TY - JOUR T1 - Modification of auramine O fluorescence stain for differential detection of mycobacterium tuberculosis and mycobacteria other than tuberculosis (MOTT) JF - European Respiratory Journal JO - Eur Respir J VL - 40 IS - Suppl 56 SP - P1410 AU - Tarig Alnour AU - Harald Hoffmann AU - Sabina Thiel Y1 - 2012/09/01 UR - http://erj.ersjournals.com/content/40/Suppl_56/P1410.abstract N2 - Auramine O fluorescent stain was found to be more sensitive than Ziehl Neelsen stain for screening M. tuberculosis directly in sputum specimens, but it lack specificity due to false positivity obtained by mycobacterium other than tuberculosis (MOTT) and weakly acid fast bacteria (e.g: Nocardia species). The aim of this study was to modify the time of decolorization by 0.5% acid alcohol in order to increase the specificity without affecting the sensitivity of the stain. Smears were prepared from 25 bacterial cultures classified into 4 different groups. Group A comprises Mycobacterium tuberculosis complex, group B comprises 15 Mycobacteria other than tuberculosis (MOTT), group C comprises Nocardia farcinica and group D comprises one Gram positive and one Gram negative bacteria. All smears were stained with Auramine O fluorescence stain (IML-Red, Germany), 6 smears from each bacterial isolates were decolorized by 0.5% acid alcohol for (1 m, 2 m, 3 m, 4 m, 5 m, 10 m) to each smear separately, then all smears were counterstained with K permanganate for 1 m. All group (A) bacterial isolates were showed 100% fluorescence after 10 minutes decolorization time while the fluorescence of group (B) isolates were reduced to 73.3% after 5 minutes decolorization time and to 53.3% after 10 minutes. Group (C) showed weak fluorescence after 1 and 2 minutes which completely decolorized after 3 minutes. In conclusion, Mycobacterium tuberculosis complex was resistant to decolorization with 0.5% acid alcohol for 10 minutes while some MOTT were decolorized when using the same time. ER -