Evaluation of middlebrook 7H11 associated with human or sheep blood for the detection of mycobacterium tuberculosis in sputum samples

Abstract

Objective. To evaluate the diagnostic yield of the media Middlebrook 7H11 combined with human or ovine blood in comparison with the Ogawa solid media for the diagnosis of pulmonary tuberculosis. Material and methods. We evaluated sputum samples of patients with clinical suspicion of pulmonary tuberculosis. The samples were seeded in Middlebrook 7H11 agar associated with human or ovine blood and in Ogawa media. Results. A total of 130 samples were collected. The positivity for M.tuberculosis in Middlebrook 7H11/human blood, Middlebrook 7H11/sheep blood and Ogawa was 45.38%, 46.15% and 43.84% respectively. The mean times for growth for the M. tuberculosis were 12.81± 6.52, 13.07 ± 6.63 and 20.14 ± 6.75 days (p< 0,01 for the comparison of agar based medium versus Ogawa). Conclusions. The combination of Middlebrook 7H11 with sheep or human blood has a comparable diagnostic yield but a shorter growth time than the Ogawa solid media.