ABSTRACT
A total of 209 clinical isolates of Pseudomonas (193Pseudomonas aeruginosa, 10 P. putida, 4P. stutzeri, and 2 P. fluorescensisolates) with reduced susceptibilities to imipenem and/or ceftazidime were subjected to PCR assays with primers specific forbla
IMP-1, bla
IMP-2,bla
VIM-1, and bla
VIM-2and sequence analysis to identify the metallo-β-lactamases (MBLs) prevalent among these organisms in Taiwan; and 21 isolates gave positive results. Five isolates including two P. putida and three P. stutzeri isolates were found to carrybla
IMP-1, and six isolates including fiveP. putida and one P. stutzeri isolates harboredbla
VIM-2. The remaining 10 isolates wereP. aeruginosa, and all were found to carry a novel variant of bla
VIM-2, designatedbla
VIM-3. There are only two nucleotide differences between bla
VIM-2 andbla
VIM-3, leading to two amino acid alterations. Our findings indicate that VIM-2 and its variant have become the most prevalent metalloenzymes in Pseudomonas in Taiwan. Southern hybridization with thebla
VIM-2-, bla
VIM-3-, and bla
IMP-1 -specific probes revealed that only two VIM-2-producing P. putida isolates appeared to carry the MBL gene on plasmids. Pulsed-field gel electrophoresis showed that six VIM-3-producing P. aeruginosa isolates and two IMP-1-producing P. stutzeri isolates were genetically related, suggesting that the spread of these MBL genes in Taiwan could be due to clonal dissemination as well as genetic exchange between different clones.
Comparative typing of Pseudomonas aeruginosa by random amplification of polymorphic DNA or pulsed-field gel electrophoresis of DNA macrorestriction fragments.
