Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis

The drug susceptibilities of 105 isolates/strains of Mycobacterium tubercul osis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional a gar proportion method. The agreement rates between the two methods were 99. 0% for streptomyuin, 95.2% for isoniazid and 100% for rifampin. The mean ti mes to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detect ion were 10.8 days (mean) and 21 days respectively. Thus, these data have d emonstrated that the automated, non-radiometric MB/BacT system is an effici ent, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method. (C) 20 01 Elsevier Science Inc. All rights reserved.