Prevalence of the blaIMP-1 gene in epidemiologically unrelated Pseudomonas aeruginosa isolates in Korea

Abstract number: P904

Jin J.S., Kim J.W., Choi C.H., Kim J., Lee Y.C., Seol S.Y., Cho D.T., Lee J.C.

Objectives: Resistance to carbapenems is reported increasingly in Pseudomonas aeruginosa worldwide. This study investigated the resistance mechanisms against carbapenems and the molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa isolates from a Korean hospital.

Methods: A total of 79 carbapenem-resistant P. aeruginosa isolates were obtained from a tertiary hospital, located in Daegu, Korea. Antimicrobial susceptibility was determined by agar dilution methods. Resistance to carbapenems was characterised by a carbapenemase activity test and PCR amplification. The oprD gene was screended by PCR and the expression of OprD protein in the outer membrane was determined by SDS-PAGE. PFGE was performed to determine the clonal relatedness of P. aeruginosa isolates.

Results: The resistance rates of metallo-b-lactamase (MBL) producers against b-lactams, aminoglycosides and fluoroquinolones were significantly higher than those of MBL non-producers. Of the 79 carbapenem-resistant P. aeruginosa isolates, two MBL genes were detected in 50 (63.3%) isolates: blaIMP-1 in 40 isolates and blaVIM-2 in 10 isolates. Both the blaIMP-1 and blaVIM-2 genes were inserted in the gene cassettes of class 1 integrons, which were located on the plasmids. The oprD gene was not amplified in the 43 isolates: 23 of the 50 MBL producers and 20 of the 29 MBL non-producers. The remaining 36 oprD-positive isolates showed the reduced expression of OprD in the outer membranes. PFGE suggests that carbapenem-resistant P. aeruginosa isolates originated from the diverse clones.

Conclusion: We report the first outbreak of IMP-1-producing P. aeruginosa in Korea. A high prevalence of plasmid-borne MBL genes in epidemiologically unrelated P. aeruginosa isolates suggests the possibility of the intra- and interspecies dissemination of the MBL genes.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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