Gliding motility and actinomycin D sensitivity of Fusobacterium nucleatum and other gram-negative rods

Six strains of gram-negative anaerobic fusiform rods (Fusobacterium and Bacteroides spp.), isolated from deep subgingival locations in humans, were examined for (i) gliding motility in slide cultures, (iii) cell densities on nutrient agar surfaces, and (iii) sensitivity to actinomycin D. Known gliding (FBt) and nonmotile (NM) strains of Myxococcus xanthus served as controls for the gliding and cell density experiments. In the present study, three strains of gram-negative fusiforms from the oral cavity, identified as Fusobacterium nucleatum (1a and P-1) and Bacteroides sp. (P-14), demonstrated characteristics similar to the gliding control strain M. xanthus. The only gliding oral strain sensitive to actinomycin D was a Bacteroides sp. (P-14).