ChemInform Abstract: SYNTHESES OF 2-AZETIDINONE (BETA-LACTAM) RING BY CHLOROSULFONYL ISOCYANATE

1973 ◽  
Vol 4 (38) ◽  
pp. no-no
Author(s):  
K. HIRAI ◽  
H. MATSUDA ◽  
Y. KISHIDA
Keyword(s):  
Beta Lactam ◽  
Chlorosulfonyl Isocyanate ◽  
Lactam Ring

scholarly journals PREVALENCE OF CEPHALOSPORIN-RESISTANT GRAM-NEGATIVE BACILLI FROM CLINICAL SAMPLES

2016 ◽  
pp. 176
Author(s):  
Kavi Aniis ◽  
Rajamanikandan Kcp ◽  
Arvind Prasanth D
Keyword(s):  
Clinical Samples ◽  
Beta Lactamase ◽  
Bacterial Isolates ◽  
Beta Lactam ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Lactam Ring ◽  
Esbl Producers

<p>ABSTRACT<br />Objective: Beta-lactams are the group of antibiotics that contain a ring called as “beta-lactam ring,” which is responsible for the antibacterial activity.<br />The presence of resistance among Gram-negative organisms is due to the production of beta-lactamases enzymes that hydrolysis the beta-lactam ring<br />thereby conferring resistance to the organism. This study is undertaken to determine the prevalence of extended-spectrum beta-lactamase (ESBL)<br />producing Gram-negative organism from clinical samples.<br />Methods: A total of 112 clinical samples were taken for this study. The combined disc synergistic test (CDST) was used for the phenotypic detection<br />of ESBL producers from the clinical samples. The genotypic identification of ESBL producers was carried out by alkaline lysis method by isolation of<br />plasmid DNA.<br />Result: A total of 87 bacterial isolates were isolated and identified. Among them, Klebsiella (41%) was the predominant organism followed by<br />Escherichia coli (33%), Proteus (10%), Pseudomonas (10%), and Serratia (6%). Among the various bacterial isolates, Klebsiella showed a higher<br />percentage of resistance. The CDST showed that 8 isolates of Klebsiella, 3 isolates of E. coli, and 1 isolate of Pseudomonas were found to be ESBL<br />producers. The genotypic confirmation showed that the two bacterial isolates, namely, Klebsiella and E. coli were found to possess temoniera (TEM)<br />gene which was the 400-500 bp conferring resistance to the antibiotics.<br />Conclusion: The results of this study suggest that early detection of ESBL producing Gram-negative organism is a very important step in planning the<br />therapy of patient in Hospitals. CDST continues to be a good indicator in the detection of ESBL producers.<br />Keywords: Beta-lactamases, Gram-negative bacilli, Extended-spectrum beta-lactamase, Resistance, Combined disc synergistic test.</p><p> </p>

scholarly journals The stereochemistry of β-lactam formation in cephalosporin biosynthesis

1978 ◽  
Vol 169 (3) ◽  
pp. 705-707 ◽  
Author(s):  
J A Huddleston ◽  
E P Abraham
Keyword(s):  
Cephalosporin C ◽  
Cephalosporium Acremonium ◽  
Beta Lactam ◽  
Lactam Ring

3H and 14C from (2R,3S)[U-14C,3-3H1]cysteine and (2R,3R)-[U-14C,2,3-3H2]cysteine were incorporated into cephalosporin C by Cephalosporium acremonium. Analysis of the radioactive cephalosporin C indicated that the formation of its beta-lactam ring occurs stereospecifically and with retention of configuration at C-3 of cysteine.

scholarly journals Analysis of the Degradation of Broad-Spectrum Cephalosporins by OXA-48-Producing Enterobacteriaceae Using MALDI-TOF MS

2019 ◽  
Vol 7 (12) ◽  
pp. 614
Author(s):  
Marina Oviaño ◽  
María Rosario Rodicio ◽  
Jürgen J. Heinisch ◽  
Rosaura Rodicio ◽  
Germán Bou ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Negative Control ◽  
Point Of View ◽  
Reaction Products ◽  
Beta Lactam ◽  
Maldi Tof Ms ◽  
E Coli ◽  
Maldi Tof ◽  
Lactam Ring ◽  
Tof Ms

The objective of the study was to evaluate the activity of OXA-48 against different broad-spectrum cephalosporins and to identify the reaction products by MALDI-TOF MS. The action of OXA-48 on cefotaxime, ceftazidime, and ceftriaxone was assessed by this method, using an Escherichia coli J53 transconjugant carrying only the ~62 Kb IncL plasmid containing the blaOXA-48 gene, and the same strain without any plasmid was included as a negative control. In addition, a collection of 17 clinical OXA-48-producing Enterobacteriaceae, which were susceptible to broad-spectrum cephalosporins, was evaluated. MALDI-TOF MS-based analysis of the E. coli transconjugant carrying the blaOXA-48-harboring plasmid, and also the clinical isolates, showed degradation of cefotaxime into two inactive compounds—decarboxylated and deacetylated cefotaxime (~370 Da) and deacetyl cefotaxime (~414 Da), both with the hydrolyzed beta-lactam ring. Reaction products were not obtained when the experiment was performed with ceftriaxone or ceftazidime. From a clinical point of view, our study supports the idea that the efficacy of cefotaxime against OXA-48-producing Enterobacteriaceae is doubtful, in contrast to ceftazidime and ceftriaxone which could be valid choices for treating infections caused by these bacteria. However, further clinical studies confirming this hypothesis are required.

