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Artigos de revistas sobre o tema "Lactams"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 25 de julho de 2025

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1

Li, Lu, Qiyao Wang, Hui Zhang, Minjun Yang, Mazhar I. Khan та Xiaohui Zhou. "Sensor histidine kinase is a β-lactam receptor and induces resistance to β-lactam antibiotics". Proceedings of the National Academy of Sciences 113, № 6 (2016): 1648–53. http://dx.doi.org/10.1073/pnas.1520300113.

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β-Lactams disrupt bacterial cell wall synthesis, and these agents are the most widely used antibiotics. One of the principle mechanisms by which bacteria resist the action of β-lactams is by producing β-lactamases, enzymes that degrade β-lactams. In Gram-negative bacteria, production of β-lactamases is often induced in response to the antibiotic-associated damage to the cell wall. Here, we have identified a previously unidentified mechanism that governs β-lactamase production. In the Gram-negative enteric pathogenVibrio parahaemolyticus, we found a histidine kinase/response regulator pair (Vbr

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2

Medina, Marjorie B., Dana J. Poole та M. Ranae Anderson. "A Screening Method for β-Lactams in Tissues Hydrolyzed with Penicillinase I and Lactamase II". Journal of AOAC INTERNATIONAL 81, № 5 (1998): 963–72. http://dx.doi.org/10.1093/jaoac/81.5.963.

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Abstract Antibiotic residues above tolerance levels are not allowed in foods derived from farm animals. Microbial inhibition assays are used to screen antibiotics in U.S. regulatory laboratories. We developed a screening approach to classify β-lactams through selective hydrolysis of the β-lactam ring with Penase™ or lactamase II, thereby inactivating the β- lactam activity. Optimum conditions for hydrolysis of β-lactams with Penase and lactamase II were determined. p-Lactams were detected by a microbial inhibition assay and with enzyme-linked immunosorbent assays before and after hydrolysis. β

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3

Alves, Américo J. S., Nuno G. Alves, Cátia C. Caratão, et al. "Spiro-Lactams as Novel Antimicrobial Agents." Current Topics in Medicinal Chemistry 20, no. 2 (2020): 140–52. http://dx.doi.org/10.2174/1568026619666191105110049.

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Introduction: Structural modulation of previously identified lead spiro-β-lactams with antimicrobial activity was carried out. Objective: The main objective of this work was to synthesize and evaluate the biological activity of novel spiro-lactams based on previously identified lead compounds with antimicrobial activity. Methods: The target chiral spiro-γ-lactams were synthesized through 1,3-dipolar cycloaddition reaction of a diazo-γ-lactam with electron-deficient dipolarophiles. In vitro activity against HIV and Plasmodium of a wide range of spiro-β-lactams and spiro-γ-lactams was evaluated.

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Li, Xian-Zhi, Li Zhang, Ramakrishnan Srikumar та Keith Poole. "β-Lactamase Inhibitors Are Substrates for the Multidrug Efflux Pumps of Pseudomonas aeruginosa". Antimicrobial Agents and Chemotherapy 42, № 2 (1998): 399–403. http://dx.doi.org/10.1128/aac.42.2.399.

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ABSTRACT The MexAB-OprM multidrug efflux system exports a number of antimicrobial compounds, including β-lactams. In an attempt to define more fully the range of antimicrobial compounds exported by this system, and, in particular, to determine whether β-lactamase inhibitors were also accommodated by the MexAB-OprM pump, the influence of pump status (its presence or absence) on the intrinsic antibacterial activities of these compounds and on their abilities to enhance β-lactam susceptibility in intact cells was assessed. MIC determinations clearly demonstrated that all three compounds tested, c

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5

Brilhante, R. S. N., L. G. A. Valente, M. F. G. Rocha та ін. "Sesquiterpene Farnesol Contributes to Increased Susceptibility to β-Lactams in Strains of Burkholderia pseudomallei". Antimicrobial Agents and Chemotherapy 56, № 4 (2012): 2198–200. http://dx.doi.org/10.1128/aac.05885-11.

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ABSTRACTThis study aimed to evaluate thein vitrocombination of farnesol and β-lactams againstBurkholderia pseudomallei. A total of 12 β-lactamase-positive strains were tested according to CLSI standards. All strains were inhibited by farnesol, with MICs ranging from 75 to 150 μM. The combination of this compound with β-lactams resulted in statistically significant β-lactam MIC reduction (P≤ 0.05). This study provides new perspectives for the use of farnesol combined with β-lactam antibiotics against strains ofB. pseudomallei.

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6

Jacobs, Lian M. C., Patrick Consol та Yu Chen. "Drug Discovery in the Field of β-Lactams: An Academic Perspective". Antibiotics 13, № 1 (2024): 59. http://dx.doi.org/10.3390/antibiotics13010059.

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β-Lactams are the most widely prescribed class of antibiotics that inhibit penicillin-binding proteins (PBPs), particularly transpeptidases that function in peptidoglycan synthesis. A major mechanism of antibiotic resistance is the production of β-lactamase enzymes, which are capable of hydrolyzing β-lactam antibiotics. There have been many efforts to counter increasing bacterial resistance against β-lactams. These studies have mainly focused on three areas: discovering novel inhibitors against β-lactamases, developing new β-lactams less susceptible to existing resistance mechanisms, and ident

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Sekiguchi, Jun-ichiro, Koji Morita, Tomoe Kitao та ін. "KHM-1, a Novel Plasmid-Mediated Metallo-β-Lactamase from a Citrobacter freundii Clinical Isolate". Antimicrobial Agents and Chemotherapy 52, № 11 (2008): 4194–97. http://dx.doi.org/10.1128/aac.01337-07.

