Increased prevalence and clonal dissemination of multidrug-resistant Pseudomonas aeruginosa with the blaIMP-1 gene cassette in Hiroshima.

Objectives: The aim of this study was to evaluate the dissemination of metallo-beta-lactamase (MBL)-encoding genes among multidrug-resistant (MDR) Pseudomonas aeruginosa isolates recovered from major hospitals in the Hiroshima region.

Methods: During July to December from 2004 to 2006, a surveillance of eight major hospitals in the Hiroshima region identified 387 non-duplicate isolates resistant to imipenem (MIC >or= 16 mg/L). They were screened for resistance to amikacin (MIC >or= 64 mg/L) and ciprofloxacin (MIC >or= 4 mg/L) and MBL-encoding genes.

Molecular characterization of imipenem-resistant Pseudomonas aeruginosa in Hiroshima, Japan.

Pseudomonas aeruginosa showing resistance to imipenem were found in 100 of 1,058 strains (9.5%) from six hospitals (a-f) in Hiroshima City, Japan. Of the 100 strains, 14 (14%) were double disk synergy test positive using sodium mercaptoacetic acid disks, and 18 (18%) were bla(IMP-1) or bla(VIM-2) allele positive by polymerase chain reaction (PCR).