NDM Metallo-β-Lactamases and Their Bacterial Producers in Health Care Settings

Abstract

SUMMARYNew Delhi metallo-β-lactamase (NDM) is a metallo-β-lactamase able to hydrolyze almost all β-lactams. Twenty-four NDM variants have been identified in >60 species of 11 bacterial families, and several variants have enhanced carbapenemase activity.Klebsiella pneumoniaeandEscherichia coliare the predominant carriers ofblaNDM, with certain sequence types (STs) (forK. pneumoniae, ST11, ST14, ST15, or ST147; forE. coli, ST167, ST410, or ST617) being the most prevalent. NDM-positive strains have been identified worldwide, with the highest prevalence in the Indian subcontinent, the Middle East, and the Balkans. MostblaNDM-carrying plasmids belong to limited replicon types (IncX3, IncFII, or IncC). Commonly used phenotypic tests cannot specifically identify NDM. Lateral flow immunoassays specifically detect NDM, and molecular approaches remain the reference methods for detectingblaNDM. Polymyxins combined with other agents remain the mainstream options of antimicrobial treatment. Compounds able to inhibit NDM have been found, but none have been approved for clinical use. Outbreaks caused by NDM-positive strains have been reported worldwide, attributable to sources such as contaminated devices. Evidence-based guidelines on prevention and control of carbapenem-resistant Gram-negative bacteria are available, although none are specific for NDM-positive strains. NDM will remain a severe challenge in health care settings, and more studies on appropriate countermeasures are required.

Real-time sampling of travelers shows intestinal colonization by multidrug-resistant bacteria to be a dynamic process with multiple transient acquisitions

“…We screened for ESBL-producing strains, but carbapenemase producers would also have grown on the selective plates used. However, WGS analysis showed a complete absence of carbapenemase genes, a finding somewhat surprising in Southeast Asia where the prevalence of carbapenem-resistant Enterobacteriaceae is increasing [34]. Such isolates have only recently been reported in Laos [35], suggesting that carbapenem resistance has not yet become a major problem in the country.…”

<p>Emergence of Almost Identical F36:A-:B32 Plasmids Carrying <em>bla</em>_NDM-5 and <em>qepA</em> in <em>Escherichia coli </em>from Both Pakistan and Canada</p>

“…5 NDM is able to hydrolyze almost all βlactams, and the hydrolytic activity of NDM enzymes cannot be weakened by βlactamase inhibitors, such as clavulanate, tazobactam, sulbactam, and avibactam, leaving limited therapeutic options for infections caused by NDM-producing Enterobacteriaceae. 6 bla NDM genes are usually located on plasmids capable of efficient transfer between bacterial species and hosts in and out of hospitals. 3 Though carbapenems are not legally prescribed for use in livestock production, the occurrence of carbapenemresistant Enterobacteriaceae (CRE), especially NDMproducing Enterobacteriaceae has been increasingly reported in livestock and meat products in the world.…”

Coexistence of the blaNDM-1-carrying plasmid pWLK-NDM and the blaKPC-2-carrying plasmid pWLK-KPC in a Raoultella ornithinolytica isolate

“…The bla NDM genes have so far been found to be present in multiple species 27 . Plasmids with a variety of replicon types, including IncA/C, IncF, IncH, IncN, IncL/M, IncP, IncR, IncX, and IncY, as well as untypeable plasmids have been identified to be the carriers of the bla NDM genes 27 . In China, the bla NDM-1 gene was first identified in Acinetobacter baumannii isolates and found to be carried mainly by Acinetobacter spp.…”