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ABSTRACT A novel gene, bla KHM-1, encoding a metallo-β-lactamase, KHM-1, was cloned from a clinical isolate of Citrobacter freundii resistant to most β-lactam antibiotics. Escherichia coli expressing bla KHM-1 was resistant to all broad-spectrum β-lactams except for monobactams and showed reduced susceptibility to carbapenems. Recombinant KHM-1 exhibited EDTA-inhibitable hydrolytic activity against most β-lactams, with an overall preference for cephalosporins.

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8

Glen, Karl A., та Iain L. Lamont. "β-lactam Resistance in Pseudomonas aeruginosa: Current Status, Future Prospects". Pathogens 10, № 12 (2021): 1638. http://dx.doi.org/10.3390/pathogens10121638.

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Pseudomonas aeruginosa is a major opportunistic pathogen, causing a wide range of acute and chronic infections. β-lactam antibiotics including penicillins, carbapenems, monobactams, and cephalosporins play a key role in the treatment of P. aeruginosa infections. However, a significant number of isolates of these bacteria are resistant to β-lactams, complicating treatment of infections and leading to worse outcomes for patients. In this review, we summarize studies demonstrating the health and economic impacts associated with β-lactam-resistant P. aeruginosa. We then describe how β-lactams bind

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9

Mukhopadhyay, S., and P. Chakrabarti. "Altered permeability and beta-lactam resistance in a mutant of Mycobacterium smegmatis." Antimicrobial Agents and Chemotherapy 41, no. 8 (1997): 1721–24. http://dx.doi.org/10.1128/aac.41.8.1721.

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Beta-lactam resistance in mycobacteria results from an interplay between the following: (i) beta-lactamase production, (ii) affinity of the penicillin-binding proteins (PBPs) for the drugs, and (iii) permeation of the drugs. A laboratory mutant of Mycobacterium smegmatis was studied in order to evaluate the roles of these factors in beta-lactam resistance. Mutant M13 was between 7- and 78-fold more resistant than the wild type to cephaloridine, cefoxitin, cefazolin, cefamandole, and cephalothin. Increased beta-lactamase activity toward these antibiotics was not observed in the mutant. The PBP

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10

Li, Fu, Li Wan, Tongyang Xiao та ін. "In Vitro Activity of β-Lactams in Combination with β-Lactamase Inhibitors against Mycobacterium tuberculosis Clinical Isolates". BioMed Research International 2018 (2 липня 2018): 1–8. http://dx.doi.org/10.1155/2018/3579832.

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Objectives. Evaluating the activity of nineteen β-lactams in combination with different β-lactamase inhibitors to determine the most potent combination against Mycobacterium tuberculosis (MTB) in vitro. Methods. Drug activity was examined by drug susceptibility test with 122 clinical isolates from China. Mutations of blaC and drug targets ldtMt1, ldtMt2, dacB2, and crfA were analyzed by nucleotide sequencing. Results. Tebipenem (TBM) in combination with clavulanate (CLA) exhibited the highest anti-TB activity. The MIC of β-lactam antibiotics was reduced most evidently in the presence of CLA, c

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Yin, Jianhua, Yiyang Sun, Yinting Mao, Miao Jin та Haichun Gao. "PBP1a/LpoA but Not PBP1b/LpoB Are Involved in Regulation of the Major β-Lactamase GeneblaAin Shewanella oneidensis". Antimicrobial Agents and Chemotherapy 59, № 6 (2015): 3357–64. http://dx.doi.org/10.1128/aac.04669-14.

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ABSTRACTβ-Lactamase production is one of the most important strategies for Gram-negative bacteria to combat β-lactam antibiotics. Studies of the regulation of β-lactamase expression have largely been focused on the class C β-lactamase AmpC, whose induction by β-lactams requires LysR-type regulator AmpR and permease AmpG-dependent peptidoglycan recycling intermediates. InShewanella, which is ubiquitous in aquatic environments and is a reservoir for antibiotic resistance, production of the class D β-lactamase BlaA confers bacteria with natural resistance to many β-lactams. Expression of theblaAg

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Asgarali, Azizah, Keith A. Stubbs, Antonio Oliver, David J. Vocadlo та Brian L. Mark. "Inactivation of the Glycoside Hydrolase NagZ Attenuates Antipseudomonal β-Lactam Resistance in Pseudomonas aeruginosa". Antimicrobial Agents and Chemotherapy 53, № 6 (2009): 2274–82. http://dx.doi.org/10.1128/aac.01617-08.

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ABSTRACT The overproduction of chromosomal AmpC β-lactamase poses a serious challenge to the successful treatment of Pseudomonas aeruginosa infections with β-lactam antibiotics. The induction of ampC expression by β-lactams is mediated by the disruption of peptidoglycan (PG) recycling and the accumulation of cytosolic 1,6-anhydro-N-acetylmuramyl peptides, catabolites of PG recycling that are generated by an N-acetyl-β-d-glucosaminidase encoded by nagZ (PA3005). In the absence of β-lactams, ampC expression is repressed by three AmpD amidases encoded by ampD, ampDh2, and ampDh3, which act to deg

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13

Sayed, Alaa R. M., Nirav R. Shah, Kari B. Basso та ін. "First Penicillin-Binding Protein Occupancy Patterns for 15 β-Lactams and β-Lactamase Inhibitors in Mycobacterium abscessus". Antimicrobial Agents and Chemotherapy 65, № 1 (2020): e01956-20. http://dx.doi.org/10.1128/aac.01956-20.

