Investigation of beta-lactamase-producing multidrug-resistant Pseudomonas aeruginosa isolated from non-tertiary care hospitals in Korea.

A total of 2,280 nonduplicate clinical isolates of Pseudomonas aeruginosa, obtained nationwide from Korean non-tertiary care hospitals from 2002 to 2005, were identified and their susceptibilities to aminoglycosides, antipseudomonal penicillins, carbapenems, cephalosporins, monobactams, and quinolones were studied, together with their production of beta- lactamases. Using disk diffusion and minimum inhibitory concentration tests, it was found that 2.9% of isolates were multidrug-resistant (MDR) P. aeruginosa. An EDTA-disk synergy test, PCR amplification with specifically designed primers, and direct sequencing of the PCR products showed that the blaOXA-10, blaVIM-2, blaOXA-2, blaOXA-17, blaPER-1, blaSHV-12, and blaIMP-1 genes were carried by 34.3%, 26.9%, 3.0%, 3.0%, 1.5%, 1.5%, and 1.5% of 67 MDR P. aeruginosa isolates, respectively. The prevalence of MDR P. aeruginosa was three-fold higher, compared with that from the United States. More than two types of beta-lactamase genes were carried by 10.4% of isolates. The most prevalent beta-lactamase genes were blaVIM-2 and blaOXA-10. This study is the first description of MDR P. aeruginosa from non-tertiary care hospitals in Korea and the coexistence of the blaOXA-10 gene with blaVIM-2, blaIMP-1, or blaPER-1 in these clinical isolates.