Dissemination of IMP-6 metallo-β-lactamase-producing Pseudomonas aeruginosa sequence type 235 in Korea.

Objectives To investigate the epidemiological traits of Pseudomonas aeruginosa clinical isolates producing metallo-β-lactamases (MBLs) in Korea. Methods A total of 386 non-duplicate P. aeruginosa clinical isolates were collected from Korea in 2009. Detection of MBL genes was performed by PCR. The genetic organization of class 1 integrons carrying the MBL gene cassette was investigated by PCR mapping and sequencing. The epidemiological relationships of the isolates were investigated by multilocus sequence typing and PFGE. Results Of 386 P. aeruginosa isolates, 30 (7.8%) isolates carried the blaIMP-6 gene and 1 (0.3%) isolate carried the blaVIM-2 gene. A probe specific for the blaIMP-6 gene was hybridized to an ∼950 kbp I-CeuI-macrorestriction fragment from all 30 isolates and a probe specific for the blaVIM-2 gene also hybridized to an ∼500 kbp I-CeuI-macrorestriction fragment from 1 isolate (BDC10). All 31 MBL-producing isolates shared an identical sequence type (ST), ST235, and they carried the same blaOXA-50 allelic type, blaOXA-50g. All MBL-producing isolates showed similar XbaI-macrorestriction patterns (similarity >85%), irrespective of MBL genotype. Conclusions P. aeruginosa ST235 carrying the chromosomally located blaIMP-6 gene is widely disseminated in Korea. [ABSTRACT FROM PUBLISHER]