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At least 19 recordsLinked to original sources
PubMed1992

[Comparative activities in vitro of 4 quinolones (nalidixic acid, pefloxacin, norfloxacin, ofloxacin) on 13 bacterial species].

Nalidixic acid and three fluoroquinolones were tested on 389 strains belonging to 13 bacterial species, all isolated in Algeria. Ofloxacin, norfloxacin and pefloxacin have the same activities on E. coli, Acinetobacter and S. aureus. Norfloxacin has the best activity on Proteus, Enterobacter, Shigella and Klebsiella. Norfloxacin and ofloxacin have the same activities on S. typhi, Salmonella and choleric Vibrio. Norfloxacin has the same activity than pefloxacin on P. aeruginosa. It is necessary to prescribe a quinolone in the right way and to consider the pharmacokinetic properties.

Anti-Infective Agents↗
PubMed1992

Pyrimido[1,6-a]benzimidazoles: a new class of DNA gyrase inhibitors.

Substituted 4-quinolone- (1, A = CH) and 1,8-naphthyrid-4-one- (1, A = N) 3-carboxylic acids are currently the only classes of clinically useful antibacterial agents exerting their activity by inhibiting the subunit A of DNA gyrase. Pyrimido[1,6-alpha]benzimidazoles 11 have been found to be a new class of inhibitors of this enzyme. The design, synthesis, and biological activity of these compounds are reported.

Benzimidazoles↗
PubMed1992

Antibacterial activity of a 1,8-naphthyridine quinolone, PD 131628.

A new 1,8-naphthyridine quinolone antimicrobial, PD131628, was found to be as, or more active than ciprofloxacin or ofloxacin against Escherichia coli and considerably more active than the two 4-quinolone agents against staphylococci in terms of both MIC and OBC (the optimum bactericidal concentration, at which the rate of kill is greatest). In common with ciprofloxacin and ofloxacin, the rate of kill of PD131628 against Enterococcus faecalis was considerably slower than against the other three species tested. Bacterial protein synthesis, RNA synthesis and cell division were not required for the bactericidal activity of PD131628 against E. coli or the staphylococci, although the lethality of PD131628 in the absence of these activities was reduced.

Anti-Infective Agents↗
PubMed1992

Nucleotide sequence of the Staphylococcus aureus gyrB-gyrA locus encoding the DNA gyrase A and B proteins.

We have determined the nucleotide sequence of a 5.3-kb segment of the Staphylococcus aureus chromosome that includes the gyrA and gyrB genes coding for both subunits of DNA gyrase, the enzyme that catalyzes ATP-dependent DNA supercoiling. The gene order at this locus, dnaA-dnaN-recF-gyrB-gyrA, is similar to that found in the Bacillus subtilis replication origin region. S. aureus recF, gyrB, and gyrA genes are closely spaced, occupy the same reading frame, and may be coordinately expressed. The S. aureus gyrB and gyrA genes encode 640- and 889-residue proteins, respectively, that share strong homology with other bacterial gyrase subunits, notably those from B. subtilis. These results are discussed in regard to the mechanism of DNA gyrase and its role as a target for the 4-quinolones and other antistaphylococcal agents.

Amino Acid Sequence↗
PubMed1992

In vitro evaluation of BAY Y3118, a new full-spectrum fluoroquinolone.

BAY Y3118, 1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-8- chloro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid hydrochloride, is a new fluoroquinolone with antibacterial activity against an expanded spectrum of species including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Streptococcus pyogenes, and also anaerobes such as Bacteriodes fragilis and Clostridium perfringens. MIC90s for S. aureus, S. epidermidis, E. faecalis, and S. pneumoniae clinical isolates were 0.125, 0.25, 0.125 and 0.25 micrograms/ml, respectively. Against methicillin- and/or quinolone-resistant S. aureus, MIC50 levels of BAY Y3118 were 10- to 100-fold lower than those of tosufloxacin, sparfloxacin, or ciprofloxacin. The potency of BAY Y3118 against all members of the Enterobacteriaceae generally was equal to or 2-fold greater than that of ciprofloxacin or tosufloxacin. BAY Y3118 was also highly active against Haemophilus influenzae, Moraxella catarrhalis, Acinetobacter spp. and Pseudomonas aeruginosa. Increasing inoculum concentrations had a minimal effect on MIC determinations. The drug was determined to be bactericidal based upon reference MBCs and time-kill curves. From the results presented here, it was concluded that this new compound surpasses other known 4-quinolones both in spectrum and activity and that its further evaluation by in vitro, in vivo, and clinical studies seems warranted.

