The diverse integron structures disseminating VIM genes in Poland
Abstract number: 1134_01_5
Patzer J.A., Toleman M.A., Grzesik A., Dzierzanowska D., Walsh T.R.
Recently we have characterized a novel blaVIM-4 metallo-beta-lactamase (MBL) gene cassette from clinical strains isolated from hospitalized children in Warsaw, Poland. This novel gene cassette was harboured on class 1 integron and found in 11 strains of Pseudomonas aeruginosa with various PFGE patterns. The aim of this study was to genetically examine other carbapenem-resistant P. aeruginosa and P. putida clinical strains for similar integrons.
Phenotypic screening involved the MBL Etest strip (AB BIODISK). Biochemical analysis used crude extrats examining imipenem (IMP) and meropenem (MEM) hydrolysis preincubated with 20 mM EDTA. PCR analysis was performed using primers specific for blaIMP and blaVIM genes and class 1 integrons. Sequencing was carried out using Perkin-Elmer Biosystems 377 DNA sequencer and analysed using DNAstar.
The Etest produced for the majority of isolates a positive phenotypic test for MBL: IMP MIC > 256 mg/l; IMP/EDTA 18 mg/L. Isolates were resistant to all beta-lactams, and some additionally to aminoglycosides. The crude extracts of isolates showed hydrolysis of IMP and MEM, which were inhibited over 90% with EDTA. Screening for MBL using PCR analysis gave a positive result for the presence of the blaVIM gene. Two isolates of P. putida had an integron containing MBL gene blaVIM-4/blaVIM-4 partial repeat, then aacA4 (or aadB), OXA-2, orfD followed by qacEdelta1. P. aeruginosa isolate 266/03 had restriction pattern of blaVIM-4 as previously isolated in our hospital. Two P. aeruginosa isolates: 414/03 from our hospital and 303/03 from other hospital in Warsaw, had MBL gene blaVIM-2 as isolated previously in Warsaw. However, they had different additional genes within the class 1 integron.
Since 1998, P. aeruginosa strains with blaVIM-4 MBL genes have become endemic in children hospitalized in our institute. The source of blaVIM-4 gene cassette are probably the P. putida strains. Diverse integrons found in P. putida and P. aeruginosa isolates are responsible for the spread blaVIM genes in Poland.
|Session name:||XXIst ISTH Congress|
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