[Analysis of class I integrons in metalloenzyme-producing Pseudomonas aeruginosa].

OBJECTIVE: To investigate class I integrons and integrated gene cassettes in metalloenzyme-producing Pseudomonas aeruginosa. METHODS: A total of 68 isolated clinical strains of Pseudomonas aeruginosa were subjected to PCR analysis with primers specific for bla(IMP-1) and bla(VIM). The positive strains then underwent examination for class I integrons and integrated gene cassettes with PCR with primers specific to class I integrase ((IntI)1) and integrated gene cassettes, followed by sequence analysis for some of the positive strains. RESULTS: Only 1 isolated strain showed positive results for both bla(IMP-1) and bla IntI1 detection. Fifty-five strains were positive for bla(VIM), including 26 positive for bla (IntI)1. Of the 26 bla (IntI)1-positive strains, only 18 contained integrated gene cassettes, which were classified into 5 types according to agarose gel electrophoresis. CONCLUSION: It is the first time to identify IMP-1-producing Pseudomonas aeruginosa carring bla(Int)1 in West China. The class I integrons were widespread in these Pseudomonas aeruginosa and 69.2% of them carry the gene cassettes. These findings provide useful insights into the clinical spread of these drug-resistant genes.