In vitro and in vivo antibacterial activity of AB206, a new naphthyridine derivative

Comparison of the antibacterial in vitro and in vivo activity of ofloxacin (HOE 280 DL 8280) and nalidixic acid analogues

The in vitro and in vivo activity of ofloxacin (DL 8280, HOE 280) was compared with that of other antibacterial compounds. Ofloxacin was found to have a broad antibacterial spectrum which includes both gram-positive and gram-negative aerobic and anaerobic species. Its activity is generally higher than that of pipemidic acid and nalidixic acid. Against staphylococci and streptococci, ofloxacin proved to be more active than norfloxacin. In the case of Enterobacteriaceae and Pseudomonadaceae, ofloxacin and norfloxacin possess comparable activities. Ofloxacin was the most active compound against a number of aerobic isolates which are resistant to cefotaxime and ceftriaxone. Of the compounds compared, ofloxacin was the only one which exhibited reasonable activity against anaerobes. It inhibited all strains of Bacteroides fragilis at a concentration of 3.125 mg/l and the gram-positive anaerobes at 0.5 mg/l. In mice experimentally infected with various gram-positive and gram-negative bacteria, ofloxacin was more active than norfloxacin and pipemidic acid. With the gram-negative pathogens, orally administered ofloxacin was as active as gentamicin used parenterally. We conclude from our studies that ofloxacin could be a valuable therapeutic agent with a variety of indications.

In vitro and in vivo activity of DL-8280, a new oxazine derivative

DL-8280, 9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H- pyrido-(1,2,3-de)1,4-benzoxazine-6-carboxylic acid, is a new nalidixic acid analog with a broad spectrum of antibacterial activity against gram-negative and gram-positive bacteria, including obligate anaerobes. The activity of DL-8280 against Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Neisseria gonorrhoeae, and Clostridium perfringens was roughly comparable to that of norfloxacin and far exceeded that of pipemidic acid and nalidixic acid. DL-8280 had greater activity against Staphylococcus spp., Streptococcus spp., Pseudomonas maltophilia, Acinetobacter spp., and Bacteroides fragilis than did norfloxacin, pipemidic acid, and nalidixic acid. Nalidixic acid-resistant Enterobacteriaceae, ampicillin-resistant gonococci, and clindamycin-resistant obligate anaerobes were also susceptible to DL-8280. The activity of DL-8280 was affected very little by inoculum size, and its action was bactericidal at two times the minimal inhibitory concentrations at most. Administered orally to mice experimentally infected with Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis, Serratia marcescens, or P. aeruginosa, DL-8280 was 2 to 7 times more effective than norfloxacin and 7 to more than 50 times more active than pipemidic acid.