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ABSTRACTMycobacterium abscessus causes serious infections that often require over 18 months of antibiotic combination therapy. There is no standard regimen for the treatment of M. abscessus infections, and the multitude of combinations that have been used clinically have had low success rates and high rates of toxicities. With β-lactam antibiotics being safe, double β-lactam and β-lactam/β-lactamase inhibitor combinations are of interest for improving the treatment of M. abscessus infections and minimizing toxicity. However, a mechanistic approach for building these combinations is lacking sin

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14

Nagira, Yu, Keiko Yamada, Hayato Okade та ін. "1279. In Vitro Activity of Nacubactam (OP0595) Alone and in Combination with β-Lactams against β-Lactamase-Producing Enterobacterales Isolated in Japan". Open Forum Infectious Diseases 7, Supplement_1 (2020): S655. http://dx.doi.org/10.1093/ofid/ofaa439.1462.

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Abstract Background Nacubactam (NAC) is a novel serine β-lactamase inhibitor in clinical development, and inhibits Ambler class A, class C, and some class D β-lactamases. In addition, it has penicillin-binding protein (PBP) 2-dependent antibacterial activity and an ‘enhancer’ effect when combined with β-lactams bound to PBP3. This study assessed the in vitro activity of NAC alone and in combination with β-lactams against IMP-type metallo-β-lactamase-producing and ESBL-producing Enterobacterales isolated in Japan. Methods The MICs for the clinical isolates in Japan were determined and time kill

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15

Yuan, Qinghui, Lin He та Hengming Ke. "A Potential Substrate Binding Conformation of β-Lactams and Insight into the Broad Spectrum of NDM-1 Activity". Antimicrobial Agents and Chemotherapy 56, № 10 (2012): 5157–63. http://dx.doi.org/10.1128/aac.05896-11.

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ABSTRACTNew Delhi metallo-β-lactamase 1 (NDM-1) is a key enzyme that the pathogenKlebsiella pneumoniauses to hydrolyze almost all β-lactam antibiotics. It is currently unclear why NDM-1 has a broad spectrum of activity. Docking of the representatives of the β-lactam families into the active site of NDM-1 is reported here. All the β-lactams naturally fit the NDM-1 pocket, implying that NDM-1 can accommodate the substrates without dramatic conformation changes. The docking reveals two major binding modes of the β-lactams, which we tentatively name the S (substrate) and I (inhibitor) conformers.

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Papp-Wallace, Krisztina M., Baui Senkfor, Julian Gatta та ін. "Early Insights into the Interactions of Different β-Lactam Antibiotics and β-Lactamase Inhibitors against Soluble Forms of Acinetobacter baumannii PBP1a and Acinetobacter sp. PBP3". Antimicrobial Agents and Chemotherapy 56, № 11 (2012): 5687–92. http://dx.doi.org/10.1128/aac.01027-12.

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ABSTRACTAcinetobacter baumanniiis an increasingly problematic pathogen in United States hospitals. Antibiotics that can treatA. baumanniiare becoming more limited. Little is known about the contributions of penicillin binding proteins (PBPs), the target of β-lactam antibiotics, to β-lactam–sulbactam susceptibility and β-lactam resistance inA. baumannii. Decreased expression of PBPs as well as loss of binding of β-lactams to PBPs was previously shown to promote β-lactam resistance inA. baumannii. Using anin vitroassay with a reporter β-lactam, Bocillin, we determined that the 50% inhibitory con

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17

Tarui, Atsushi, Yukiko Karuo, Kazuyuki Sato, Kentaro Kawai та Masaaki Omote. "Stereoselective Synthesis of Multisubstituted α-fluoro-β-lactams". Current Organic Chemistry 24, № 18 (2020): 2169–80. http://dx.doi.org/10.2174/1385272824666200221114707.

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β-Lactams, found in β -lactam antibiotics, are the structurally distorted cyclic compounds being subjected to nucleophilic acyl substitution reaction. α-Fluorination of β -lactams is a simple and expedient approach to control the reactivity of β-lactam ring toward nucleophilic attack, which would hopefully lead to the new design of future antibiotics. From the viewpoint of obtaining multisubstituted α -fluoro-β-lactams, α -bromo-α- fluoro-β-lactams are considered as key compounds for structure functionalization, including nucleophilic substitution reaction, aldol-type reaction and metal-cataly

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18

Srivastava, Nitin. "Key Role of Ionic Liquids in the Cleaner and Greener Synthesis of Lactams." Research Journal of Chemistry and Environment 26, no. 1 (2021): 125–30. http://dx.doi.org/10.25303/2601rjce125130.

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The antibiotics like cephalosporin, penicillin etc. contain lactams as the main component. Due to increase in bacterial resistance to antibiotics, there is a need of synthesis of novel β-lactam agents that are stable to β-lactamase and have high potency on broad spectrum. Besides this β-lactams also decrease the cholesterol in blood plasma. They are potent anticancer agents and enzyme inhibiting substances. Ionic liquids have been found to be versatile greener solvents employed for the synthesis of lactams with many other advantages in comparison to traditional media. They are said to be “tail

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Gangadharappa, Bhavya, Manjunath Dammalli та Sharath Rajashekarappa. "β-Lactams and β-Lactamase Inhibitors: Unlocking their potential to address drug resistance". Research Journal of Biotechnology 16, № 8 (2021): 151–58. http://dx.doi.org/10.25303/168rjbt15121.

