Phenotypic and genotypic detection of the production of carbapenemases type NDM-1 and KPC in isolated enterobacteriaceae in a clinical laboratory in Maracay, Venezuela

Abstract

Background: The production of carbapenem-hydrolyzing b-lactamases is one of the most concerning resistance mechanisms since it eliminates the last therapeutic option against multidrug resistant microorganisms. Aim: To determine the production of KPC and NDM-1 type carbapenemases, using phenotypic and genotypic methods, in isolated enterobacteria in a clinical laboratory in the city of Maracay, Venezuela. Methods: The production of carbapenemases was determined by phenotypic (according to the Malbrán algorithm) and genotypic methods (amplification of the bla_NDM-1 and bla_KPC genes by PCR) in clinical isolates of Enterobacteriaceae during the period march-august 2018. Results: 605 Enterobacteriaceae of different species were identified, being Escherichia coli the strain with the highest percentage of isolation (61.3%), followed by Klebsiella pneumoniae (14.9%). Sixteen strains (2.64%) were positive for carbapenemases production: 13 strains of K. pneumoniae and three of the Enterobacter cloacae complex. PCR showed that 14 strains (87.5%) carry the bla_NDM-1 gene and two strains (12.5%) the bla_KPC gene; 100% agreement was observed between phenotypic determination and PCR for both groups of enzymes. Conclusions: The results of this study showed a higher incidence of metallo-b-lactamase type NDM-1, which rapid dissemination and consequently difficult control has been cause of epidemiological alert. The identification of the type of enzyme would allow establishing more accurate management and control strategies in order to eradicate these pathogens.