Antibacterial Activity Of Fluoroquinolones Research Articles

Synthesis and antibacterial activity of fluoroquinolones with sterically hindered phenolic moieties

Synthesis and antibacterial activity of fluoroquinolones with sterically hindered phenolic moieties

Simultaneous quantification of levofloxacin, pefloxacin, ciprofloxacin and moxifloxacin in microvolumes of human plasma using high-performance liquid chromatography with ultraviolet detection.

Levofloxacin, pefloxacin, ciprofloxacin and moxifloxacin are four fluoroquinolones used in the treatment of serious bacterial infections. The antibacterial activity of fluoroquinolones is concentration dependent. Therefore, therapeutic drug monitoring in daily clinical practice is warranted to ensure the therapy's efficacy and prevent bacterial resistance. The purpose of the present study was to develop a method using high-pressure liquid chromatography with an ultraviolet detector for simultaneous quantification of these four fluoroquinolones in human plasma. A 50 μL aliquot of plasma was precipitated by 200 μL of methanol using gatifloxacin as internal standard. The chromatographic separation was performed on a Kinetex XB-C18 column using a mobile phase composed of a mixture of orthophosphoric acid 0.4% (v/v), acetonitrile and methanol at a flow rate of 1.2 mL/min. Dual UV wavelength mode was used, with levofloxacin and moxifloxacin monitored at 293 nm, and pefloxacin and ciprofloxacin monitored at 280 nm. The calibration was linear over the ranges of 0.125-25 mg/L for levofloxacin, 0.1-20mg/L for moxifloxacin and 0.05-10 mg/L for both pefloxacin and ciprofloxacin. Inter- and intra-day trueness and precision were <13% for all the compounds under study. The proposed method was simple, reliable, cost-effective and suitable for therapeutic drug monitoring or pharmacokinetics studies.

Comparative mutant prevention concentration and antibacterial activity of fluoroquinolones against Escherichia coli in diarrheic buffalo calves

Owing to emerging threat of antimicrobial resistance, mutant prevention concentration (MPC) is considered as an important parameter to evaluate the antimicrobials for their capacity to restrict/allow the emergence of resistant mutants. Therefore, MPCs of ciprofloxacin, enrofloxacin, levofloxacin, moxifloxacin, and norfloxacin were determined against Escherichia coli isolates of diarrheic buffalo calves. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were also established. The MICs of ciprofloxacin, enrofloxacin, levofloxacin, moxifloxacin and norfloxacin were 0·009, 0·022, 0·024, 0·028, and 0·036 μg/ml, respectively. The MBCs obtained were very close to the MICs of respective drugs that suggested a bactericidal mode of action of antimicrobials. The MPCs (μg/ml) of ciprofloxacin (4·2×MIC), moxifloxacin (4·8×MIC), and norfloxacin (5·1×MIC) were approximately equal but slightly lower than enrofloxacin (7·6×MIC) and levofloxacin (8·5×MIC) against clinical isolates of E. coli. The MPC data suggested that enrofloxacin has the potential for restricting the selection of E. coli mutants during treatment at appropriate dosing.

Design, synthesis and antibacterial activity of fluoroquinolones containing bulky arenesulfonyl fragment: 2D-QSAR and docking study

Here in, we report the design, synthesis, and antibacterial activity of series of bulky arenesulfonamido derivatives using ciprofloxacin and norfloxacin as scaffolds. All the synthesized compounds were investigated in vitro for their antibacterial activities against two Gram-positive and two Gram-negative organisms using dilution broth method. Among the tested compounds examined, compounds 3–7 showed significance difference from the standard drug ciprofloxacin. 2D-QSAR study provides details on the fine relationship linking structure and activity and offers clues for structural modifications that can improve the activity. Docking study of the compound 3b into the active site of the topoisomerase II DNA-gyrase enzymes revealed a similar binding mode to ciprofloxacin with additional classical and nonclassical hydrogen bonds.

The etiology of respiratory tract infections and the antibacterial activity of fluoroquinolones and other oral antibacterial agents against respiratory pathogens

'Department of Medical Microbiology, Fondation HBpital Saint Joseph, Paris, France; 2Anti-infective Research Group, Department of Clinical Pharmacology, Hoechst Marion Roussel, France; 3Hershey Medical Center, Hershey, USA; 4Max Von Pettenkofer Institute, Munchen, Germany; 5Department of Pathology, University Hospitals of Cleveland, Cleveland, Ohio, USA; 61nstitute of Microbiology, University of Genoa Medical School, Genoa, Italy; 'Department of Medical Microbiology, City Hospital NHS Trust, Birmingham, UK

Antibacterial Activity of Fluoroquinolones Local Clinical Isolates from a Referral Center in Riyadh

A total of 1,034 clinical isolates from a tertiary care center were tested against six fluoroquinolones, namely norfloxacin, ciprofloxacin, lomefloxacin, sparfloxacin, temafloxacin, and CI-960. Bacteria tested consisted of 579 strains of Enterobacteriaceae, 98 pseudomonads, 51 Acinetebacter, 56 enterococci and 250 isolates of staphylococci. All six fluoroquinolones showed excellent in vitro activity inhibiting >90% of Escherichia coli at an MIC of < 0.03-0.5 mg/L, Klebsiella pneumoniae at 0.12-2.0 mg/L, Enterobacter at 0.12-2.0 mg/L, Serratia marcescens at 0.12-2.0 mg/L, Pseumodonas aeruginosa at 0.5-2.0 mg/L, Staphylococcus aureus at < 0.03-1.0 mg/L, and coagulase negative staphylococci at an MIC of 0.12-2.0 mg/L Xanthomonas maltophilia showed some resistance to norfloxacin, ciprofloxacin, lomefloxacin and temafloxacin, but was inhibited by sparfloxacin and CI-960. A majority of isolates of enterococci were resistant to norfloxacin, ciprofloxacin, lomefloxacin, and CI-960, but sparfloxacin and temafloxacin inhibited 92% and 82% of these strains, respectively.

DNA - gyrase inhibition and antibacterial activity of fluoro-quinolones: influence of the position of the fluorine(s).

A series of fluoro-quinolones was evaluated for antibacterial activity and DNA-gyrase inhibitory potency. The relative enhancement of the overall antibacterial activity resulting from C-6 or C-8 fluorine substituent was not accompanied with a major change of DNA-gyrase inhibitory potency.

Antibacterial activity of fluoroquinolones in combination with zidovudine

Since patients with AIDS may receive fluoroquinolones concurrently with zidovudine, the antibacterial interaction of these drugs was investigated. No evidence was found of antagonism between zidovudine and ciprofloxacin, DR-3355, enoxacin, lomefloxacin or ofloxacin against enterobacteria, staphylococci or Pseudomonas aeruginosa. Furthermore, the bactericidal activity of the fluoroquinolones against selected enterobacteria in nutrient broth was not affected by a clinically achievable concentration of zidovudine. It seems unlikely that zidovudine will have an adverse effect on the antibacterial activity of the fluoroquinolones in patients with AIDS.