Gemifloxacin (SB-265805) is a potent, novel
fluoroquinolone with broad-spectrum antimicrobial activity. In this study, the efficacy of
gemifloxacin was studied in experimental models of Gram-negative
pyelonephritis (caused by Escherichia coli or Proteus mirabilis) and Gram-positive
wound infection resulting from Streptococcus pyogenes, Staphylococcus epidermidis or Staphylococcus aureus.
Gemifloxacin activity against these pathogens was compared with those of
amoxycillin-
clavulanate,
ciprofloxacin,
cefuroxime,
azithromycin,
trovafloxacin,
grepafloxacin,
levofloxacin and
tosufloxacin. Oral treatment was initiated 1 h after
infection and continued once or twice daily for 3 days. Around 17 h after the end of treatment, animals were killed and the infected kidneys or the skin around the
wound site were excised for the enumeration of viable bacteria. In the
pyelonephritis model (either microorganism),
gemifloxacin reduced bacterial numbers significantly (P < 0.01) compared with no treatment. No comparator agent had a greater effect than
gemifloxacin. Notably,
grepafloxacin and
azithromycin were significantly less effective (P < 0.01) than
gemifloxacin against E. coli
pyelonephritis, and
amoxycillin-
clavulanate,
azithromycin and
trovafloxacin were inferior (P < 0.01) against P. mirabilis
infection. In the S. pyogenes
wound infection model,
gemifloxacin,
amoxycillin-
clavulanate,
cefuroxime and
azithromycin reduced bacterial numbers significantly compared with controls (P < 0.01). Results for the comparator
quinolones were not significantly different from untreated controls (P > 0.05).
Gemifloxacin was also effective against
staphylococcal infection, as were
grepafloxacin and
levofloxacin, while
ciprofloxacin,
trovafloxacin and
tosufloxacin were significantly less effective against these pathogens than
gemifloxacin (P < 0.01). No comparator agent had greater activity than
gemifloxacin against S. pyogenes or S. aureus
infections. These data demonstrate the potential benefit of
gemifloxacin in the treatment of Gram-negative
urinary tract infection and Gram-positive skin and
soft tissue infection.