Activities of gemifloxacin and five other antimicrobial agents against Listeria monocytogenes and coryneform bacteria isolated from clinical samples

The in vitro activities of gemifloxacin, ciprofloxacin, ampicillin, doxycyc line, gentamicin, and vancomycin were evaluated against 15 Listeria monocyt ogenes strains and 205 coryneform bacteria isolated from clinical samples. The percentages of strains inhibited by gemifloxacin at 0.5 mug/ml were 100 % (L. monocytogenes), 93.3% (Brevibacterium spp.), 90% (Corynebacterium min utissimum), 42.5% (Corynebacterium amycolatum), 20% (Corynebacterium striat um), 12.5% (Corynebacterium jeikeium), and 10% (Corynebacterium urealyticum ). One hundred percent of the L. monocytogenes strains were inhibited by 0. 25 mug of gemifloxacin per mi, whereas 0% of the strains: were inhibited by 0.25 mug of ciprofloxacin per mi. Vancomycin at 2 mug/ml inhibited all str ains. Doxycycline and gentamicin at 4 mug/ml inhibited 94 and 49% of the st rains, respectively, while ampicillin at 0.5, 2, and 8 mug/ml inhibited 24, 61, and 66% of the strains, respectively. It is concluded that gemifloxaci n shows good in vitro activity against L. monocytogenes and coryneform bact eria except C. jeikeium and C. urealyticum.