Anti-Infective Agents↗
PubMed1992

Synthesis and antibacterial activity of certain quinoline and quinazoline derivatives containing sulfide and sulfone moieties.

Some aryl and/or heterocyclic mercaptans were allowed to react with 8-quinolyl chloroacetate (II), 8-quinolinoxyacetyl chloride (IV) and 3-(2'-chloroethyl)-2-methyl-3,4-dihydroquinazolin-4-one (X) in dry benzene and/or sodium hydroxide in absolute ethanol to give corresponding 8-quinolyl-alpha-mercaptoacetate (V), 8-quinolinoxythioacetate (VI) and 3-(2'-arylmercaptoethyl)-2-methyl-4-(3H)quinazolin-4-ones or 3-(2'-heterocyclicmercaptoethyl)-2-methyl-4(3H)-quinazolin-4 -ones (XIa-h). The mercaptans V and XI were subjected to oxidation with hydrogen peroxide/acetic acid mixture (1:2) to afford the corresponding sulfones VII and XII. The structures of the synthesized compounds were elucidated by spectroscopic (IR and 1H-NMR) and elemental analyses. Some of these compounds were tested for their antimicrobial activities in comparison with tetracycline as a reference compound.

4-Quinolones↗
PubMed1992

Inducible stable DNA replication in Escherichia coli uvr+ and uvr- cells, treated with genotoxic chemicals.

Inducible stable DNA replication (iSDR) provoked by a damaging treatment with MMS, MNU, MNNG, NFAA, NFN, 4NQO, NAL or MMC, was followed in both repair-competent E. coli PQ35 and its uvrA derivative E. coli PQ37. In contrast to SOS-inducible mutagenesis, which is more pronounced in excision-deficient cells, iSDR was more obvious in repair-competent cells. This may be due to special features of iSDR and need not indicate involvement of the uvrA gene product in it.

4-Nitroquinoline-1-oxide↗
PubMed1992

Lipid peroxidation and loss of potassium from red blood cells produced by phototoxic quinolones.

Alterations of the cationic permeability of red blood cell membranes induced by the photosensitiser nalidixic acid were demonstrated by evaluating the potassium loss from intact erythrocytes. The results show that an increase in intracellular potassium efflux, precedes the photohemolysis induced by nalidixic acid. The addition of a nonpermeable osmotic solute, such as sucrose, inhibited photohemolysis but not the potassium loss, indicating a colloid osmotic lysis. Lipid peroxidation induced by nalidixic acid and other photosensitiser quinolones (oxolinic acid and rosoxacin) was time irradiation-dependent. Although rosoxacin was the most photoperoxidative, none of the three quinolones studied produced significant lipid peroxidation. However, of the three quinolones studied, only rosoxacin considerably diminished the percentage of the cholesterol extracted from red blood cell membranes. It is postulated that the increased cation permeability induced by nalidixic and oxolinic acids cannot be attributed to cholesterol oxidation nor to lipid peroxidation; a more probable mechanism is photo-oxidation of amino acid residues of the membrane proteins. However, the lysis induced by rosoxacin is caused by photo-oxidation of cholesterol, not excluding other cellular targets.

4-Quinolones↗
PubMed1979

High-performance liquid chromatographic analysis of rosoxacin and its N-oxide metabolite in plasma and urine.

A high-pressure liquid chromatographic method for the analysis of rosoxacin and its pyridyl N-oxide metabolite in plasma and urine extracts is described. A statistical evaluation of the assay data has shown acceptable accuracy and precision for 0.5 to 25 microgram of rosoxacin or the metabolite per ml of plasma and for 2.5 to 60 microgram/ml of either compound in urine. The minimum quantifiable level for rosoxacin was 0.13 microgram/ml in plasma and 0.64 microgram/ml in urine; for the metabolite in plasma and urine, the corresponding values were 0.21 and 0.60 microgram/ml, respectively. The method was applied to plasma and urine from three dogs medicated orally with 5 mg/kg of rosoxacin. The pharmacokinetic parameters calculated for rosoxacin were: plasma halflife, 1.9 h; plasma clearance, 65 ml/min; volume of distribution, 11.31. The average total urinary excretion of rosoxacin as free and conjugated rosoxacin and its free N-oxide was 7.7 +/- 0.2% over the 48-h collection period.

4-Quinolones↗
PubMed1992

In vitro antibacterial activities of tosufloxacin against and uptake of tosufloxacin by outer membrane mutants of Escherichia coli, Proteus mirabilis, and Salmonella typhimurium.

