Molecular mechanisms of carbapenem resistance in enterobacter cloacae clinical isolates from Korea and clinical outcome

Yangsoon Lee, Heekyeong Choi, Jong Hwa Yum, Girung Kang, Il Kwon Bae, Seok Hoon Jeong, Kyungwon Lee

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17 Citations (Scopus)


We investigated the molecular mechanisms of carbapenem resistance in clinical isolates of Enterobacter cloacae and their clinical characteristics. Nonreplicable E. cloacae isolates were recovered from six cancer patients and one patient with liver cirrhosis at a tertiary-care hospital in Korea between 2002 and 2009. Two patients who were considered to have a true infection caused by these microorganisms have died. All isolates produced AmpC β-lactamases, including ACT-1, ACT-2, MIR-3 and DHA-1, and CTX-M- or SHV-type extended-spectrum β-lactamase. Two isolates produced plasmid-borne VIM-2 carbapenemase. All probes specific for blaAmpC genes hybridized with I-CeuI chromosomal fragments were also recognized by a probe specific for 16S rDNA, suggesting a chromosomal location. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that a major outer membrane protein, OmpF, was absent in all isolates. PFGE of XbaI-digested DNA were considered to be unrelated. The results of our study suggest that the chromosomal AmpC β-lactamase with impermeability in E. cloacae clinical isolates implicated in reduced carbapenem susceptibility. Although carbapenem-resistant E. cloacae isolates were isolated in a few patients in our study, the clinical outcomes were grave. Therefore, the patients colonized or infected by carbapenemresistant E. cloacae isolates should gain attention of antibiotic therapy.

Original languageEnglish
Pages (from-to)281-286
Number of pages6
JournalAnnals of Clinical and Laboratory Science
Issue number3
Publication statusPublished - 2012

All Science Journal Classification (ASJC) codes

  • Medicine(all)


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