Elucidating the leaving group effect in the .beta.-lactam ring opening mechanism of cephalosporins

1985 ◽  
Vol 50 (6) ◽  
pp. 886-888 ◽  
Author(s):  
Donald B. Boyd
1984 ◽  
Vol 106 (13) ◽  
pp. 3820-3825 ◽  
Author(s):  
Michael I. Page ◽  
Philip Proctor
Keyword(s):  

Author(s):  
Kavi Aniis ◽  
Rajamanikandan Kcp ◽  
Arvind Prasanth D

<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>


1981 ◽  
Vol 20 (11) ◽  
pp. 3728-3730 ◽  
Author(s):  
Massimiliano. Bonivento ◽  
Luciano. Canovese ◽  
Lucio. Cattalini ◽  
Giampaolo. Marangoni ◽  
Gianni. Michelon ◽  
...  

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