Genotypes of Metallo-beta-Lactamases Produced by Imipenem-Resistant Acinetobacter spp. Isolates from Clinical Specimens / 감염

ABSTRACT

BACKGROUND: Carbapenem-resistant Acinetobacter spp. are being isolated with increasing frequency from clinical sources. This study was designed to determine the resistance mechanism to carbapenems of Acinetobacter spp. isolates from patients of a tertiary care hospital in Busan, Korea. METHODS: Nonduplicated clinical isolates of Acinetobacter spp. resistant to carbapenems were collected during the period of 2000-2001 in Kosin Medical Center, Busan, Korea. Antimicrobial susceptibilities were tested by disk diffusion method. Carbapenem-resistant Acinetobacter spp. isolates were examined for metallo-beta-lactamase-production by modified Hodge and EDTA-disk synergy tests. For the detection of blaIMP-1 and blaVIM-2 genes, polymerase chain reactions (PCR) were performed, and the DNA sequences of amplified products were determined by using dideoxy- chain termination method. RESULTS: Among 21 clinical isolates of Acinetobacter spp. intermediate or resistant to carbapenems, 17 isolates showed positive reactions in modified Hodge and EDTA-disk synergy tests. Nine isolates showed positive reaction in PCR for the detection of blaIMP-1 genes, and 8 isolates showed positive reaction in PCR for the detection of blaVIM-2 genes. Sequencing of amplified products showed that they were blaIMP-1 or blaVIM-2 genes. CONCLUSION: Acinetobacter spp. isolates with carbapenem-resistance are not uncommon in Kosin Medical Center, and most of the carbapenem-resistant isolates acquired resistance by production of IMP-1 or VIM-2 metallo-beta-lactamases. The spread of metallo-beta-lactamase genes could compromise the future usefulness of carbapenem for the treatment of gram-negative bacilli infections.