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OBJECTIVES To evaluate the performance of three rapid low-cost methods for the detection of resistance to first-line drugs in Mycobacterium tuberculosis. METHODS One hundred M. tuberculosis clinical isolates were tested by the nitrate reductase assay (NRA), the MTT test and the resazurin microtitre assay (REMA), and the results compared with those(More)
Tuberculosis (TB) remains one of the major causes of death from a single infectious agent worldwide. Of great concern for TB control is the emergence of drug resistance. Since there is no cure for some multidrug-resistant strains of Mycobacterium tuberculosis, there is concern that they may spread around the world, stressing the need for additional control(More)
The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 10(2)/ml to 10(5)/ml, with the highest counts in sewage-contaminated areas and irrigation(More)
The effect of low oxygen concentration on the growth of 15 strains of Mycobacterium ulcerans was evaluated in the BACTEC system. Reduced oxygen tension enhanced the growth of M. ulcerans, suggesting that this organism has a preference for microaerobic environments. Application of this observation may improve rates of isolation of M. ulcerans in primary(More)
OBJECTIVES With the spread of multidrug-resistant tuberculosis (MDR-TB) there is increasing demand for new accurate and cost-effective tools for rapid drug susceptibility testing (DST), particularly for developing countries. The reference standard method used today for DST is very slow and cumbersome. Colorimetric assays using redox indicators have been(More)
Tuberculosis (TB) is a serious public health problem worldwide. Its situation is worsened by the presence of multidrug resistant (MDR) strains of Mycobacterium tuberculosis, the causative agent of the disease. In recent years, even more serious forms of drug resistance have been reported. A better knowledge of the mechanisms of drug resistance of M.(More)
Tuberculosis (TB) remains one of the leading public health problems worldwide. Declared as a global emergency in 1993 by the WHO, its control is hampered by the emergence of multidrug resistance (MDR), defined as resistance to at least rifampicin and isoniazid, two key drugs in the treatment of the disease. More recently, severe forms of drug resistance(More)
BACKGROUND Multidrug resistant tuberculosis (MDR-TB) is a major threat for global tuberculosis control. The W-Beijing Mycobacterium tuberculosis genotype has been associated with drug resistance. Elucidation of the mechanisms underlying this epidemiological finding may have an important role in the control of MDR-TB. The aim of this study was to evaluate(More)
OBJECTIVES To evaluate nitrate reductase assay (NRA) efficacy for streptomycin, isoniazid, rifampicin and ethambutol susceptibility testing of Mycobacterium tuberculosis strains. METHODS Results were generated by three laboratories: the Instituto Adolfo Lutz (IAL) Mycobacteria Reference Laboratory and two IAL Regional Laboratories in Santo André and(More)
OBJECTIVES The purpose of this study was to develop and assess a rapid method for pyrazinamide resistance detection in Mycobacterium tuberculosis using nicotinamide in a colorimetric resazurin assay. METHODS We have tested M. tuberculosis isolates using nicotinamide in a 96-well format with the redox indicator resazurin (REMA) and compared results using(More)