Journal Article

Bacteremia Due to Extended-Spectrum β-Lactamase–Producing <i>Escherichia coli</i> in the CTX-M Era: A New Clinical Challenge

Jesús Rodríguez-Baño, Maria D. Navarro, Luisa Romero, Miguel A. Muniain, Marina de Cueto, María J. Ríos, José R. Hernández and Alvaro Pascual

in Clinical Infectious Diseases

Published on behalf of Infectious Diseases Society of America

Volume 43, issue 11, pages 1407-1414
Published in print December 2006 | ISSN: 1058-4838
Published online December 2006 | e-ISSN: 1537-6591 | DOI:
Bacteremia Due to Extended-Spectrum β-Lactamase–Producing Escherichia coli in the CTX-M Era: A New Clinical Challenge

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Background. Extended-spectrum β-lactamase (ESBL)–producing Escherichia coli, particularly those producing CTX-M types of ESBL, are emerging pathogens. Bacteremia caused by these organisms represents a clinical challenge, because the organisms are frequently resistant to the antimicrobials recommended for treatment of patients with suspected E. coli sepsis.

Methods. A cohort study was performed that included all episodes of bloodstream infection due to ESBL-producing E. coli during the period from January 2001 through March 2005. Data on predisposing factors, clinical presentation, and outcome were collected. ESBLs were characterized using isoelectric focusing, polymerase chain reaction, and sequencing.

Results. Forty-three episodes (8.8% of cases of bacteremia due to E. coli) were included; 70% of the isolates produced a CTX-M type of ESBL. The most frequent origins of infection were the urinary (46%) and biliary tracts (21%). Acquisition was nosocomial in 21 cases (49%), health care associated in 14 cases (32%), and strictly community acquired in 8 cases (19%). Thirty-eight percent and 25% of patients had obstructive diseases of the urinary and biliary tracts, respectively, and 38% had recently received antimicrobials. Nine patients (21%) died. Compared with β-lactam/β-lactamase–inhibitor and carbapenem-based regimens, empirical therapy with cephalosporins or fluoroquinolones was associated with a higher mortality rate (9% vs. 35%; P = .05) and needed to be changed more frequently (24% vs. 78%; P = .001).

Conclusions. ESBL-producing E. coli is a significant cause of bloodstream infection in hospitalized and nonhospitalized patients in the context of the emergence of CTX-M enzymes. Empirical treatment of sepsis potentially caused by E. coli may need to be reconsidered in areas where such ESBL-producing isolates are present.

Journal Article.  4596 words.  Illustrated.

Subjects: Infectious Diseases ; Immunology ; Public Health and Epidemiology ; Microbiology

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