Multicenter in vitro comparative study of fluoroquinolones against 25,129 gram-positive and gram-negative clinical isolates.

In vitro activities of fleroxacin, ciprofloxacin, ofloxacin, and lomefloxacin were evaluated against 25,129 fresh bacterial isolates from 51 US hospital or medical center laboratories, beginning in October of 1990. Susceptibility rates were > or = 85% against most species of Gram-negative bacteria. Notable exceptions were Pseudomonas, Acinetobacter, Xanthomonas, and Providencia.

Dual-action cephalosporins incorporating a 3'-tertiary-amine-linked quinolone.

We have previously reported that linking quinolones to the cephalosporin 3'-position through an ester bond, a carbamate function, or a bond through a quaternary nitrogen produced cephalosporins with a dual mode of antibacterial action. We now describe a new class of dual-action cephalosporins, with greater chemical stability than those previously reported, in which the basic nitrogen of ciprofloxacin is bonded directly to the 3'-cephalosporin position, i.e.

A multicenter study on the comparative in vitro activity of fleroxacin and three other quinolones: an interim report from 27 centers.

A multicenter study was designed to compare the in vitro activity of fleroxacin to that of three other oral quinolones (ciprofloxacin, ofloxacin, and lomefloxacin) against fresh clinical bacterial isolates in hospital or medical center laboratories throughout the United States. Each of the 50 centers was asked to test 500 gram-negative and gram-positive strains using the MicroScan (Baxter) microtiter system. This report includes the results of the study, begun in October 1990, on 12,013 isolates tested in 27 centers.

Dual-action cephalosporins: cephalosporin 3'-quinolone carbamates.

A series of cephalosporins has been prepared in which the 3'-position was linked to the nitrogen of the antibacterial quinolone ciprofloxacin through a carbamate function. Like the ester-linked and quaternary-linked dual-action cephalosporins reported earlier, these carbamate-linked compounds exhibited a broad antibacterial spectrum derived from both cephalosporin-like and quinolone-like activities, suggesting a dual mode of action. Studies to elucidate details of the mechanism of action have been inconclusive.

Dual-action cephalosporins: cephalosporin 3'-quaternary ammonium quinolones.

When cephalosporins exert their biological activity by reacting with bacterial enzymes, opening of the beta-lactam ring can lead to expulsion of the 3'-substituent. A series of cephalosporins was prepared in which antibacterial quinolones were linked to the 3'-position through a quaternary nitrogen. Like the 3'-ester-linked dual-action cephalosporins reported earlier, these compounds demonstrated a broad spectrum of antibacterial activity derived from cephalosporin-like and quinolone-like components, suggesting a dual mode of action.