A Comparative Study of KPC-, VIM-, NDM- and IMP-Type Carbapenemase Genes in Clinical and Environmental Isolates of Pseudomonas aeruginosa Using Similar Protocol in Real-Time PCR Method

Production of Carbapenemase enzymes in Pseudomonas aeruginosa isolated from clinic, has challenged the treatment of these infections and due to its natural habitat in soil and aquatic environments. This study aimed to compare carbapenemase resistance genes (VIM, KPC, NDM and IMP) using similar protocol for the four above-mentioned genes in clinical and enviromemtal isolates by Real-Time PCR.

  The clinical isolates were isolated from two Tabriz Hospitals and environmental isolates from Nahnad and Spiran rivers. For their genotypic idententification we used universal primer of 16s rRNA. They were investigated for Carbapenemase production via phenotypic disk agar diffusion and combined disk methods and then Real-Time PCR was conducted using specific primers for the above-mentioned genes.

By phenotypic methods, 83.3 percent of clinical and 0% of environmental isolates were Carbapenemase producers. However. both clinical and environmental isolates showed blaNDM-1, blaIMP, blaKPC and blaVIM genes by Real-Time PCR.

This study showed that the carbapenemase enzymes’ genes in clinical and environmental isolates were checked for four KPC, VIM, NDM and IMP genes by similar protocol and the presence of above genes in environmental isolates. Furthermore, clinical ones revealed the possibility of bacteria spreading as a superbug increasingly.