Isolation and characterization of a new Cytophaga species implicated in a work-related lung disease

A yellow-pigmented, gram-negative, gliding bacterium isolated from an industrial water spray air humidification system was implicated as a causative agent in several occurrences of lung disease with hypersensitivity pneumonitis-like symptoms. The bacterium, designated WF-164, lacked microcysts or fruiting bodies and had a DNA base composition of 34.8 mol% of guanine plus cytosine. Gliding, flexing, nonflagellated cells measuring 0.3 by 3.5 to 8.9 micron were observed by using light and electron microscopy. Tests to determine utilization of selected carbohydrates revealed an amylolitic, chitinoclastic, noncellulytic bacterium. A number of additional biochemical and physiological tests were performed. DNA homology studies detected a 77.8% similarity to Cytophaga aquatilis (ATCC 29551). Comparisons of cellular fatty acid and carbohydrate contents of isolate WF-164 with a Flexibacter sp., several Cytophaga spp., and Flavobacterium reference strains revealed similar patterns to that of C. aquatilis. On the basis of these characteristics, isolate WF-164 was identified as a new Cytophaga sp.