The activity of gatifloxacin against 308 aerobes and 112 anaerobes isolated from bite wound infections was studied. Gatifloxacin was active at </=0.016 microg/ml against all 148 Pasteurella isolates (eight species and three subspecies) tested and all other aerobes tested, including Actinobacillus-Haemophilus spp., Eikenella corrodens, Neisseria weaveri, Weeksella zoohelcum, staphylococci, and streptococci. Fusobacteria were sometimes resistant. Gatifloxacin MICs at which 90% of the isolates were inhibited were 0. 125 microg/ml against Bacteroides tectum and Prevotella spp., 0.25 microg/ml against Porphyromonas spp., and 0.5 microg/ml against peptostreptococci.