Rapid molecular detection of tuberculosis and rifampin resistance.

BACKGROUND Global control of tuberculosis is hampered by slow, insensitive diagnostic methods, particularly for the detection of drug-resistant forms and in patients with human immunodeficiency virus infection. Early detection is essential to reduce the death rate and interrupt transmission, but the complexity and infrastructure needs of sensitive methods limit their accessibility and effect. METHODS We assessed the performance of Xpert MTB/RIF, an automated molecular test for Mycobacterium tuberculosis (MTB) and resistance to rifampin (RIF), with fully integrated sample processing in 1730 patients with suspected drug-sensitive or multidrug-resistant pulmonary tuberculosis. Eligible patients in Peru, Azerbaijan, South Africa, and India provided three sputum specimens each. Two specimens were processed with N-acetyl-L-cysteine and sodium hydroxide before microscopy, solid and liquid culture, and the MTB/RIF test, and one specimen was used for direct testing with microscopy and the MTB/RIF test. RESULTS Among culture-positive patients, a single, direct MTB/RIF test identified 551 of 561 patients with smear-positive tuberculosis (98.2%) and 124 of 171 with smear-negative tuberculosis (72.5%). The test was specific in 604 of 609 patients without tuberculosis (99.2%). Among patients with smear-negative, culture-positive tuberculosis, the addition of a second MTB/RIF test increased sensitivity by 12.6 percentage points and a third by 5.1 percentage points, to a total of 90.2%. As compared with phenotypic drug-susceptibility testing, MTB/RIF testing correctly identified 200 of 205 patients (97.6%) with rifampin-resistant bacteria and 504 of 514 (98.1%) with rifampin-sensitive bacteria. Sequencing resolved all but two cases in favor of the MTB/RIF assay. CONCLUSIONS The MTB/RIF test provided sensitive detection of tuberculosis and rifampin resistance directly from untreated sputum in less than 2 hours with minimal hands-on time. (Funded by the Foundation for Innovative New Diagnostics.)

[1]  P. V. van Helden,et al.  A Threshold Value for the Time Delay to TB Diagnosis , 2007, PloS one.

[2]  M. Perkins,et al.  Containment of Bioaerosol Infection Risk by the Xpert MTB/RIF Assay and Its Applicability to Point-of-Care Settings , 2010, Journal of Clinical Microbiology.

[3]  R. Urbanczik,et al.  Scaling up tuberculosis culture services: a precautionary note. , 2009, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[4]  Amalio Telenti,et al.  Molecular beacon sequence analysis for detecting drug resistance in Mycobacterium tuberculosis , 1998, Nature Biotechnology.

[5]  S. Siddiqi,et al.  MGIT procedure manual for BACTEC MGIT 960 TB System , 2006 .

[6]  J. Palomino.  Molecular detection, identification and drug resistance detection in Mycobacterium tuberculosis. , 2009, FEMS immunology and medical microbiology.

[7]  Irene Ayakaka,et al.  Rapid Detection of Mycobacterium tuberculosis and Rifampin Resistance by Use of On-Demand, Near-Patient Technology , 2009, Journal of Clinical Microbiology.

[8]  David Moher,et al.  Towards complete and accurate reporting of studies of diagnostic accuracy: The STARD Initiative. , 2003, Radiology.

[9]  Sonya S. Shin,et al.  The dilemma of MDR-TB in the global era. , 1998, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[10]  S. S. Olmsted,et al.  Requirements for high impact diagnostics in the developing world , 2006, Nature.

[11]  A. Agresti,et al.  Approximate is Better than “Exact” for Interval Estimation of Binomial Proportions , 1998 .

[12]  J. Kop,et al.  Evaluation of the Analytical Performance of the Xpert MTB/RIF Assay , 2010, Journal of Clinical Microbiology.

[13]  D. Havlir,et al.  Opportunities and challenges for HIV care in overlapping HIV and TB epidemics. , 2008, JAMA.

[14]  D. Enarson,et al.  XDR tuberculosis: an indicator of public-health negligence , 2006, The Lancet.

[15]  C A Gatsonis,et al.  Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative. , 2003, Clinical radiology.

[16]  C. Dolea,et al.  World Health Organization , 1949, International Organization.

[17]  William A. Mcmillan,et al.  Technology for automated, rapid, and quantitative PCR or reverse transcription-PCR clinical testing. , 2005, Clinical chemistry.

[18]  S. Rüsch-Gerdes,et al.  Application of the Capilia TB assay for culture confirmation of Mycobacterium tuberculosis complex isolates. , 2005, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[19]  K Y Liang,et al.  Longitudinal data analysis for discrete and continuous outcomes. , 1986, Biometrics.

[20]  Paul Nunn,et al.  Diagnosis of smear-negative pulmonary tuberculosis in people with HIV infection or AIDS in resource-constrained settings: informing urgent policy changes , 2007, The Lancet.

[21]  F. Kramer,et al.  Detection of Rifampin Resistance inMycobacterium tuberculosis in a Single Tube with Molecular Beacons , 2001, Journal of Clinical Microbiology.

[22]  M. Perkins,et al.  Facing the crisis: improving the diagnosis of tuberculosis in the HIV era. , 2007, The Journal of infectious diseases.

[23]  Sonya S. Shin,et al.  Timely diagnosis of MDR-TB under program conditions: is rapid drug susceptibility testing sufficient? , 2006, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[24]  J. Mcclatchy,et al.  The 7H11 medium for the cultivation of mycobacteria. , 1968, The American review of respiratory disease.