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Antibiotics such as β-lactams are one of the most widely used antibacterial drug classes in the world. The invention of the first β-lactam antibiotic (Penicillin) is regarded as a symbolic landmark in the history of modern chemotherapy. Since that time, several other β-lactam antibiotics have been added to the treatment, revolutionising the treatment of bacterial infections. Antibacterial efficacy of the β-lactams has been kept in check by the emergence of bacterial resistance. One of the most studied and common resistance mechanisms is the expression of β-lactamase enzymes. The invention of β

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Patel, Twisha S., Vince Marshall, Keith S. Kaye та ін. "1600. Susceptibility of β-Lactam-Resistant Pseudomonas aeruginosa to Other β-Lactams: Is There Truly a Lack of Cross-Resistance?" Open Forum Infectious Diseases 6, Supplement_2 (2019): S583—S584. http://dx.doi.org/10.1093/ofid/ofz360.1464.

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Abstract Background Resistance to β-lactams in P. aeruginosa is complex with multiple mechanisms contributing. Since different mechanisms impact different β-lactams to differing degrees, a common dogma is that resistance to one β-lactam does not lead to resistance to others. The purpose of this analysis was to assess the frequency of β-lactam cross-resistance in P. aeruginosa. Methods Unique P. aeruginosa isolated in 2017 at Michigan Medicine were included. Overall, susceptibility (using CLSI breakpoints) and MIC distributions of β-lactams were assessed in all isolates and those with β-lactam

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Nagpal, Reshma, Jitender Bhalla та Shamsher S. Bari. "A Comprehensive Review on C-3 Functionalization of β-Lactams". Current Organic Synthesis 16, № 1 (2019): 3–16. http://dx.doi.org/10.2174/1570179415666181116103341.

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Background:A lot of advancement has been made in the area of β-lactams in recent times. Most of the research is targeted towards the synthesis of novel β-lactams, their functionalization and exploring their biological potential. The C-3 functionalization of β-lactams has continued to attract considerable interest of the scientific community due to their utility as versatile intermediates in organic synthesis and their therapeutic applications. This has led to the significant increase in efforts towards developing efficient and economic strategies for C-3 functionalized β-lactams.Objective:The

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Dousa, Khalid M., Barry N. Kreiswirth, Sebastian Kurz, and Robert A. Bonomo. "786. Ceftaroline and Avibactam? Is This a Potential Combination for Mycobacterium abscessus Infection?" Open Forum Infectious Diseases 5, suppl_1 (2018): S281. http://dx.doi.org/10.1093/ofid/ofy210.793.

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Abstract Background Mycobacterium abscessus harbors a β-lactamase enzyme, BlaMab, able to hydrolyze penicillins, most cephalosporins and carbapenems. As of today, management of M. abscessus with β-lactams does not include combination of β-lactamase inhibitors. The potential benefit of combinations of several β-lactams with new diazabicyclooctane (DBO) inhibitors, such as relebactam and avibactam, has not been well studied. Based upon the ability to inhibit BlaMab by highly potent DBO inhibitors, our goal herein was to investigate the efficacy of a novel combination, ceftaroline (CEF) and aviba

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Therien, Alex G., Joann L. Huber, Kenneth E. Wilson та ін. "Broadening the Spectrum of β-Lactam Antibiotics through Inhibition of Signal Peptidase Type I". Antimicrobial Agents and Chemotherapy 56, № 9 (2012): 4662–70. http://dx.doi.org/10.1128/aac.00726-12.

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ABSTRACTThe resistance of methicillin-resistantStaphylococcus aureus(MRSA) to all β-lactam classes limits treatment options for serious infections involving this organism. Our goal is to discover new agents that restore the activity of β-lactams against MRSA, an approach that has led to the discovery of two classes of natural product antibiotics, a cyclic depsipeptide (krisynomycin) and a lipoglycopeptide (actinocarbasin), which potentiate the activity of imipenem against MRSA strain COL. We report here that these imipenem synergists are inhibitors of the bacterial type I signal peptidase SpsB

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MacDougall, Conan. "Beyond Susceptible and Resistant, Part I: Treatment of Infections Due to Gram-Negative Organisms With Inducible β-Lactamases". Journal of Pediatric Pharmacology and Therapeutics 16, № 1 (2011): 23–30. http://dx.doi.org/10.5863/1551-6776-16.1.23.

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ABSTRACT Inactivation of β-lactams by the action of β-lactamase enzymes is the most common mode of resistance to these drugs among Gram-negative organisms. The genomes of some key clinical pathogens such as Enterobacter and Pseudomonas encode AmpC, an inducible chromosomal β-lactamase. The potent activity of AmpC against broad-spectrum β-lactams complicates treatment of organisms with this gene. Antibiotic exposure can select for mutants expressing high levels of this enzyme, leading to the emergence of resistant isolates and failure of therapy, even when the initial isolate is fully susceptib

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Kidwai, M., P. Sapra та K. R. Shushan. "Synthetic Strategies and Medicinal Properties of β-Lactams". Current Medicinal Chemistry 6, № 3 (1999): 195–215. http://dx.doi.org/10.2174/0929867306666220208205333.

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Abstract: More than five decades since the Discovery of Penicillin, the chemistry and biological activity of -lactams continue to attract the wide spread attention of research workers. Owing to high efficacy and extremely safe toxicological profile, they are agents of choice in the current therapeutic index for the bacterial infectious diseases. Tremendous efforts have been made into synthesis and structural modification of the -lactam nucleus to increase antimicrobial activity and pharmacokinetic performance. These efforts resulted in the development of ampicillin, amoxicillin and a group of

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Gostev, Vladimir V., O. E. Punchenko, and Sergey V. Sidorenko. "The current view on betalactam resistance in Staphylococcus aureus." Clinical Microbiology and Antimicrobial Chemotherapy 23, no. 4 (2021): 375–87. http://dx.doi.org/10.36488/cmac.2021.4.375-387.

