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Microwaves in Lactam Chemistry
Published in Banik Bimal Krishna, Bandyopadhyay Debasish, Advances in Microwave Chemistry, 2018
Dr. Debasish Bandyopadhyay, Bimal Krishna Banik
Microwave-assisted synthesis of the compounds (66a–67d) was carried out through 1,3-dipolar cycloaddition of isatin, 1,3-thiazole-4-carboxylic acid, and a Knoevenagel adduct in 2,2,2-trifluoroethanol as a green solvent. All four compounds demonstrated high antibacterial activity against Klebsiella pneumonia with MIC value ranging from 0.005 to 0.19 µg/mL. In addition, the compound 67c exhibited in silico drugability against the protein New Delhi Metallo-beta-Lactamase-1 (NDM-1; PDB ID: 4HL2) [107].
Introduction to graph theory
Published in Karthik Raman, An Introduction to Computational Systems Biology, 2021
Create the network corresponding to Cα atoms in the structure of the enzyme NDM-1 (New Delhi metallo-β-lactamase), which is used by bacteria to inactivate a wide range of penicillin-like antibiotics (PDB ID: 4eyl), using the NAPS portal (§2.5.3). How many edges are there in the network? Can you see how the different networks generated based on interaction strength, or Cβ atoms differ from one another in their density?
β-Lactams and Related Compounds as Antibacterials and β-Lactamase Inhibitors
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2020
Ulrike Holzgrabe, Jens Schmitz
Class B metallolactamases (MBLs) are a divergent class with low sequence similarity within the class. They are not homologous to transpeptidases and more or less structurally unrelated to serine-β-lactamases. They are featuring the distinct αβ/βα fold of the metallo-hydrolase/oxidoreductase (Mojica et al., 2016) and form three subclasses B1-B3 based on the sequence similarity and metal site occupancy. The B1 MBL subclass consists of imipenemase (IMP), first reported in 1991 and containing over 50 variants, the Verona integron-coded MBL (VIM), described in 1999, and the New Delhi Metallo-β-lactamase (NDM-1), being the clinically most important and dangerous ones (Rotondo and Wright, 2017). From phylogeny studies, it was hypothesized that subclass B1 and B2 evolved 1 billion year ago, and B3 before Gram-positive and Gram-negative bacteria have been diverted (Hall et al., 2004). The reactions mechanisms were intensively studied by Abboud et al. (2017) and (2018) by protein-observed 19F NMR spectroscopy. They are able to destroy the last line β-lactam carbapenems and they are often found in P aeruginosa and E. coli. Unfortunately, their genes are located on mobile genetic elements, which can cause an extremely fast distribution of resistant bacteria throughout the world as was seen with the outbreak of the NDM-1 pathogen in 2009. NDM-1 can be regarded as a super bug, hydrolyzing all (!) β-lactams except aztreonam (Khan et al., 2017). Source organisms of the different variants of NDM-1 which are formed meanwhile and which are at least 20, are currently E. coli, A. baumannii, and Klebsiella pneumoniae. It is alarming because not only a very few antibiotics are active against those resistant bacteria but also inhibitors against them are not available (see below). Unfortunately, the first generation of β-lactamases inhibitors BLIs does not hit the class B lactamases.
Structural effects of nanoparticles on their antibacterial activity against multi-drug resistance
Published in Inorganic and Nano-Metal Chemistry, 2022
Bharti Goyal, Neelam Verma, Tannu Kharewal, Anjum Gahlaut, Vikas Hooda
Over the recent years, the bacterial community has developed antibiotic-resistant strains (mainly MDR strains) that can confront the given mode of action of antibiotics. They have accomplished various resistance strategies. These include—the expression of genes that promote the efflux of antibiotics,[3] the synthesis of an enzyme that can degrade or alter antimicrobial agents,[4] modification of cellular components such as cell walls, ribosomes.[5] Clinically, due to misuse of antibiotics, “superbugs” have been reported which are almost resistant to all antibiotics.[3] They are supposed to contain a gene named—New Delhi Metallo-beta-lactamase 1 (NDM-1).[6] Most of the bacteria aggregate by extracellular polymeric substance (EPS) and form biofilm. It acts as a fence and blocks the entry of antibiotics, offers a basis for prolonged infections.
Emergence of carbapenem resistant Acinetobacter baumannii clonal complexes CC2 and CC10 among fecal carriages in an educational hospital
Published in International Journal of Environmental Health Research, 2021
Mohsen Nazari, Omid Azizi, Hamid Solgi, Sepideh Fereshteh, Shervin Shokouhi, Farzad Badmasti
Our findings indicate that successful clones CC2 and CC10 which recovered from fecal carriage showed a high carbapenem resistance and harbored blaVIM, blaOXA-23, and blaIMP genes. Maybe the human gut microbiota, allow the horizontal transfer of genetic material, including antibiotic resistance genes. Resistance gene transfer from commensals to gut-dwelling opportunistic pathogens can be happening and may contribute to the emergence of MDR strains (Huddleston 2014). There are a few studies that address the A. baumannii fecal carriage in clinical settings. One study indicated that 8.3% (47/565) of fecal isolates were A. baumannii, and 6.2% (35/565) were resistant to carbapenem (Aljindan et al. 2015). Moreover, the blaNDM-1 gene was identified in up to 77% of the carbapenem-resistant Acinetobacter isolated from fecal survey samples in the clinical setting, indicating that the gut might be a reservoir of resistant bacteria (Li et al. 2019). It seems that the intestinal opportunistic bacteria that can be transmitted through the fecal-hand is a clinical threat to the development of nosocomial infection.
Understanding human health risks caused by antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) in water environments: Current knowledge and questions to be answered
Published in Critical Reviews in Environmental Science and Technology, 2020
Mohan Amarasiri, Daisuke Sano, Satoru Suzuki
In the transduction process, cellular DNA packaged to the bacteriophages during their replication will be incorporated to the host bacterial genome after the infection by a transduced bacteriophage (Calero-Cáceres, Ye, & Balcázar, 2019). Extended spectrum beta-lactamase (ESBL) genes blaTEM, blaCTX-M, blaCMY-2, blaKPC,blaOXA-48,blaPSE, conferring resistance to β-lactam antibiotics were detected in DNA of bacteriophages isolated from canal water, urban sewage and river water samples collected from Washington State whereas blaNDM-1 gene was detected from bacteriophage DNA fraction isolated from river and wastewater samples (A. Zhang et al., 2019). Analysis of viromes from seven marine habitats including Arctic Ocean, Indian Ocean and Gulf of Mexico confirmed the presence of phage associated ARGs (Calero-Cáceres & Balcázar, 2019). Muniesa et al. (2013) have provided a detailed review on the contribution of environmental bacteriophages on spreading ARGs (Muniesa, Colomer-Lluch, & Jofre, 2013b).