BACKGROUND AND OBJECTIVESBrucellosis, “undulant fever”, is an infectious disease caused by the bacterial genus Brucella. Health management and timely diagnosis of brucellosis are of great importance for any effective control strategy in humans and animals. This study was aimed at investigating the appropriate concentrations of thionin and fuchsin dyes to identify the biovars of this bacterium .MATERIALS AND METHODS A concentration of ۰.۴% of thionin and fuchsin dyes in distilled water, as well as serum dextrose, tryptic soy agar and Brucell agar were employed as basic media for making colored media.Thionin and basic fuchsin solutions were boiled in a bain-marie for one hour. Then concentrations of ۱۰, ۲۰, and ۴۰ micrograms/ml for thionin dye and ۱۰ and ۲۰ micrograms/ml for fuchsin dye were made based on OIE instructions. Furthermore, the concentration of ۰.۱% dyes in the ۲.۵, ۵, and ۱۰ μg/ml for thionin dye, and ۵ and ۱۰ μg/ml for fuchsin were used for comparison. Horse serum was also considered as a factor stimulating the growth of
Brucella bacteria in environments.RESULTS AND DISCUSSIONThe findings presented in our study have demonstrated that a selective culture medium of
Brucella agar along with serum is the best option for making colored media in the differentiation of
Brucella biovars in classical typing. The percentage of dyes applied in colored media at the rate of ۱۰, ۲۰, and ۴۰ μg/ml for thionin dye and ۱۰ and ۲۰ μg/ml fuchsin dye showed the best accuracy in differentiating different
Brucella biovars. By increasing sterile and inactivated horse serum by ۵%, bacterial growth increased compared to serum-free environments.CONCLUSIONAlthough serum dextrose, tryptic soy agar media have been used as basic media for making colored media in the past, the selective culture media of
Brucella agar with horse serum, showed a high sensitivity for the growth of
Brucella biovars, leading to better growth of Brucella.