Association of IS5 with divergent tandem blaCMY-2 genes in clinical isolates of Escherichia coli

Philip M. Kurpiel, Nancy D. Hanson

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Objective: To characterize a unique tandem bla CMY-2 gene arrangement found in two non-identical clinical strains of Escherichia coli. Methods: Both plasmid and chromosomal DNA were evaluated using PFGE, restriction digest analysis, plasmid profiling and Southern hybridization. bla CMY-2gene expression and gene copy number were evaluated by realtime PCR. Susceptibilities to selected β-lactam antibiotics were determined by agar dilution. Results: A tandem arrangement for bla CMY-2 was identified in both isolates and was the only arrangement for bla CMY-2 observed. These isolates had distinct PFGE and plasmid profiles. Each strain exhibited 2-fold higher bla CMY-2mRNA expression and up to 8-fold lower β-lactam susceptibility compared with a strain with a single copy of bla CMY-2. Conclusion: This is the first report of IS5 being associated with tandem bla CMY-2. IS5 has previously been associated with antibiotic resistance through tandem gene amplification. The unique tandem arrangement provides a mechanism for increased bla CMY-2expression.

Original languageEnglish (US)
Article numberdkr212
Pages (from-to)1734-1738
Number of pages5
JournalJournal of Antimicrobial Chemotherapy
Issue number8
StatePublished - Aug 2011

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


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