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The review presents the current view on the different resistance mechanisms of Staphylococcus aureus to beta-lactams, which are ones of the main antibiotics of choice for the treatment of staphylococcal infections. Currently, there are several mechanisms of resistance such as production of staphylococcal beta-lactamase (blaZ), which provides resistance to penicillins and aminopenicillins. Another one is the presence of an alternative penicillin-binding protein (PBP2a), which is the main marker of methicillinresistant S. aureus (MRSA), virtually providing resistance to all beta-lactams, with th

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Drawz, Sarah M., та Robert A. Bonomo. "Three Decades of β-Lactamase Inhibitors". Clinical Microbiology Reviews 23, № 1 (2010): 160–201. http://dx.doi.org/10.1128/cmr.00037-09.

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SUMMARYSince the introduction of penicillin, β-lactam antibiotics have been the antimicrobial agents of choice. Unfortunately, the efficacy of these life-saving antibiotics is significantly threatened by bacterial β-lactamases. β-Lactamases are now responsible for resistance to penicillins, extended-spectrum cephalosporins, monobactams, and carbapenems. In order to overcome β-lactamase-mediated resistance, β-lactamase inhibitors (clavulanate, sulbactam, and tazobactam) were introduced into clinical practice. These inhibitors greatly enhance the efficacy of their partner β-lactams (amoxicillin,

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Tsang, Wing Y., Naveed Ahmed, Karl Hemming та Michael I. Page. "Competitive endo- and exo-cyclic CN fission in the hydrolysis of N-aroyl β-lactams". Canadian Journal of Chemistry 83, № 9 (2005): 1432–39. http://dx.doi.org/10.1139/v05-153.

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The balance between endo- and exo-cyclic CN fission in the hydrolysis of N-aroyl β-lactams shows that the difference in reactivity between strained β-lactams and their acyclic analogues is minimal. Attack of hydroxide ion occurs preferentially at the exocyclic acyl centre rather than that of the β-lactam during the hydrolysis of N-p-nitrobenzoyl β-lactam. In general, both endo- and exo-cyclic CN bond fission occurs in the alkaline hydrolysis of N-aroyl β-lactams, the ratio of which varies with the aryl substituent. Hence, the Brønsted β-values differ for the two processes: 0.55 for the ring

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Muñoz-Muñoz, Lara, José A. Aínsa та Santiago Ramón-García. "Repurposing β-Lactams for the Treatment of Mycobacterium kansasii Infections: An In Vitro Study". Antibiotics 12, № 2 (2023): 335. http://dx.doi.org/10.3390/antibiotics12020335.

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Mycobacterium kansasii (Mkn) causes tuberculosis-like lung infection in both immunocompetent and immunocompromised patients. Current standard therapy against Mkn infection is lengthy and difficult to adhere to. Although β-lactams are the most important class of antibiotics, representing 65% of the global antibiotic market, they have been traditionally dismissed for the treatment of mycobacterial infections, as they were considered inactive against mycobacteria. A renewed interest in β-lactams as antimycobacterial agents has shown their activity against several mycobacterial species, including

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Tajada, P., J. L. Gomez-Graces, J. I. Alós, D. Balas, and R. Cogollos. "Antimicrobial susceptibilities of Campylobacter jejuni and Campylobacter coli to 12 beta-lactam agents and combinations with beta-lactamase inhibitors." Antimicrobial Agents and Chemotherapy 40, no. 8 (1996): 1924–25. http://dx.doi.org/10.1128/aac.40.8.1924.

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The in vitro activities of 12 beta-lactam agents against 100 thermophilic Campylobacter strains were tested. Beta-Lactamase production was detected in 88% of all strains tested. Clavulanic acid was the best inhibitor by susceptibility testing. The beta-lactams which displayed high levels of in vitro activity against Campylobacter isolates were imipenem, amoxicillin-clavulanic acid, and cefepime and, to a lesser degree, amoxicillin, ampicillin, and cefotaxime.

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Hussan, Jagir R., Stuart G. Irwin, Brya Mathews, Simon Swift, Dustin L. Williams, and Jillian Cornish. "Optimal dose of lactoferrin reduces the resilience of in vitro Staphylococcus aureus colonies." PLOS ONE 17, no. 8 (2022): e0273088. http://dx.doi.org/10.1371/journal.pone.0273088.

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The rise in antibiotic resistance has stimulated research into adjuvants that can improve the efficacy of broad-spectrum antibiotics. Lactoferrin is a candidate adjuvant; it is a multifunctional iron-binding protein with antimicrobial properties. It is known to show dose-dependent antimicrobial activity against Staphylococcus aureus through iron sequestration and repression of β–lactamase expression. However, S. aureus can extract iron from lactoferrin through siderophores for their growth, which confounds the resolution of lactoferrin’s method of action. We measured the minimum inhibitory con

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Zhang, Song, Xinyu Liao, Tian Ding та Juhee Ahn. "Role of β-Lactamase Inhibitors as Potentiators in Antimicrobial Chemotherapy Targeting Gram-Negative Bacteria". Antibiotics 13, № 3 (2024): 260. http://dx.doi.org/10.3390/antibiotics13030260.

