- The performance of the BACTEC FX blood culture system for detecting Brucella bacteremia within the routine one-week incubation period was assessed in a prospective study conducted in an endemic area for B. melitensis in southern Israel. Aerobic vials (BD BACTEC™ Plus Aerobic/F Medium) inoculated with blood specimens obtained from adult patients with a positive Rose-Bengal screening test were monitored for four consecutive weeks and blind subcultures of negative vials were performed on solid media on days 7 and 28. During a 16-month period, a total of 31 of 88 (35.2%) cultures, obtained from 19 of 50 (38.0%) patients, were positive for Brucellamelitensis . The blood culture instrument disclosed 30 of 31 (96.8%) positive vials within 7 days of incubation, and the single positive vial missed by the automated reading was only detected by the blind subculture performed on day 28. It is concluded that the BACTEC FX system is able to detect the vast majority of episodes of Brucella bacteremia within the one-week incubation protocol instituted in most Clinical Microbiology laboratories and without the need for performing blind subcultures of negative vials, enabling early diagnosis and saving labor and incubation time and space.