Effects of fleroxacin on HeLa cell functions and topoisomerase II.

The effects of fleroxacin and other new 4-quinolones on cellular functions and topoisomerase II of HeLa cells were investigated. The potency of cytotoxicity increased in the order fleroxacin less than nalidixic acid less than ofloxacin less than norfloxacin less than ciprofloxacin. The cytotoxicity was well correlated with inhibitory effects of 4-quinolones on topoisomerase II.

Mutations producing resistance to norfloxacin in Pseudomonas aeruginosa.

Two genetically distinct classes of norfloxacin-resistant Pseudomonas aeruginosa PAO4009 mutants were isolated spontaneously. Two norfloxacin resistance genes, nfxA and nfxB, were mapped hex-9001 and leu-9005 and between pro-9031 and ilv-9023, respectively, on the P. aeruginosa PAO chromosome.

Isolation and characterization of norfloxacin-resistant mutants of Escherichia coli K-12.

We isolated spontaneous mutants from Escherichia coli K-12 with low-level resistance to norfloxacin. These mutants were classified into the following three types on the basis of their properties: (i) NorA appeared to result for mutation in the gyrA locus for the A subunit of DNA gyrase; (ii) NorB showed low-level resistance to quinolones and other antimicrobial agents (e.g.

In vitro and in vivo antibacterial activity of AM-833, a new quinolone derivative.

AM-833 showed potent activity against members of the family Enterobacteriaceae, Neisseria spp., and Haemophilus influenzae and good activity against staphylococci, Pseudomonas aeruginosa, and Branhamella catarrhalis. Against these bacteria, its activity was roughly comparable to that of norfloxacin and ofloxacin but was slightly less potent than that of ciprofloxacin.

Comparative activities of AM-715 and pipemidic and nalidixic acids against experimentally induced systemic and urinary tract infections.

Dose for dose, AM-715 was at least five times as active as pipemidic acid and nalidixic acid against systemic and urinary bladder-kidney infections in mice.

Structure-activity relationships of antibacterial 6,7- and 7,8-disubstituted 1-alkyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids.

Previous quantitative and qualitative structure-activity studies in antibacterial monosubstituted 1-ethyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids prompted us to synthesize the 6,7,8-polysubstituted compounds. In this paper, the preparation and antibacterial activity of the 6,7- and 7,8-disubstituted compounds and their derivatives are described. Among these compounds, 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)quinoline-3-carboxylic acid (34) possessed many significant activities and was more active than oxolinic acid (84) against Gram-positive and Gram-negative bacteria.

In vitro antibacterial activity of AM-715, a new nalidixic acid analog.

AM-715 [1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid] is a new nalidixic acid analog. AM-715 has a broad spectrum of antibacterial activity against gram-positive and gram-negative bacteria. The antibacterial activity of AM-715 was greater than those of pipemidic acid and nalidixic acid.