TY - JOUR
T1 - Simple and rapid differentiation of Mycobacterium tuberculosis H37Ra from M. tuberculosis clinical isolates through two cytochemical tests using neutral red and Nile blue stains
AU - Soto, Carlos Y.
AU - Andreu, Núria
AU - Gibert, Isidre
AU - Luquin, Marina
PY - 2002/8/1
Y1 - 2002/8/1
N2 - The attenuated Mycobacterium tuberculosis strain H37Ra is one of the most commonly used controls for M. tuberculosis identification in the clinical laboratory and is a source of false-positive results for M. tuberculosis as a consequence of cross-contamination. Therefore, the ability to discriminate between H37Ra and real clinical isolates has important public health implications. To date, differentiation of H37Ra from M. tuberculosis clinical isolates is possible only by IS6110 genotyping and spoligotyping. In the 1950s, some authors reported that the virulent strain H37Rv and M. tuberculosis clinical isolates were able to fix basic dyes in their anionic forms, while H37Ra was not. We have studied the different techniques described for M. tuberculosis cytochemical staining and have chosen the best of these, introducing certain modifications in order to increase their discriminative power and reproducibility. We describe cytochemical staining of M. tuberculosis cells with neutral red and Nile blue, which differentiates H37Ra from virulent strains. This method could be used as an easy laboratory tool for distinguishing between H37Ra and real M. tuberculosis clinical isolates.
AB - The attenuated Mycobacterium tuberculosis strain H37Ra is one of the most commonly used controls for M. tuberculosis identification in the clinical laboratory and is a source of false-positive results for M. tuberculosis as a consequence of cross-contamination. Therefore, the ability to discriminate between H37Ra and real clinical isolates has important public health implications. To date, differentiation of H37Ra from M. tuberculosis clinical isolates is possible only by IS6110 genotyping and spoligotyping. In the 1950s, some authors reported that the virulent strain H37Rv and M. tuberculosis clinical isolates were able to fix basic dyes in their anionic forms, while H37Ra was not. We have studied the different techniques described for M. tuberculosis cytochemical staining and have chosen the best of these, introducing certain modifications in order to increase their discriminative power and reproducibility. We describe cytochemical staining of M. tuberculosis cells with neutral red and Nile blue, which differentiates H37Ra from virulent strains. This method could be used as an easy laboratory tool for distinguishing between H37Ra and real M. tuberculosis clinical isolates.
U2 - https://doi.org/10.1128/JCM.40.8.3021-3024.2002
DO - https://doi.org/10.1128/JCM.40.8.3021-3024.2002
M3 - Article
VL - 40
SP - 3021
EP - 3024
JO - Journal of Clinical Microbiology
JF - Journal of Clinical Microbiology
SN - 0095-1137
ER -