Genetic Characterization of Plasmids Carrying Carbapenemases and Quinolone Resistance Determinants in Klebsiella Pneumoniae Isolates in Assiut University Hospitals

Plasmid mediated carbapenem resistance is mainly due to production of carbapenemase which belong to three classes of β-lactamases, the Ambler class A, B and D β -lactamases, among which the New Delhi metallo-β -lactamase has attracted significant attention in the last five years. New Delhi metallo-β -lactamase-1 is a class B metallo-β-lactamase and was first identified from a Klebsiella pneumoniae strain in 2008.

New Delhi metallo-β -lactamase-1 is frequently associated with other resistance genes, such as extended spectrum β- lactamase genes and plasmid-mediated quinolone resistance genes, which allows bacteria to gain resistance to different classes of antimicrobial agents simultaneously.

Plasmids and Integrons are mobile genetic elements that carry antimicrobial resistance genes. Horizontal transfer of those mobile genetic elements has been considered as one of the most important mechanisms for the dissemination of multi-drug resistance among bacteria.

Classification of plasmids on the basis of molecular typing and phylogenetic relatedness may help understand the distribution of plasmid types, the relationships involving plasmids carrying antimicrobial resistance genes. Plasmids can be classified into incompatibility groups by replicon typing or into types (clusters) by restriction fragment length polymorphism analysis.

Integrons act as genetic platform, which allow capture and expression of antibiotic resistance genes. There are 3 classes of integrons that are responsible for multi-drug resistance, which are classified based on the sequence of the integrase gene. Class 1 integrons are the most widespread class in Gram-negative bacteria.