Identification of dye-sensitive strains of Brucella melitensis

Strains of Brucella melitensis biovars 1, 2, and 3 isolated in India, Italy, Kuwait, Saudi Arabia, the Federal Republic of Germany, and Zimbabwe were inhibited by thionin (20 micrograms/ml) but not by basic fuchsin (20 micrograms/ml) or safranin O (200 micrograms/ml). In other respects the strains were typical of their species and biovars. The existence of dye-sensitive strains of B. melitensis suggests that the present system of classification requires modification.