Penicillin Update

1995 ◽  
Vol 16 (3) ◽  
pp. 83-90
Author(s):  
Stuart L. Goldstein ◽  
Sheldon L. Kaplan ◽  
Ralph D. Feigin
Keyword(s):  
Cell Wall ◽  
Mechanism Of Action ◽  
Antimicrobial Agents ◽  
Specific Activity ◽  
Basic Structure ◽  
Penicillin G ◽  
Side Chain ◽  
Beta Lactam ◽  
Lactam Ring ◽  
The Stability

Penicillin was discovered serendipitously by Alexander Fleming in 1928 while he was examining Staphylococcus variants. The first trials of penicillin in humans who had serious staphylococcal infections were undertaken more than I decade later and yielded impressive therapeutic results. Despite the introduction of numerous other antimicrobial agents and the emergence of many organisms resistant to penicillin, this agent remains a powerful and essential antibiotic 50 years after its first clinical application. Pharmacology The basic structure of the penicillins consists of the thiazolidine ring, a beta-lactam ring, and a side chain (Figure 1). The antimicrobial activity of all penicillins is produced by the thiazolidine/beta-lactam nucleus, and the organism-specific activity of a particular penicillin is determined by the side chain derivative. There are many naturally occurring side chain derivatives, but penicillin G is the most potent of these and, therefore, the only one used clinically. Semisynthetic penicillins are constructed from the basic penicillin nucleus with a side chain added. Each side chain alters the susceptibility of a particular penicillin to inactivating enzymes. MECHANISM OF ACTION All pencillins work by inhibiting bacterial cell wall synthesis, thereby affecting the stability of the cell wall and subsequent bacterial development. The cell wall is made of a peptidoglycan that is synthesized in three stages. MECHANISM OF ACTION

scholarly journals The inhibition of staphylococcal β-lactamase by clavulanic acid

1979 ◽  
Vol 179 (1) ◽  
pp. 67-76 ◽  
Author(s):  
C Reading ◽  
P Hepburn
Keyword(s):  
Enzyme Activity ◽  
Clavulanic Acid ◽  
Cell Extract ◽  
Beta Lactam ◽  
Beta Lactamases ◽  
First Order ◽  
Lactam Ring ◽  
Covalent Intermediate ◽  
Hydrolysis Of ◽  
Inhibited Enzyme

Clavulanic acid inhibited both the extracellular and cell-extract beta-lactamases of the four Staphylococcus aureus strains tested. The inhibition of S. aureus Russell cell-extract enzyme appeared to be active-site-directed and proceeded in a first-order fashion consistent with the formation of a covalent intermediate. Inhibited enzyme free of excess clavulanic acid was shown to regenerate enzyme activity slowly at pH 7.0, but the rate of reactivation increased at acid pH. When the enzyme was incubated with excess clavulanic acid complete inhibition was rapidly obtained, during further incubation clavulanic acid was shown to disappear slowly and complete loss of clavulanic acid from the reaction mixture coincided with the onset of the return of enzyme activity. A reactive enamine resulting from enzymic hydrolysis of the beta-lactam ring of clavulanic acid has been proposed as a possible intermediate in the inhibitory mechanism.

Characteristics of Aerobacter beta-lactamase

1968 ◽  
Vol 14 (2) ◽  
pp. 139-145 ◽  
Author(s):  
M. Goldner ◽  
D. G. Glass ◽  
P. C. Fleming
Keyword(s):  
Reaction Rates ◽  
Penicillin G ◽  
Cephalosporin C ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Lactam Ring ◽  
Rate Of Hydrolysis ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Pseudomonas Pyocyanea

In this investigation, Aerobacter cloacae is shown to inactivate cephalosporin by hydrolysis of its beta-lactam ring. This was demonstrated by iodine absorption and infrared absorption spectra.The values of the Michaelis constant obtained with cephalosporin C and deacetyl cephalosporin C indicate a great affinity of the Aerobacter's beta-lactamase for its substrate. The enzyme was most active at pH 7.0 and 37 C. Aqueous washings of the Aerobacter cells were a potent source of enzyme.The beta-lactamase of A. cloacae was active on both cephalosporin and penicillin. A higher rate of hydrolysis was observed with cephalosporin C and deacetyl cephalosporin C than with cephalothin and cephaloridine. The ratio of reaction rates on cephalosporin C to that on penicillin G was consistently of the order of 100 to 1. The activity on V, N, and especially the semisynthetic penicillins was also low.The A. cloacae enzyme was easily demonstrable in large amount without added inducer. By contrast, the activity of the beta-lactamase from Pseudomonas pyocyanea cannot be detected unless high concentrations of inducer are used.

Enzyme-linked immunosorbent assay for detection of antibodies to the unmodified beta-lactam ring

Allergy ◽  
1993 ◽  
Vol 48 (3) ◽  
pp. 151-157 ◽  
Author(s):  
G. F. Klein ◽  
U. Stanzl ◽  
P. O. Fritsch ◽  
J. M. Varga
Keyword(s):  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Beta Lactam ◽  
Lactam Ring

Examination of various Gram-negative bacteria for beta-lactamase activity

1968 ◽  
Vol 14 (5) ◽  
pp. 601-603 ◽  
Author(s):  
Pragna Desai ◽  
M. Goldner
Keyword(s):  
Quantitative Data ◽  
Direct Evidence ◽  
Bacterial Species ◽  
Penicillin G ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Infrared Spectrophotometry ◽  
Beta Lactam ◽  
Lactam Ring

The beta-lactamase activity in 10 bacterial species from different genera were evaluated where direct evidence and quantitative data were lacking. A quantitative iodometric method and infrared spectrophotometry were used for the determination of the beta-lactamase activity. The organisms tested were shown to have enzyme activity directed against the beta-lactam ring, and on the basis of the activity on two members of the beta-lactam group of antibiotics, penicillin G and cephalosporin C, a particular ratio was obtained for each species. This report supports the fact of the widespread distribution of beta-lactamase and reopens the question of its significance.

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