Characterization of a new integron containing VIM-2, a metallo-β-lactamase gene cassette, in a clinical isolate of Enterobacter cloacae

We report the first description of a new integron containing bla(VIM-2), a metallo-beta-lactamase gene from Enterobacter cloacae KU680, which was isolated from peritoneal fluid of a liver cirrhosis patient in South Korea. Antibiotic susceptibility testing, and modified Hodge and EDTA-disc synergy tests, were carried out to screen for metallo-beta-lactamase-producing strains. PCR and sequence analysis were used to identify and analyse the bla(VIM-2)-containing integron. The isolate was resistant to most beta-lactams, including imipenem, and demonstrated a positive modified Hodge and EDTA-disc synergy test, which are findings suggesting a metallo-beta-lactamase. Preliminary PCR-based experiments detected the metallo-beta-lactamase gene bla(VIM-2). Sequencing of the 4392 bp cloned PCR amplicon, containing the gene cassette bla(VIM-2), revealed the structure of the class 1 integron. The integron also contained additional insert gene cassettes, aadA, and unknown open reading frames 'orfII' and 'orfIII'. To the best of our knowledge, this is the first time that this metallo-beta-lactamase gene has been detected in E. cloacae.