Integron-mediated multi-resistance in AmpC beta-lactamase from clinical isolates of Esecherichia coli and Klebsiella pneumoniae
Objective To investigate integron-mediated multi-resistance in AmpC beta-lactamase from clinical isolates of Esecherichia coli and Klebsiella pneumoniae. Methods Five strains of Esecherichia coli and Klebsiella pneumoniae producing AmpC beta-lactamase were isolated from patients hospitalized in respiratory ward from January 2002 to May 2004. Antibiotics sensitivity was detected by E-test method, electroporation, and multi-resistance plasmids were screened and isolated by extracting transformant plasmids. Inserted gene cassettes of class 1 integron were amplified and analyzed by PCR and DNA sequencing. Results All 5 strains of Klebsiella pneumoniae and Esecherichia coli producing AmpC beta-lactamase transferred cefoxitin-resistance to recipient by electroporation. In four of them AmpC beta-lactamase-producing plasmids were determined as class 1 integron sequence, of 3 harbored 2 drug resistance gene cassettes encoding resistance to aminoglycosides(aacA4 and aadA5), trimethoprin (dfrA17)and chloramphenicol (cmlA4). Conclusion More attention should be paid to integron which plays an important role in multi-resistance from plasmid-mediated AmpC beta-lactamase.