These are involved in acquired resistance and belong to Ambler molecular classes A, B and D. Carbapenemases may be defined as specific beta-lactamases, which hydrolyze carbapenem group of antibiotics. In Enterobacteriaceae and other Gram-negative bacteria including Pseudomonas and Acinetobacter species, production of carbapenemases has become a noteworthy mechanism for broad-spectrum β-lactam resistance. Recent reports on antibiotic resistance has made a clear understanding of evolving status of β-lactamase enzymes, which are key player for antibiotic resistance. The activity of an enzyme and its future generations success in response to change conditions due to environmental stress and its improved physiological utility for constant perseverance is determined by these evolutionary drivers. The overuse of antibiotics is one of the reasons to cause resistance, due to increase selective pressure in a specific population of bacteria allowing the resistant bacteria to bloom and the susceptible bacteria to pass away.Įnzymes are evolving over a period of time by mutations in response to environmental pressure for increased stability and fitness leading to its functional changes. The possible reason for evolving trends of new markers is mutations, which may cause delaying in the discovery of new antibiotics for treatments and hence became a great public threat. This review provides a comprehensive view of structural differences among NDM-1 variants, which are a driving force behind their spread across the globe.Īlthough antibiotics were developed to fight infections, the emergence of new resistant markers, especially New Delhi-metallo-beta-lactamases (NDM-1), hampered the capability of all antibiotics of beta lactam group to treat infections caused by microorganisms carrying such resistances. The genetic and structural studies of these variants are important to understand the mechanism of antibiotic hydrolysis as well as to design new molecules with inhibitory activity against antibiotics. Moreover, at least seventeen variants of bla NDM-type gene differing into one or two residues of amino acids at distinct positions have been reported so far among different species of bacteria from different countries.

and Acinetobacter baumannii were found to carry these markers. Wide members of enterobacteriaceae, most commonly Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and gram-negative non-fermenters Pseudomonas spp. In this review, we have discussed bla NDM-1variants, its genetic analysis including type of specific mutation, origin of country and spread among several type of bacterial species. NDM-1 hydrolyzes a wide range of β-lactam antibiotics, including carbapenems, which are the last resort of antibiotics for the treatment of infections caused by resistant strain of bacteria. The emergence of carbapenemase producing bacteria, especially New Delhi metallo-β-lactamase (NDM-1) and its variants, worldwide, has raised amajor public health concern.

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