The antibacterial activities of tosufloxacin and other quinolones against and apparent uptakes of tosufloxacin and other quinolones by outer membrane mutants of Escherichia coli, Proteus mirabilis, and Salmonella typhimurium were studied. The hydrophobicity of tosufloxacin was nearly equal to that of ofloxacin or lower than those of sparfloxacin and nalidixic acid. OmpF- and OmpC-deficient E. coli and 40-kDa porin-deficient P. mirabilis mutants were twofold more susceptible to tosufloxacin and sparfloxacin but two- to fourfold less susceptible to other quinolones than their parent strains. In S. typhimurium lipopolysaccharide-deficient (rough) mutants, the differences in susceptibility to tosufloxacin were similar to those to sparfloxacin and nalidixic acid. The apparent uptake of tosufloxacin by intact cells was increased in porin-deficient mutants compared with that by their parent strain. These results suggest that the permeation route of tosufloxacin across the outer membrane is different from that of other fluoroquinolones and that tosufloxacin may permeate mainly through the nonporin pathway, presumably phospholipid bilayers. However, this characteristic is independent of the hydrophobicity of the molecule.

4-Quinolones↗
PubMed1992

Pefloxacin and ciprofloxacin in the treatment of uncomplicated gonococcal urethritis in males [corrected].

OBJECTIVE: To study the effectiveness of single-dose pefloxacin and ciprofloxacin in the treatment of uncomplicated gonococcal urethritis in males. SETTING: Department of STD Control, Kelantan Road, Singapore. METHOD: 160 male patients with uncomplicated gonococcal urethritis were assigned alternately to receive single oral doses of either pefloxacin 800 mg or ciprofloxacin 250 mg. RESULTS: Of the pefloxacin group 98.5% (65/66 patients) and of the ciprofloxacin group 98.6% (74/75 patients) were cured of gonorrhoea. The rates of post-gonococcal urethritis were 64.3% and 67.3% in the pefloxacin and ciprofloxacin groups, respectively. Both drugs were well tolerated and reported side-effects were minor and transient. There was a high incidence of penicillinase-producing gonococci (32.3%) and tetracycline resistant isolates with MIC > or = 2 mg/l (99.3%). High level tetracycline resistance (MIC > or = 16 mg/l) was found in 7.4% of isolates. CONCLUSION: The drugs in the dosages studied may be recommended for first-line treatment of uncomplicated gonococcal urethritis in males in Singapore. However, the emergence of bacterial resistance to the fluoroquinolones in the literature calls for vigilance in the monitoring of antimicrobial susceptibility [corrected].

4-Quinolones↗
PubMed1992

Diffusion of tosufloxacin into prostatic tissue.

The diffusion of tosufloxacin (TFLX) into the prostatic tissue was studied in 25 patients with benign prostatic hypertrophy. TFLX concentrations in the serum and prostatic tissue were measured at scheduled intervals after oral administration of 450 mg of TFLX on the day before surgery, followed by administration of 150 mg of TFLX immediately before surgery. The mean TFLX levels in prostatic tissue (and tissue/serum levels) at 2, 4 and 6 h were 0.35 +/- 0.16 microgram/g (0.93 +/- 0.36) in 7 patients, 0.58 +/- 0.92 microgram/g (1.10 +/- 0.45) in 10 patients and 0.22 +/- 0.09 microgram/g (0.95 +/- 0.45) in 8 patients. The TFLX levels in prostatic tissue exceeded the minimum inhibitory concentration for several pathogenic bacteria detected in the infected prostatic fluid. Therefore, TFLX shows promise as a useful drug in the treatment of bacterial prostatitis and infections developing after prostatic surgery.

4-Quinolones↗
PubMed1992

Quinolone arthropathy--acute toxicity to immature articular cartilage.

A class effect of quinolone antibacterial agents observed during animal toxicity testing is a specific arthropathy (QAP). Despite the growing list of laboratory animals susceptible to QAP and reports of arthralgia in patients treated with quinolones, the potential for QAP development in humans remains unknown. This review discusses current concepts in the biology of articular cartilage and how these concepts elucidate QAP pathogenesis. Biomechanical forces within synovial joints and toxicokinetic properties of quinolones contribute to QAP induction. Since a limited number of mechanistic pathways exist for acute articular damage, QAP may serve as a research tool to probe the pathobiology of injury to articular cartilage.

4-Quinolones↗