A Culture Technique for the Diagnosis of Infections with Dermocystidium marinum Mackin, Owen, and Collier in Oysters

Abstract

D. marinum is a fungus parasite widely distributed in oysters of the Gulf andS. Atlantic coast of the U. S. 5 x 10 mm., pieces of heart, gills, rectum, or mantle are cultured in Difco s fluid thioglycollate rehydrated with sea water, and tubed in 10 ml. amts. Streptomycin and penicillin solns. are added shortly before inoculation to give concns. of 250 U./ml. Complete sterility is not necessary. Incubate between 18[degree]-25[degree]C. The spores typically grown from 35[mu] at 18 hrs. to 100[mu] or over after a week, and may be identified directly by inspection. If scanty or small, however, the spores may be identified by a typical change from a faint blue to a deep blue-black after a week cultured as above, but with a 125 aqueous Lugol''s soln. added. This culture technic is less laborious and more certain than attempting to identify the spores in histological sections.