IN-VITRO AND IN-VIVO ACTIVITIES OF AM-1155, A NEW FLUOROQUINOLONE, AGAINST CHLAMYDIA SPP

The in vitro and in vivo activities of AM-1155, a new quinolone, again st Chlamydia spp. were investigated, The MIC of AM-1155 for 10 standar d strains of different Chlamydia spp. and 25 wild-type strains of Chla mydia pneumoniae isolated in Japan, which were morphologically differe nt from clinical isolates from the United States, ranged from 0.063 to 0.125 mu g/ml. Its activity was almost the same as those of sparfloxa cin and tosufloxacin and was 4 and 16 times superior to those of levof loxacin and ciprofloxacin, respectively, but lower than those of clari thromycin and minocycline (range for each, 0.016 to 0.031 mu g/ml). Th e minimal chlamydiacidal concentration of AM-1155 ranged from 0.063 to 0.125 mu g/ml, while those of clarithromycin and minocycline ranged f rom 0.016 to 0.031 mu g/ml and 0.016 to 0.063 mu g/ml, respectively, T he therapeutic effect of a 7-day course of AM-1155 at doses of 5 and 1 0 mg/kg of body weight administered orally twice daily to mice with ex perimental Chlamydia psittaci pneumonia was excellent, with a 100% sur vival rate at 21 days after infection, The efficacy was equal to those of clarithromycin and minocycline and higher than those of ciprofloxa cin and ofloxacin.