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Since the discovery of penicillin, β-lactam antibiotics have commonly been used to treat bacterial infections. Unfortunately, at the same time, pathogens can develop resistance to β-lactam antibiotics such as penicillins, cephalosporins, monobactams, and carbapenems by producing β-lactamases. Therefore, a combination of β-lactam antibiotics with β-lactamase inhibitors has been a promising approach to controlling β-lactam-resistant bacteria. The discovery of novel β-lactamase inhibitors (BLIs) is essential for effectively treating antibiotic-resistant bacterial infections. Therefore, this revie

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Kimura, Soichiro, Masaji Ishiguro, Yoshikazu Ishii, Jimena Alba, and Keizo Yamaguchi. "Role of a Mutation at Position 167 of CTX-M-19 in Ceftazidime Hydrolysis." Antimicrobial Agents and Chemotherapy 48, no. 5 (2004): 1454–60. http://dx.doi.org/10.1128/aac.48.5.1454-1460.2004.

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ABSTRACT CTX-M-19 is a recently identified ceftazidime-hydrolyzing extended-spectrum β-lactamase, which differs from the majority of CTX-M-type β-lactamases that preferentially hydrolyze cefotaxime but not ceftazidime. To elucidate the mechanism of ceftazidime hydrolysis by CTX-M-19, the β-lactam MICs of a CTX-M-19 producer, and the kinetic parameters of the enzyme were confirmed. We reconfirmed here that CTX-M-19 is also stable at a high enzyme concentration in the presence of bovine serum albumin (20 μg/ml). Under this condition, we obtained more accurate kinetic parameters and determined th

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Tribuddharat, Chanwit, Richard A. Moore, Patricia Baker та Donald E. Woods. "Burkholderia pseudomallei Class A β-Lactamase Mutations That Confer Selective Resistance against Ceftazidime or Clavulanic Acid Inhibition". Antimicrobial Agents and Chemotherapy 47, № 7 (2003): 2082–87. http://dx.doi.org/10.1128/aac.47.7.2082-2087.2003.

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ABSTRACT Burkholderia pseudomallei, the causative agent of melioidosis, is inherently resistant to a variety of antibiotics including aminoglycosides, macrolides, polymyxins, and β-lactam antibiotics. Despite resistance to many β-lactams, ceftazidime and β-lactamase inhibitor-β-lactam combinations are commonly used for treatment of melioidosis. Here, we examine the enzyme kinetics of β-lactamase isolated from mutants resistant to ceftazidime and clavulanic acid inhibition and describe specific mutations within conserved motifs of the β-lactamase enzyme which account for these resistance patter

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Fisher, Jed F., та Shahriar Mobashery. "β-Lactams from the Ocean". Marine Drugs 21, № 2 (2023): 86. http://dx.doi.org/10.3390/md21020086.

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The title of this essay is as much a question as it is a statement. The discovery of the β-lactam antibiotics—including penicillins, cephalosporins, and carbapenems—as largely (if not exclusively) secondary metabolites of terrestrial fungi and bacteria, transformed modern medicine. The antibiotic β-lactams inactivate essential enzymes of bacterial cell-wall biosynthesis. Moreover, the ability of the β-lactams to function as enzyme inhibitors is of such great medical value, that inhibitors of the enzymes which degrade hydrolytically the β-lactams, the β-lactamases, have equal value. Given this

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Masuda, Nobuhisa, Naomasa Gotoh, Chie Ishii, Eiko Sakagawa, Satoshi Ohya та Takeshi Nishino. "Interplay between Chromosomal β-Lactamase and the MexAB-OprM Efflux System in Intrinsic Resistance to β-Lactams inPseudomonas aeruginosa". Antimicrobial Agents and Chemotherapy 43, № 2 (1999): 400–402. http://dx.doi.org/10.1128/aac.43.2.400.

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ABSTRACT We investigated the role of chromosomal β-lactamase and the MexAB-OprM efflux system in intrinsic resistance to β-lactams inPseudomonas aeruginosa. Determination of the susceptibilities of a series of isogenic mutants with impaired production of the β-lactamase and the efflux system to 16 β-lactams including penicillins, cephems, oxacephems, carbapenems, and a monobactam demonstrated that the intrinsic resistance of P. aeruginosa to most of the β-lactams is due to the interplay of both factors.

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Valtonen, Satu J., Jussi S. Kurittu та Matti T. Karp. "A Luminescent Escherichia coli Biosensor for the High Throughput Detection of β-Lactams". Journal of Biomolecular Screening 7, № 2 (2002): 127–34. http://dx.doi.org/10.1177/108705710200700205.

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A group-specific bioluminescent Escherichia coli strain for studying the action of β-lactam antibiotics is described. The strain contains a plasmid, pBlaLux1, in which the luciferase genes from Photorhabdus luminescent are inserted under the control of the β-lactam-responsive element ampR/ampC from Citrobacter freundii. In the presence of β-lactams, the bacterial cells are induced to express the luciferase enzyme and three additional enzymes generating the substrate for the luciferase reaction. This biosensor for β-lactams does not need any substrate or cofactor additions, and the bioluminesce

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Hamerníková, Michaela, Jaroslav Havlíček, Romana Bláhová, Helena Pospíšilová, Hana Votavová, and Karel Kefurt. "6-Amino-2,6-dideoxy- or -2,3,6-trideoxyhexono-1,6-lactams: Synthesis and Conformation." Collection of Czechoslovak Chemical Communications 69, no. 4 (2004): 867–84. http://dx.doi.org/10.1135/cccc20040867.

