Evaluation of indirect susceptibility testing of Mycobacterium tuberculosis to the first- and second-line, and alternative drugs by the newer MB/BacT system
Memórias do Instituto Oswaldo Cruz
In order to evaluate the Organon Teknika MB/BacT system used for testing indirect susceptibility to the alternative drugs ofloxacin (OFLO), amikacin (AMI), and rifabutin (RIF), and to the usual drugs of standard treatment regimes such as rifampin (RMP), isoniazid (INH), pyrazinamide (PZA), streptomycin (SM), ethambutol (EMB), and ethionamide (ETH), cultures of clinical specimens from 117 patients with pulmonary tuberculosis under multidrugresistant investigation, admitted sequentially for
... uentially for examination from 2001 to 2002, were studied. Fifty of the Mycobacterium tuberculosis cultures were inoculated into the gold-standard BACTEC 460 TB (Becton Dickinson) for studying resistance to AMI, RIF, and OFLO, and the remaining 67 were inoculated into Lowenstein Jensen (LJ) medium (the gold standard currently used in Brazil) for studying resistance to RMP, INH, PZA, SM, EMB, and ETH. We observed 100% sensitivity for , , and ; and 100% specificity for , , and compared to the BACTEC system. Comparing the results obtained in LJ we observed 100% sensitivity for RMP (80-100), followed by , and 100% specificity for all drugs tested except for ) at 95% confidence interval. The results showed a high level of accuracy and demonstrated that the fully automated, non-radiometric MB/BacT system is indicated for routine use in susceptibility testing in public health laboratories.