% confidence interval [CI] 1.14-8.44, p=0.02). Overall 30-day mortality was 22%, and was similar in both groups. The nosocomial infection (OR 3.20, 95% CI 1.48-6.94, p=0.01), presentation with septic shock (OR 48.88, 95% CI 6.01-397.32, p=0.004), and intensive care unit care (OR 7.40, 95% CI 1.94 -28.34, p=0.001) were the independent risk factors for 30-day mortality.
Conclusion: The ESBL rate is high in our study among the bacteremic patients. Nosocomial infection is identified both as a risk factor for ESBL bacteremia and mortality.