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6-Amino-2,6-dideoxy-D-ribo-hexono-1,6-lactam (1a), 6-amino-2,6-dideoxy-D-arabino-hexono-1,6-lactam (2a), 6-amino-2,3,6-trideoxy-L-threo-hexono-1,6-lactam (3a) and per-O-acetyl derivatives 1b-3b were synthesized and their seven-membered lactam ring conformation was studied. 1H and 13C NMR spectra of the named lactams, measured at low temperature, always disclosed the presence of both 1,NC4 and 4C1,N conformations in ratios which were affected mainly by the stereochemistry of cyclohexane. There were no CD extremes over 200 nm found in water solutions of the lactams 1a and 2a, probably owing to t

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Hark-Khan, Raida, та William A. Moats. "Identification and Measurement of β-Lactam Antibiotic Residues in Milk: Integration of Screening Kits with Liquid Chromatography". Journal of AOAC INTERNATIONAL 78, № 4 (1995): 978–86. http://dx.doi.org/10.1093/jaoac/78.4.978.

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Abstract A procedure for identifying and quantitating violative β-lactams in milk is described. This procedure integrates β-lactam residue detection kits with the multiresidue automated liquid chromatographic (LC) cleanup method developed in our laboratory. Spiked milk was deproteinized, extracted, and subjected to reversed-phase LC using a gradient program that concentrated the β-lactams. Amoxicillin, ampicillin, cephapirin, ceftiofur, cloxacillin, and penicillin G were, thus, separated into 5 fractions that were subsequently tested for activity by using 4 kits. (3-lactams in the positive fra

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Stover, Kayla R., Katie E. Barber, and Jamie L. Wagner. "Allergic Reactions and Cross-Reactivity Potential with Beta-Lactamase Inhibitors." Pharmacy 7, no. 3 (2019): 77. http://dx.doi.org/10.3390/pharmacy7030077.

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Although beta-lactam allergies are an emerging focus of stewardship programs and interventions, less is publicly released regarding allergies to beta-lactamase inhibitors. This review presents and evaluates the data regarding allergic reactions with beta-lactamase inhibitors. Clavulanate, sulbactam, and tazobactam are beta-lactam-based beta-lactamase inhibitors that are combined with several penicillins or cephalosporins in order to preserve antimicrobial activity in the presence of beta-lactamases. Avibactam, relebactam, and vaborbactam are non-beta-lactam beta-lactamase inhibitors that are c

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Lagacé-Wiens, P. R. S., F. Tailor, P. Simner та ін. "Activity of NXL104 in Combination with β-Lactams against Genetically Characterized Escherichia coli and Klebsiella pneumoniae Isolates Producing Class A Extended-Spectrum β-Lactamases and Class C β-Lactamases". Antimicrobial Agents and Chemotherapy 55, № 5 (2011): 2434–37. http://dx.doi.org/10.1128/aac.01722-10.

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ABSTRACTThe novel non-β-lactam β-lactamase inhibitor NXL104, in combination with cefepime, ceftazidime, ceftriaxone, amdinocillin, and meropenem, was tested against 190 extended-spectrum β-lactamase (ESBL)-producingEscherichia coliandKlebsiella pneumoniaeisolates, 94 AmpC-hyperproducingE. coliisolates, and 8 AmpC/ESBL-coexpressingE. coliisolates. NXL104 restored 100% susceptibility to the partner cephalosporins for all isolates tested. Amdinocillin and meropenem MICs were modestly improved (2 to 32 times lower) by NXL104. These results suggest that NXL104 may be useful in combination with β-la

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Tebano, Gianpiero, Giulia la Martire, Luigi Raumer, et al. "Which Are the Best Regimens of Broad-Spectrum Beta-Lactam Antibiotics in Burn Patients? A Systematic Review of Evidence from Pharmacology Studies." Antibiotics 12, no. 12 (2023): 1737. http://dx.doi.org/10.3390/antibiotics12121737.

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Background: Burn injury causes profound pathophysiological changes in the pharmacokinetic/pharmacodynamic (PK/PD) properties of antibiotics. Infections are among the principal complications after burn injuries, and broad-spectrum beta-lactams are the cornerstone of treatment. The aim of this study was to review the evidence for the best regimens of these antibiotics in the burn patient population. Methods: We performed a systematic review of evidence available on MEDLINE (from its inception to 2023) of pharmacology studies that focused on the use of 13 broad-spectrum beta-lactams in burn patie

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Bryan, L. E., A. J. Godfrey та T. Schollardt. "Virulence of Pseudomonas aeruginosa strains with mechanisms of microbial persistence for β-lactam and aminoglycoside antibiotics in a mouse infection model". Canadian Journal of Microbiology 31, № 4 (1985): 377–80. http://dx.doi.org/10.1139/m85-072.

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A series of mutations and transductants producing low-level aminoglycoside and β-lactam antibiotic resistance of Pseudomonas aeruginosa have been constructed in an isogenic background. The phenotypes of these mutations are identical to or closely resemble those of clinical isolates of P. aeruginosa associated with therapeutic failure or microbial persistence in the presence of members of one or both groups of drugs. Virulence of the mutants was examined in an infection model using iron–dextran treated mice and bacteria grown in low-iron medium. All β-lactam resistant mutants affecting affinity

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Krey, Steven C., Jeff Waise, and Lee P. Skrupky. "Confronting the Challenge of Beta-Lactam Allergies: A Quasi-Experimental Study Assessing Impact of Pharmacy-Led Interventions." Journal of Pharmacy Practice 32, no. 2 (2017): 139–46. http://dx.doi.org/10.1177/0897190017743154.

