Drug susceptibility testing of Mycobacterium tuberculosis by a nitrate reductase assay applied directly on microscopy-positive sputum samples

• الحاوية / القاعدة: International Journal of Mycobacteriology
• المؤلفون الرئيسيون: Sana Kammoun, Salma Smaoui, Chema Marouane, Leila Slim, Férièle Messadi-Akrout
• التنسيق: مقال
• اللغة: الإنجليزية
• منشور في: Wolters Kluwer Medknow Publications 2015-01-01
• الموضوعات: Drug resistance; M. tuberculosis; Drug susceptibility testing; Sputum
• الوصول للمادة أونلاين: http://www.ijmyco.org/article.asp?issn=2212-5531;year=2015;volume=4;issue=3;spage=202;epage=206;aulast=Kammoun

Aims and objectives: Current methods for drug susceptibility testing (DST) of Mycobacterium tuberculosis (MTB) are either costly or slow. As the prevalence of multidrug-resistant (MDR) strains increases, the need for fast, reliable, and inexpensive methods is obvious. This study evaluated a rapid colorimetric nitrate reductase assay (NRA) for direct DST of MTB directly from clinical sputum samples. Methods: A total of 111 sputa with positive microscopy results for acid-fast bacilli (AFB) with more than 10 AFB per high-power field were used in the study. The samples were decontaminated using the modified Petroff method. The NRA results were compared with the reference indirect proportion method. Results: The sensitivity and the specificity of the direct NRA were 90% and 97.3%, 92.6% and 98.2%, 52.9% and 100%, and 28.6% and 100% for rifampin, isoniazid, streptomycin, and ethambutol, respectively. The results were in most cases available in 28 days (84.3%). Conclusions: The direct NRA could be used as a rapid, inexpensive, and accurate method to determine rifampin and isoniazid susceptibility directly from sputum. The technique might become a valid alternative to traditional methods, especially in low-income countries.