The quinolones inhibit the essential bacterial enzymes DNA gyrase and topoisomerase IV, which alter DNA topology after inserting a double-stranded break. DNA gyrase exists as an A2B2 tetramer, encoded by the gyrA and gyrB genes, and catalyses negative DNA supercoiling. Topoisomerase IV exists as a C2E2 tetramer encoded by the parC and parE genes, and is involved in chromosome partitioning. Prev...

Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl) methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazi...

Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus isolates were exposed to subinhibitory MICs of ciprofloxacin, sparfloxacin, gatifloxacin, moxifloxacin, clinafloxacin, and gemifloxacin during a 10-day period. Subculturing led to resistance development, regardless of the initial potencies of the quinolones. None of the quinolones was associated with a significantly slo...

Superfusion of canine tracheal mucosa with 100 microg each of grepafloxacin and ciprofloxacin per ml reduced the electrical transepithelial potential difference in vivo by more than 50%. This effect was dose dependent, specific for new quinolones, and inhibited by Cl channel blockers, indicating that new quinolones attenuate Cl secretion across the airway epithelium.

Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazi...

Escherichia coli is an important pathogen of animals and humans that causes great financial cost in food production by causing disease in food animals. The quinolones are a class of synthetic antimicrobial agents with excellent activity against Escherichia coli and other Gram-negative bacteria used in human and veterinary medicine. Different quinolones are used to treat various conditions in an...

OBJECTIVES Quinolones accumulate in eukaryotic cells and show activity against a large array of intracellular organisms, but systematic studies aimed at examining their pharmacodynamic profile against intracellular bacteria are scarce. The present work aims at comparing intracellular-to-extracellular activities in this context. METHODS We assessed the activities of ciprofloxacin, levofloxacin...

The meta-analysis by SIEMPOS et al. [1] has shown equivalent efficacy of macrolides, quinolones and amoxicillin/clavulanate in the treatment of patients with acute bacterial exacerbation of chronic bronchitis (ABECB). Although quinolones are associated with better microbiological success and fewer recurrences of ABECB, certain points merit further discussion, especially in tuberculosis (TB) end...

An efficient and practical method for the direct cross-coupling between quinolones and a range of azoles was developed via copper-mediated C-H functionalization. This synthetic strategy provides a convenient access to a variety of C3-heteroaryl quinolones, quinolinone, nalidixic acid, uracil, pyridone and chromone derivatives, which are prominent structural motifs in many biologically active co...