Co-existence of bla_IMP, bla_NDM-1, and bla_SHV, genes of Pseudomonas aeruginosa isolated from Quetta: Antimicrobial resistance and clinical significance

Objective: Molecular detection and co-presence of carbapenem-resistant genes in the isolates of Pseudomonas aeruginosa are less commonly reported from Quetta. In the present study, we determined to highlight the antibiotic sensitivity profile and genetic mechanism of carbapenem resistance.

Methods: The cross-sectional study was conducted from May to September 2018 at the Hi-tech laboratory, Centre for Advance Studies in Vaccinology and Biotechnology, University of Baluchistan, Quetta. Biochemical and molecular methods were ascertained for the recognition of the isolates and minimum inhibitory concentration was performed using E-test and broth microdilution methods. The molecular basis of carbapenemase activity was determined by identifying carbapenemase genes in the isolates.

Results: Of the (n=23) P. aeruginosa isolated from pus aspirates obtained from surgical/burn units, we have detected bla_IMP (n=7/8) 87.5%, bla_NDM-1 (n=5/8) 62.5%, and bla_SHV (n=4/8) 50%. The co-existence of multiple antibiotic-resistant genes, bla_IMP, bla_NDM-1 and bla_SHV was found in (n=2/8) 25% isolates. These isolates displayed resistance against a range of antimicrobials from β-lactams, tetracyclines, cephalosporins, quinolones, monobactams, aminoglycosides, sulphonamides, phosphoric acid, macrolides, and polypeptide groups, suggesting extensive-drug resistance.

Conclusion: The emergence of MBL and ESBL producers is an alarming threat in the region. It is of great importance to determine the resistance mechanism of bacterial bugs. The lack of new antimicrobials particularly against gram-negative bacteria is quite alarming worldwide.