نتایج جستجو برای: quinolone imaging
تعداد نتایج: 460582 فیلتر نتایج به سال:
We have demonstrated that, in Escherichia coli, quinolone antimicrobial agents target topoisomerase IV (topo IV). The inhibition of topo IV becomes apparent only when gyrase is mutated to quinolone resistance. In such mutants, these antibiotics caused accumulation of replication catenanes, which is diagnostic of a loss of topo IV activity. Mutant forms of topo IV provided an additional 10-fold ...
Although quinolones have been in clinical use for decades, the mechanism underlying drug activity and resistance has remained elusive. However, recent studies indicate that clinically relevant quinolones interact with Bacillus anthracis (Gram-positive) topoisomerase IV through a critical water-metal ion bridge and that the most common quinolone resistance mutations decrease drug activity by dis...
30 We studied a collection of 105 clinical enterobacteria with unusual phenotypes of 31 quinolone susceptibility to analyze the occurrence of plasmid mediated quinolone resistance 32 (PMQR) and oqx genes and their implications on quinolone susceptibility. The oqxA and 33 oqxB genes were found in 31/34 (91%) Klebsiella pneumoniae and 1/3 Klebsiella oxytoca. 34 However, the oqxA/oqxB-harboring is...
Quinolone-resistant Salmonella strains were isolated from patient samples, and several quinolone-sensitive strains were used to analyze mutations in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC, and parE and to screen for plasmid-mediated quinolone resistance. Among the 21 strains that showed resistance to nalidixic acid and ciprofloxacin (MIC 0.125-2.0 μg/ml), 17 stra...
BACKGROUND Quinolone resistance in Enterobacteriaceae results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence ...
Benzo[/]-3-[(p-chlorophenylamino)(hydrazino)methyl]-4-hydroxy-1,2-dihydro-2-quinolone was prepared by the addition of H Br on — CH=N bond of the Schiff base followed by condensation with hydrazine and was used in the synthesis of different substituted triazolines borne on a quinolone moiety giving rise to a system of high probability to be of great biological importance. Some other derivatives ...
Quinolones are potent antibacterial agents that specifically target bacterial DNA gyrase and topoisomerase IV. Widespread use of these agents has contributed to the rise of bacterial quinolone resistance. Previous studies have shown that quinolone resistance arises by mutations in chromosomal genes. Recently, a multiresistance plasmid was discovered that encodes transferable resistance to quino...
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