Diversity of Integrons Carrying blaVIM-2 Cassette in Pseudomonas spp. and Acinetobacter spp..
10.5145/KJCM.2012.15.4.131
- Author:
Jonghwa YUM
1
;
Hee Bong SHIN
;
Dongeun YONG
;
Yunsop CHONG
Author Information
1. Department of Clinical Laboratory Science, College of Nursing and Healthcare Sciences, Dong-eui University, Busan, Korea. auxotype@deu.ac.kr
- Publication Type:Original Article
- Keywords:
Gram-negative bacilli;
Integron;
Metallo-beta-lactamase
- MeSH:
Acinetobacter;
Agar;
Anti-Infective Agents;
Integrons;
Introns;
Korea;
Lifting;
Polymerase Chain Reaction;
Pseudomonas;
Recombination, Genetic
- From:Korean Journal of Clinical Microbiology
2012;15(4):131-138
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Metallo-beta-lactamase-mediated carbapenem resistance has been increasingly reported in Pseudomonas, Acinetobacter and other Gram-negative bacilli (GNB) in many countries. A few studies showed highly variable structure of MBL-gene cassette-carrying integrons. The aim of this study was to determine the structure of blaVIM-2-carrying integrons in Pseudomonas and Acinetobacter. METHODS: blaVIM-2-carrying GNB were isolated at a Korean hospitals during the years 1995-1999 and 2005. The size of blaVIM-2-carrying integrons was estimated by the PCR products. Representative integrons were sequenced by the dideoxy-chain termination method. The MICs of antimicrobial agents were tested by the CLSI agar dilution methods. RESULTS: During the years 1995-1999 and 2005, the approximate size of the blaVIM-2-carrying class 1 integrons was 3-7 kb in 35 Pseudomonas isolates and 3-5 kb in 24 Acinetobacter isolates. The integrons carried one-five resistance gene cassettes in addition to the blaVIM-2 cassette. Other resistance gene cassettes found were blaOXA-1, aacA1, aac(6')-I, and aac(6')-II. Interestingly, sequences homologous to part of a putative class II intron were inserted into the recombination site of the last cassette in four of nine integrons. The class 1 integron from P. aeruginosa isolates had fused orf/IntI1 in a downstream leftward inverted repeat (IRi). CONCLUSION: According to period, the size and structure of blaVIM-2-carrying integrons are quite variable, but an identical one is also present in a different genus, indicating high mobility of the blaVIM-2 cassette and horizontal transfer of the whole integron. We suggest that the class 1 integron containing the blaVIM-2 gene is spreading horizontally among Gram-negative bacilli and is undergoing continuous development in Korea.
