In vitro susceptibility of 1021 strains of recent clinical isolates wa
s determined against the new fluoroquionolone CI-990 (PD 131112) and c
ompared with CI-960, ciprofloxacin, fleroxacin, lomefloxacin, norfloxa
cin, pefloxacin. sparfloxacin. and temafloxacin. The minimum inhibitor
y concentrations (MIC) of CI-990 in mg/L required for >90% isolates we
re 0.03-0.5 for members of Enterobacteriaceae. 0.12-2.0 for Pseudomona
s aeruginosa, 0.03-1.0 for Aeromonas hydrophila, 1.0-2.0 for Acinetoba
cter calcoaceticus, 0.5-2.0 for Brucella melitensis, 0.06-1.0 for stap
hylococci, and 1.0-2.0 for enterococci. Its antibacterial activity was
comparable or superior to other fluoroquinolones tested against most
gram-negative and gram-positive bacteria, including enterococci.