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Objective: To improve allergy history documentation and increase the use of beta-lactams when appropriate in patients with a reported beta-lactam allergy. Methods: This pre–post study was conducted at a 167-bed tertiary care community hospital and evaluated multidisciplinary interventions on allergy documentation and antibiotic selection. Interventions included education, creation of local practice guidelines, and modified practices for pharmacists and pharmacy technicians. Inpatients with a reported beta-lactam allergy receiving at least 1 antibiotic for >24 hours were included; first admi

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Story-Roller, Elizabeth, та Gyanu Lamichhane. "803. Overcoming β-Lactam Resistance in Mycobacterium abscessus". Open Forum Infectious Diseases 5, suppl_1 (2018): S288. http://dx.doi.org/10.1093/ofid/ofy210.810.

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Abstract Background Mycobacterium abscessus (Mab) is an environmentally acquired nontuberculous mycobacterium (NTM) that causes severe pulmonary infections in patients with chronic lung disease, such as cystic fibrosis (CF). The incidence of drug-resistant Mab infections in CF patients in the United States is steadily rising, making it increasingly difficult to manage these often chronic and incurable infections. Mab requires two enzyme classes, l,d- and d,d-transpeptidases, to synthesize peptidoglycan (PG); an integral component of the bacterial cell wall. Each enzyme class is uniquely suscep

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Isoda, Motoyuki, Kazuyuki Sato, Yurika Kunugi, et al. "Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe." Beilstein Journal of Organic Chemistry 12 (July 27, 2016): 1608–15. http://dx.doi.org/10.3762/bjoc.12.157.

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An effective synthesis for syn-β-lactams was achieved using a Rh-catalyzed reductive Mannich-type reaction. A rhodium–hydride complex (Rh–H) derived from diethylzinc (Et2Zn) and a Rh catalyst was used for the 1,4-reduction of an α,β-unsaturated ester to give a Reformatsky-type reagent, which in turn, reacted with an imine to give the syn-β-lactam. Additionally, the reaction was applied to the synthesis of (±)-ezetimibe, a potent β-lactamic cholesterol absorption inhibitor.

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Skoglund, Erik, Henrietta Abodakpi, Rafael Rios, et al. "In Vivo Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa Arising by AmpC- and Non-AmpC-Mediated Pathways." Case Reports in Infectious Diseases 2018 (December 23, 2018): 1–4. http://dx.doi.org/10.1155/2018/9095203.

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Two pairs of ceftolozane/tazobactam susceptible/resistant P. aeruginosa were isolated from 2 patients after exposure to β-lactams. The genetic basis of ceftolozane/tazobactam resistance was evaluated, and β-lactam-resistant mechanisms were assessed by phenotypic assays. Whole genome sequencing identified mutations in AmpC including the mutation (V213A) and a deletion of 7 amino acids (P210–G216) in the Ω-loop. Phenotypic assays showed that ceftolozane/tazobactam resistance in the strain with AmpCV213A variant was associated with increased β-lactamase hydrolysis activity. On the other hand, the

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Barba, Victor, Cecilia Hernández, Susana Rojas-Lima, Norberto Farfán та Rosa Santillan. "Preparation of N-aryl-substituted spiro-β-lactams via Staudinger cycloaddition". Canadian Journal of Chemistry 77, № 12 (1999): 2025–32. http://dx.doi.org/10.1139/v99-212.

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The interest in the study of β-lactams continues due to their therapeutic importance as antibiotics. In this work, six spiro-β-lactams (7a-7c, 8a-8c) have been prepared using the [2+2] cycloaddition of isomaleimides to acid chlorides. The heterobicyclic structures obtained have been characterized by mass spectrometry, IR, NMR spectroscopy, and for compounds 7a, 7b, and 8b the X-ray crystallographic study showed a nearly planar arrangement for the β-lactam ring.Key words: β-lactams, azetidinone, isomaleimides, ketenes, X-ray crystallography.

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Sun, Shuhai, Zhuang Li, Zhixing Ren та Yu Li. "Multi-Dimensional Elimination of β-Lactams in the Rural Wetland: Molecule Design and Screening for More Antibacterial and Degradable Substitutes". Molecules 27, № 23 (2022): 8434. http://dx.doi.org/10.3390/molecules27238434.

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Restricted economic conditions and limited sewage treatment facilities in rural areas lead to the discharge of small-scale breeding wastewater containing higher values of residual beta-lactam antibiotics (β-lactams), which seriously threatens the aquatic environment. In this paper, molecular docking and a comprehensive method were performed to quantify and fit the source modification for the combined biodegradation of β-lactams. Using penicillin (PNC) as the target molecule, combined with contour maps for substitute modification, a three-dimensional quantitative structure–activity relationship

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De Angelis, Giulia, Paola Del Giacomo, Brunella Posteraro, Maurizio Sanguinetti та Mario Tumbarello. "Molecular Mechanisms, Epidemiology, and Clinical Importance of β-Lactam Resistance in Enterobacteriaceae". International Journal of Molecular Sciences 21, № 14 (2020): 5090. http://dx.doi.org/10.3390/ijms21145090.

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Despite being members of gut microbiota, Enterobacteriaceae are associated with many severe infections such as bloodstream infections. The β-lactam drugs have been the cornerstone of antibiotic therapy for such infections. However, the overuse of these antibiotics has contributed to select β-lactam-resistant Enterobacteriaceae isolates, so that β-lactam resistance is nowadays a major concern worldwide. The production of enzymes that inactivate β-lactams, mainly extended-spectrum β-lactamases and carbapenemases, can confer multidrug resistance patterns that seriously compromise therapeutic opti

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