Analysis on distribution and characterization of drug-resistant determinants in clinical bacteria

  Objective   To investigate the distribution and characterization of integrons in clinical strains.

  Methods   The presence and genetic content of 3 classes integrons among 55 clinical strains were examined by multiple PCR and sequencing.

  Results   55 (100%)strains were positive for intI1 gene.Furthermore, intI1-positive strains were amplified with primers of in-F and in-B which were set for amplifying the region of antibiotics resistance genes.Among 55 strains, an amplicon of 1 913 bp was yielded in 49 isolates, an amplicon of 1 664 bp was yielded in 6 isolates.Sequencing analysis revealed that amplicon 1 913 bp harbored genes of dhfr, orfF and aadA 2, amplicon 1 664 bp harbored genes of aadA5 and dfr 17, adA 2 and aadA 5 showing aminoglycoside resistance; dhfr and dfr 17 conferring resistance to trimethoprim, orfF encoding unknown function.

  Conclusion   Resistance gene(s)mediated by class 1 integron was extensively existed in clinical isolates of both gram-negative and gram-positive bacteria.The result stressed the need for continued surveillance of antibiotic resistance gene(s)horizontal transference among bacteria genus.