The clinical epidemiology and outcomes of bacteremic biliary tract infections caused by antimicrobial-resistant pathogens.

OBJECTIVES

The prevalence of antibiotic-resistant pathogens continues to increase steadily. The aim of this study was to analyze the changing patterns and risk factors of antibiotic resistance in patients with bacteremic biliary tract infections (BTIs). In addition, prognostic factors related to survival in patients with a bacteremic BTI were evaluated.

METHODS

Five hundred fifty-six biliary bacteremic events in 411 patients, treated from January 2000 to April 2010, were retrospectively analyzed. In addition, biliary bacteremic events were divided into nosocomial infections (N=396) and community-acquired infections (N=160).

RESULTS

The resistance rate to third-generation cephalosporin was higher in 2005-2009 (35 out of 140, 25%, vs. 72 out of 151, 47.7%). The prevalence of extended-spectrum β-lactamase-producing organisms of Escherichia coli and Klebsiella strains increased markedly from 2.3% (2 out of 86) in 2000-2004 to 43.9% (58 out of 132) in 2005-2009. Nosocomial infection, hospital days before bacteremia, previous hospitalization within 90 days, previous use of antibiotics within 90 days, and an indwelling biliary drainage catheter were found to be independently associated with antibiotic resistance. However, no association was found between antibiotic resistance and mortality in patients with biliary bacteremia.

CONCLUSIONS

Antibiotic resistance in bacteremic BTI has increased markedly during the past 10 years. Almost half of nosocomial bacteremic BTI caused by common Gram-negative pathogens during 2005-2009 (58.5%) could not be treated with third-generation cephalosporin. Clinical outcomes were found to be associated with bacteremia severity and underlying illness rather than antibiotic resistance.