TY - JOUR
T1 - Detection and quantification of mycobacterium tuberculosis in the sputum of culture-negative HIV-infected pulmonary tuberculosis suspects
T2 - A proof-of-concept study
AU - Madico, Guillermo
AU - Mpeirwe, Moses
AU - White, Laura
AU - Vinhas, Solange
AU - Orr, Beverley
AU - Orikiriza, Patrick
AU - Miller, Nancy S.
AU - Gaeddert, Mary
AU - Mwanga-Amumpaire, Juliet
AU - Palaci, Moises
AU - Kreiswirth, Barry
AU - Straight, Joe
AU - Dietze, Reynaldo
AU - Boum, Yap
AU - Jones-López, Edward C.
N1 - Publisher Copyright:
© 2016 Madico et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - Rationale: Rapid diagnosis of pulmonary tuberculosis (TB) is critical for timely initiation of treatment and interruption of transmission. Yet, despite recent advances, many patients remain undiagnosed. Culture, usually considered the most sensitive diagnostic method, is sub-optimal for paucibacillary disease. Methods: We evaluated the Totally Optimized PCR (TOP) TB assay, a new molecular test that we hypothesize is more sensitive than culture. After pre-clinical studies, we estimated TOP's per-patient sensitivity and specificity in a convenience sample of 261 HIV-infected pulmonary TB suspects enrolled into a TB diagnostic study in Mbarara, Uganda against MGIT culture, Xpert MTB/RIF and a composite reference standard. We validated results with a confirmatory PCR used for sequencing M. tuberculosis. Measurements and Results: Using culture as reference, TOP had 100% sensitivity but 35% specificity. Against a composite reference standard, the sensitivity of culture (27%) and Xpert MTB/RIF (27%) was lower than TOP (99%), with similar specificity (100%, 98% and 87%, respectively). In unadjusted analyses, culture-negative/TOP-positive patients were more likely to be older (P<0001), female (P<0001), have salivary sputum (P = 005), sputum smear-negative (P<0.001) and less advanced disease on chest radiograph (P = 0.05). M. tuberculosis genotypes identified in sputum by DNA sequencing exhibit differential growth in culture. Conclusions: These findings suggest that the TOP TB assay is accurately detecting M. tuberculosis DNA in the sputum of culture-negative tuberculosis suspects. Our results require prospective validation with clinical outcomes. If the operating characteristics of the TOP assay are confirmed in future studies, it will be justified as a "TB rule out" test.
AB - Rationale: Rapid diagnosis of pulmonary tuberculosis (TB) is critical for timely initiation of treatment and interruption of transmission. Yet, despite recent advances, many patients remain undiagnosed. Culture, usually considered the most sensitive diagnostic method, is sub-optimal for paucibacillary disease. Methods: We evaluated the Totally Optimized PCR (TOP) TB assay, a new molecular test that we hypothesize is more sensitive than culture. After pre-clinical studies, we estimated TOP's per-patient sensitivity and specificity in a convenience sample of 261 HIV-infected pulmonary TB suspects enrolled into a TB diagnostic study in Mbarara, Uganda against MGIT culture, Xpert MTB/RIF and a composite reference standard. We validated results with a confirmatory PCR used for sequencing M. tuberculosis. Measurements and Results: Using culture as reference, TOP had 100% sensitivity but 35% specificity. Against a composite reference standard, the sensitivity of culture (27%) and Xpert MTB/RIF (27%) was lower than TOP (99%), with similar specificity (100%, 98% and 87%, respectively). In unadjusted analyses, culture-negative/TOP-positive patients were more likely to be older (P<0001), female (P<0001), have salivary sputum (P = 005), sputum smear-negative (P<0.001) and less advanced disease on chest radiograph (P = 0.05). M. tuberculosis genotypes identified in sputum by DNA sequencing exhibit differential growth in culture. Conclusions: These findings suggest that the TOP TB assay is accurately detecting M. tuberculosis DNA in the sputum of culture-negative tuberculosis suspects. Our results require prospective validation with clinical outcomes. If the operating characteristics of the TOP assay are confirmed in future studies, it will be justified as a "TB rule out" test.
UR - http://www.scopus.com/inward/record.url?scp=84979268175&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84979268175&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0158371
DO - 10.1371/journal.pone.0158371
M3 - Article
C2 - 27391604
AN - SCOPUS:84979268175
SN - 1932-6203
VL - 11
JO - PloS one
JF - PloS one
IS - 7
M1 - e0158371
ER -