Abstract
The preparation of Frei antigen for diagnosis of lymphogranuloma inguinale has emphasized the need of diagnostic procedures for ruling out the presence of chancroidal infection. Several culture methods have been described for determining the presence of active infection by the Ducrey bacillus, 1 but a skin sensitivity test (Dmelcos) is necessary for detecting previous or latent chancroidal infection. For the latter test it is desirable to obtain the Ducrey bacillus in pure culture and free from other organic matter.
Several methods have been described for the cultivation of the organism. Usually, a relatively large amount of pus from a “bubo” is added to blood agar, or blood media may be inoculated with a small amount of pus from the primary lesion. Teague and Deibert 2 described the use of clotted rabbit blood inactivated for a short time at 55°C., the organism being identified in pure or mixed cultures by the characteristic growth in chains of very small Gram-negative rods resembling streptococci.
The culture method of Teague and Deibert 2 is not suited for production of saline suspensions of the Ducrey organism, and subculture from blood or pus on the usual solid media was sparse or negative in our hands. Other workers have experienced similar difficulties. 3 Commercial preparations (saline suspensions of killed Ducrey bacillus) are available in Europe, but not generally obtainable in this country at the present time. Hence it was desirable to determine conditions which permit growth of the organism on solid media.
The following method gave satisfactory growth with all strains of Ducrey bacillus encountered in the laboratory of the City Hospital. It was found advantageous to employ tubes of clotted, inactivated blood as described by Teague and Deibert 2 for a preliminary culture medium, since such tubes were conveniently handled in the clinic.
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