Varma-Basil Mandira, Kumar Sujeet, Yadav Jitender, Kumar Nalini, Bose Mridula
Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
Southeast Asian J Trop Med Public Health. 2007 Jan;38(1):111-4.
We report the applicability of testing susceptibility to paranitrobenzoic acid (PNB) directly on clinical samples as a rapid screening assay, to detect M. tuberculosis and differentiate it from non-tuberculous mycobacteria (NTM). One hundred smear positive sputum samples from patients with pulmonary tuberculosis attending the Department of Respiratory Medicine at VP Chest Institute, Delhi, were cultured on Löwenstein Jensen medium with and without 0.5 mg/ml paranitrobenzoic acid. Serial concentrations of known cultures of H37Rv, M. fortuitum, M. scrofulaceum and M. avium were used as controls in the study. After 3 weeks of incubation, growth was observed on all the drug free Löwenstein Jensen slants but none of the slants containing PNB, which inhibited the growth of M. tuberculosis. The cultures were further confirmed to be M. tuberculosis by niacin, nitrate and catalase tests. Direct susceptibility to PNB was thus found to be a simple, cheap and technically feasible method of preliminary identification of M. tuberculosis and its effective differentiation from NTM, which may be adapted for use at Level II laboratories, especially in developing countries.
我们报告了直接在临床样本上检测对对硝基苯甲酸（PNB）的敏感性作为一种快速筛查试验的适用性，以检测结核分枝杆菌并将其与非结核分枝杆菌（NTM）区分开来。从德里VP胸科研究所呼吸内科就诊的肺结核患者中收集了100份涂片阳性痰样本，分别在含和不含0.5 mg/ml对硝基苯甲酸的洛温斯坦-詹森培养基上培养。研究中使用H37Rv、偶然分枝杆菌、瘰疬分枝杆菌和鸟分枝杆菌的已知培养物的系列浓度作为对照。孵育3周后，在所有不含药物的洛温斯坦-詹森斜面上观察到生长，但含PNB的斜面均未生长，PNB抑制了结核分枝杆菌的生长。通过烟酸、硝酸盐和过氧化氢酶试验进一步确认培养物为结核分枝杆菌。因此，对PNB的直接药敏试验被发现是一种简单、廉价且技术上可行的初步鉴定结核分枝杆菌及其与NTM有效区分的方法，可适用于二级实验室，尤其是在发展中国家。
