Imipenem-resistant Achromobacter xylosoxidans carrying blaVIM-2-containing class 1 integron

We characterized seven isolates of imipenem-resistant Achromobacter xylosoxidans that were isolated from patients hospitalized in the intensive care unit at a tertiary hospital in Korea during 2001 to 2003. From the analysis with an isoelectric focusing, polymerase chain reaction, and sequencing methods, all isolates were found to produce VIM-2, OXA-30, and chromosomal AmpC β-lactamase with a pI of 8.4. They showed a similar antibiogram, which were resistant to all tested aminoglycosides as well as β-lactams including imipenem (16-32 mg/L) and aztreonam (128 mg/L), and a same DNA fingerprinting pattern by random amplified polymorphic DNA analysis, suggesting that these originated from a single clone. From the analysis of integron structure carried by an isolate of A. xylosoxidans CBU1760, blaVIM-2 was found to be part of a gene cassette carried on a class 1 integron (3.4 kb) containing three aacA4 gene cassettes. This is the first report of blaVIM-2 in A. xylosoxidans.