Loop-mediated isothermal amplification assay versus polymerase chain reaction for detection of blaNDM-1 and blaKPC genes among Gram negative isolates

Abstract

Background: New Delhi Metallo-b-lactamase (NDM- 1) and Klebsiella pneumoniae carbapenemase (KPC) are enzymes associated with resistance to many β- lactam agents. Their early detection is very important for controlling the spread of drug- resistant bacteria. This study aimed to evaluate the use of LOOP-mediated isothermal amplification technique (LAMP) assay for rapid and cost-effective detection of blaNDM-1 and blaKPC genes among Gram-negative bacteria in comparison with conventional PCR. Methods: A total of 156 gram-negative bacterial isolates [Escherichia coli (43), Klebsiella spp. (66), Pseudomonas spp. (47)] were screened for the presence of carbapenemases (blaNDM-1 and blaKPC) using molecular methods such as conventional PCR and LAMP assay. Results: blaNDM1 was positive in 94/156 (60.2%) isolates and blaKPC was positive in 37/156 (23.7%) isolates by conventional PCR and LAMP. Conclusion: The LAMP technique is an excellent option for the rapid detection of blaNDM-1 and blaKPC genes. The amplification is faster and cheaper than other molecular techniques. It is easy to implement. The thermocycler is not necessary.