Antimicrobial activity of gemifloxacin (SB-265805), a newer fluoroquinolone, against clinical isolates of Neisseria gonorrhoeae, including fluoroquinolone-resistant isolates

Antimicrobial activity of gemifloxacin (SB-265805), a newly developed fluor oquinolone, to Japanese isolates of Neisseria gonorrhoeae was compared with those of various fluoroquinolones, including norfloxacin, ciprofloxacin, t osufloxacin, levofloxacin, sparfloxacin, and trovafloxacin. Among the fluor oquinolones tested, gemifloxacin was most active against N. gonorrhoeae iso lates. The MIC90 values of gemifloxacin for 94 N. gonorrhoeae isolated from 1992 through 1993 and 100 isolated from 1996 through 1997 were 0.03 and 0. 125 mu g/ml, respectively. On the other hand, MIC90 Values of the other flu oroquinolone for the 1992-1993 isolates and the 1996-1997 isolates ranged f rom 0.125 to 2 mu g/ml and from 0.5 to 8 mu g/ml, respectively. Gemifloxaci n was also the most potent fluoroquinolone against 31 ciprofloxacin-resista nt isolates with the ciprofloxacin MIC of 1 to 16 mu g/ml, for which the ge mifloxacin MIC50 and MIC90 values were 0.25 and 2 mu g/ml, respectively. Mo reover, the activity of gemifloxacin against fluoroquinolone-resistant gono coccal isolates containing multiple amino acid substitutions in both GyrA a nd ParC proteins was superior to those of the other compounds. (C) 2000 Els evier Science Inc. All rights reserved.