New synthesis of oxime-type beta-lactam antibiotics

1989 ◽  
Vol 54 (6) ◽  
pp. 1734-1745 ◽  
Author(s):  
Martin Mandel ◽  
Ludvík Novák ◽  
Miroslav Rajšner ◽  
Jiří Holubek ◽  
Vladislava Holá
Keyword(s):  
Phosphorus Pentachloride ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Gram Positive ◽  
Gram Negative ◽  
Beta Lactam Antibiotics ◽  
New Synthesis ◽  
Trimethylsilyl Derivatives ◽  
Derivatives Of

Reaction of anhydrous acids II with phosphorus pentachloride afforded hydrochlorides of chlorides III which were used in acylations of N,O-bis(trimethylsilyl) derivatives of 6-aminopenicillanic and 7-aminodeacetoxycephalosporanic acid. Change of the (Z)-configuration of the alkoxyimino group during the synthesis was observed only in the methoxyimino series. The prepared penicillins IV are effective against gram-positive as well as gram-negative bacteria.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

scholarly journals Improved Derivatives of Bactenecin, a Cyclic Dodecameric Antimicrobial Cationic Peptide

1999 ◽  
Vol 43 (5) ◽  
pp. 1274-1276 ◽  
Author(s):  
Manhong Wu ◽  
Robert E. W. Hancock
Keyword(s):  
Amino Acid ◽  
Antimicrobial Peptide ◽  
Tryptophan Residue ◽  
Gram Negative Bacteria ◽  
Cationic Peptide ◽  
Gram Positive ◽  
Antimicrobial Spectrum ◽  
Gram Negative ◽  
Derivatives Of

ABSTRACT Both linear and cyclic derivatives of the cyclic 12-amino-acid antimicrobial peptide bactenecin were designed based on optimization of amphipathicity and charge location. In general, increasing the number of positive charges at the N and C termini and adding an extra tryptophan residue in the loop not only increased the activities against both gram-positive and gram-negative bacteria but also broadened the antimicrobial spectrum.

scholarly journals Combination antibiotic therapy versus monotherapy in the treatment of acute exacerbations of chronic obstructive pulmonary disease: an open-label randomized trial

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Phuong Nguyen Thi Thu ◽  
Minh Ngo Thị Huong ◽  
Ngan Tran Thi ◽  
Hoi Nguyen Thanh ◽  
Khue Pham Minh
Keyword(s):  
Clinical Success ◽  
Chronic Obstructive ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Open Label ◽  
Obstructive Pulmonary Disease ◽  
Gram Negative ◽  
Copd Exacerbations ◽  
Beta Lactam Antibiotics ◽  
Acute Exacerbations

Abstract Background The role of antibiotics in the treatment of chronic obstructive pulmonary disease (COPD) exacerbations and their effectiveness in combination have not been clearly established. To determine whether using a combination of fluoroquinolones and beta-lactams improves the clinical and microbiological efficacy of antibiotics on day 20 of treatment, we conducted an open-label randomized trial based on clinical outcomes, microbiological clearance, spirometry tests, and signs of systemic inflammation in patients hospitalized with acute exacerbations of COPD. Methods We enrolled 139 subjects with COPD exacerbations, defined as acute worsening of respiratory symptoms leading to additional treatment. Patients were divided randomly into two groups: 79 patients using beta-lactam antibiotics alone and 60 using beta-lactam antibiotics plus fluoroquinolones. Clinical and microbiological responses, spirometry tests, symptom scores, and serum C-reactive protein (CRP) levels were evaluated. Results Clinical success, lung function, and symptoms were similar in patients with or without fluoroquinolone administration on days 10 and 20. Combination therapy was superior in terms of microbiological outcomes and reduction in serum CRP value. Although equivalent to monotherapy in terms of clinical success, the combination showed superiority in terms of microbiological success and a decrease in CRP. The combination therapy group had a higher microbiological success rate with gram-negative bacteria than the monotherapy group with Pseudomonas aeruginosa (100% vs. 33.3%, respectively) and Acinetobacter baumanii (100% vs. 20%, respectively) (P < 0.05). Conclusions Concomitant use of fluoroquinolone and beta-lactam antibiotics for bacterial infections during COPD exacerbations caused by gram-negative bacteria appear to be effective and should be applied in clinical practice.

scholarly journals Clinical Relevance of Antibiotic Susceptibility Profiles for Screening Gram-negative Microorganisms Resistant to Beta-Lactam Antibiotics

2020 ◽  
Vol 8 (10) ◽  
pp. 1555 ◽  
Author(s):  
Francisco Montiel-Riquelme ◽  
Elisabeth Calatrava-Hernández ◽  
Miguel Gutiérrez-Soto ◽  
Manuela Expósito-Ruiz ◽  
José María Navarro-Marí ◽  
...  
Keyword(s):  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Gram Negative ◽  
Extended Spectrum Beta Lactamase ◽  
Beta Lactam Antibiotics ◽  
Clinical Laboratories ◽  
Phenotypic Methods ◽  
Susceptibility Profiles

