AM-1155 is a new
quinolone with a wide spectrum of antibacterial activity against various bacteria including anaerobes and Mycoplasma pneumoniae.
AM-1155 was 2- to 16-fold more active than
ciprofloxacin and
ofloxacin against Staphylococcus aureus including methicillin-resistant strains, Staphylococcus epidermidis, Streptococcus pneumoniae, and Enterococcus faecalis; its MICs for 90% of strains tested were 0.10 to 0.78 micrograms/ml. The activity of
AM-1155 was comparable to that of
ciprofloxacin against members of the family Enterobacteriaceae, Branhamella catarrhalis, Haemophilus influenzae, and Neisseria gonorrhoeae, but was fourfold less than that of
ciprofloxacin against Pseudomonas aeruginosa. Against Xanthomonas maltophilia, Acinetobacter calcoaceticus, and Campylobacter jejuni,
AM-1155 was two- to fourfold more active than
ciprofloxacin. At a concentration of 1.56 micrograms/ml,
AM-1155 inhibited 90% of Bacteroides fragilis strains tested; its activity was 8- to 10-fold higher than those of
ofloxacin and
ciprofloxacin. Development of resistance to
AM-1155 in S. aureus and S. epidermidis occurred at a lower frequency than did that to
ciprofloxacin after eight transfers in the presence of
drug. In the oral treatment of mouse systemic
infections,
AM-1155 was four- to eightfold more effective than
ciprofloxacin against gram-positive cocci and was as active as
ciprofloxacin against gram-negative rods. The efficacy of an oral or a subcutaneous dose of
AM-1155 was two- to fivefold greater than that of
ofloxacin. Against experimental
pneumonia with Klebsiella pneumoniae and P. aeruginosa,
AM-1155 was two- to fourfold more active than
ciprofloxacin and
ofloxacin.
AM-1155 also had good efficacy against mouse ascending
urinary tract infections with Escherichia coli and P. aeruginosa. These results suggest that
AM-1155 may be a potent
antibacterial agent applicable to various
infections.