Identification of CTX-M β-lactamases in Escherichia coli from hospitalized patients and residents of long-term care facilities

Carl Urban, Noriel Mariano, Patricia A. Bradford, Margareta Tuckman, Sorana Segal-Maurer, Wehbeh Wehbeh, Louise Grenner, Rita Colon-Urban, Brian Johnston, James R. Johnson, James J. Rahal

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32 Scopus citations


Bacteria harboring CTX-M extended-spectrum β-lactamases (ESBLs) have been identified worldwide, with most reports coming from regions outside North America. We have identified CTX-M enzymes in 31% of ESBL-positive Escherichia coli isolates from our hospital and more than half (53%) of the isolates from associated long-term care facilities. Approximately 3/4 of all CTX-M-bearing isolates were from urine specimens, with a predominance of CTX-M-15. A large proportion of such isolates were nonsusceptible to levofloxacin, trimethoprim/sulfamethoxazole, and all β-lactam antimicrobials with the exception of the carbapenems, requiring carbapenem therapy for acute urinary tract infection or urinary tract-related sepsis. CTX-M β-lactamases have emerged within our location, and detection of bacteria harboring these enzymes in the clinical microbiology laboratory remains problematic because molecular methods are needed for their identification.

Original languageEnglish (US)
Pages (from-to)402-406
Number of pages5
JournalDiagnostic Microbiology and Infectious Disease
Issue number4
StatePublished - Apr 2010

Bibliographical note

Funding Information:
The study was supported by the BMA Medical Foundation , the Beatrice Snyder Foundation , NIH grant GM008722-07 (MARC-NIGMS-RCU), and the Office of Research and Development, Medical Research Service, Department of Veterans Affairs (J.R.J.) .


  • Antimicrobial resistance
  • CTX-M-15 β-lactamase
  • Escherichia coli infections
  • Long-term care facilities


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