The increasing resistance to antibiotics is compromising the empirical treatment of infections caused by resistant bacteria. Rapid, efficient, and clinically applicable phenotypic methods are needed for their detection. This study examines the phenotypic behavior of β-lactam-resistant Gram-negative bacteria grown on ChromID ESBL medium with ertapenem, cefoxitin, and cefepime disks, reports on the coloration of colonies, and establishes a halo diameter breakpoint for the detection of carbapenemase-producing bacteria. We studied 186 β-lactam-resistant Gram-negative microorganisms (77 with extended spectrum beta lactamase (ESBL), 97 with carbapenemases, and 12 with AmpC β-lactamases (AmpC)). Susceptibility profiles of Gram-negative bacteria that produced ESBL, AmpC, and carbapenemases were similar to the expected profiles, with some differences in the response to cefepime of ESBL-producing microorganisms. Coloration values did not differ from those described by the manufacturer of ChromID ESBL medium. In the screening of carbapenemase production, inhibition halo diameter breakpoints for antibiotic resistance were 18 mm for Enterobacterales and ertapenem, 18 mm for Pseudomonas and cefepime, and 16 mm for Acinetobacter baumannii and cefepime. This innovative phenotypic approach is highly relevant to clinical laboratories, combining susceptibility profiles with detection by coloration of high-priority resistant microorganisms such as carbapenemase-producing A. baumannii, carbapenemase-producing Pseudomonas spp., and ESBL and/or carbapenemase-producing Enterobacterales.

Characterization of eight beta-lactamases of Gram-negative bacteria

1982 ◽  
Vol 152 (2) ◽  
pp. 567-571
Author(s):  
T Sawai ◽  
M Kanno ◽  
K Tsukamoto
Keyword(s):  
Assay Method ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Ph Optimum ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Beta Lactam Antibiotics ◽  
R Plasmids ◽  
Ph Stat ◽  
Species Specific

Eight kinds of beta-lactamases produced by gram-negative bacteria were characterized by the following properties: molecular weight, isoelectric point, pH optimum, molecular activity, immunochemical reactivity, and kinetic parameters with respect to twelve kinds of common beta-lactam antibiotics. These beta-lactamases included two types of penicillinases mediated by R plasmids and six kinds of species-specific cephalosporinases. To determine a reliable value of the kinetic parameter, Km, we introduced a continuous and acidimetric assay method of beta-lactamase activity with a pH stat.

scholarly journals Synthesis and Evaluation of Antimicrobial Activity of Nitrones from Derivatives of Aryl-Substituted Dihydroisoquinoline

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Mouna Bouzid ◽  
Raed Abdennabi ◽  
Mohamed Damak ◽  
Majed Kammoun
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
High Purity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Derivatives Of

This paper describes the synthesis of a series of dihydroisoquinoline nitrones by isomerization of the corresponding oxaziridines. Nitrones4a–cwere obtained in excellent yields and high purity by a simple and effective method from the isomerization of oxaziridines. The synthesized compounds were also evaluated for their antibacterial activity against Gram-positive and Gram-negative bacteria and fungus.

scholarly journals Monitoring of gram-negative bacteria and antibiotic resistance in osteomyelitis

2020 ◽  
Vol 26 (4) ◽  
pp. 544-547
Author(s):  
I.V. Shipitsyna ◽  
◽  
E.V Osipova ◽  
D.S. Leonchuk ◽  
A.S. Sudnitsyn ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Beta Lactam ◽  
Gram Negative ◽  
Regular Monitoring ◽  
Beta Lactam Antibiotics ◽  
Bacterial Morphology ◽  
Acinetobacter Sp ◽  
Drug Resistant Strains

Introduction There is an urgent need for a surveillance system of regular monitoring of specific bacteria inducing various types of osteomyelitis to identify resistant isolates and optimize the use of antibiotics. Objective: monitoring of specific gram-negative bacteria and analysis of the antibiotic resistance of the strains isolated from osteomyelitis patients over a three-year period. Results and discussion P. aeruginosa was the first most common pathogen among gram-negative microorganisms isolated from the patients between 2017 and 2019. Prevalence of the isolates identified in 2019 decreased by 9.6 % as compared to 2017. Next frequently encountered clinical isolates were Enterobacter sp., Acinetobacter sp., Klebsiella sp. There was a twofold increase in K. pneumoniae strains isolated in 2019. Analysis of antibiotic susceptibility testing data revealed multiresistance of the Acinetobacter sp. strains in 2019 despite the total decrease in resistant isolates in 2017 and 2018. Among non-fermenting gram-negative rods, the species being resistant to imipenem were shown to increase by 5.4 times. Overall antibiotic resistance was on rise. Increased antimicrobial resistance to beta-lactam antibiotics also combined with BLaC inhibitors was observed in Enterobacteriaceae population. Meropenem was found to be effective against most bacteria with growing drug resistance observed as compared with recent years. The antibiotic resistance profiles of Klebsiella sp. strains appeared to be high at antimicrobial testing. Conclusion Diverse bacterial morphology of gram-negative species and increasing proportion of drug-resistant strains isolated in osteomyelitis cases have necessitated regular monitoring of multiresistant clinical isolates for adjustment of empirical antibiotic therapies.

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