Development and evaluation of TUMS medium, a novel biphasic culture medium for isolation of Brucella spp. from patients

Background and objectives: There are limitations in time and technique for isolation of Brucella from patients. We developed a new Brucella culture medium and evaluated its efficiency compared to BACTEC blood culture system and serology. Materials and Methods: A bi-phasic medium containing Urea agar and Brain Heart Infusion was formulated. Appearance of clear red color in liquid phase was the basis of positivity for Brucella. The new medium which is designated as TUMS medium (TUMS refers to Tehran University of Medical Sciences) and BACTEC blood culture vials were inoculated with different concentrations of 20 Brucella strains. The blood samples from 58 suspected patients were tested by both media and serology (Wright and Coombs). Any growth was sub-cultured and suspected colonies were identified by standard methods. Results: The TUMS medium detected more positive samples (100%) than BACTEC (85%) when the organism was suspended at lower concentration (10 CFU). Of 58 blood cultures, 47 (81%) samples tested on TUMS medium (incubation period =4.2 days) and 39 (67.2 %) samples tested on BACTEC (incubation period =3.3 days) were found positive. Conclusion: The TUMS medium was superior to others in detecting the organism from patients with clinical signs or who took medications for >1year. The TUMS medium is easy to prepare and use in endemic areas where resources are limited.