Extended-spectrum β-lactamase-producing phenotype signifies a poor prognosis for patients with cefpodoxime-resistant Escherichia coli or Klebsiella pneumoniae bacteremia

Background and purpose: Bloodstream infections caused by multidrug-resistant Enterobacteriaceae are a major concern. This study explored the clinical impact of extended-spectrum β-lactamase (ESBL) production among cefpodoxime-resistant Escherichia coli and Klebsiella pneumoniae bacteremia. Methods: The medical charts and microbiological results of patients with cefpodoxime-resistant E. coli or K. pneumoniae bacteremia in a tertiary hospital in southern Taiwan between June 2003 and December 2006 were retrospectively reviewed. The clinical characteristics, medical histories, and clinical outcomes were evaluated. ESBL production was indicated by the double-disk synergy test. Results: 278 episodes of bacteremia caused by cefpodoxime-resistant K. pneumoniae or E. coli were identified, of which 115 (41%) were ESBL producing. Compared with non-ESBL-producing bacteremia, bacteremic episodes caused by ESBL producers were less often community acquired (4.3% vs 28.4%; p < 0.001). Underlying diabetes mellitus (48.7% vs 35.0%; p = 0.02), liver cirrhosis (22.6% vs 11.7%; p = 0.02), or uremia (21.7% vs 3.7%; p < 0.001) were more common in ESBL-producing bacteremia. In contrast, solid tumors were more frequent in non-ESBL-producing bacteremia (44.8% vs 27.8%; p = 0.004). Overall, patients with ESBL-producing bacteremia had higher disease severity indicated by a Pittsburgh bacteremia score ≥4, longer duration of hospital stay (51.1 days vs 31.9 days; p = 0.007), more admission to intensive care units (19.1% vs 8.0%; p = 0.006), and a higher mortality rate at 28 days (34.8% vs 23.9%; p = 0.03). Conclusion: ESBL production signifies a poor clinical outcome for patients with bacteremia caused by cefpodoxime-resistant E. coli or K. pneumoniae.