Clinical Evaluation of the Microscopic-Observation Drug-Susceptibility Assay for Detection of Tuberculosis

Arias, M S; Mello, Fernanda C. Q.; Pavón, Ada; Marsico, Anna Grazia; Alvarado-Gálvez, Carlos; Rosales, Senia; Pessôa, Carlos Leonardo Carvalho; Pérez, Melly; Andrade, Mônica Kramer de Noronha; Kritski, Afrânio Lineu; Fonseca, Leila S.; Chaisson, Richard E.; Kimerling, Michael E.; Dorman, Susan E.

doi:10.1086/511639

Cited by 66 publications

(49 citation statements)

References 6 publications

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“…Staining with the auramine and Ziehl-Neelsen techniques for acid-fast bacilli was performed, and the presence of acid-fast bacilli was noted and quantified (17). Culture was performed using Lowenstein-Jensen medium (17) and MODS (microscopic observation drug susceptibility) broth culture, as described previously (2,5,26,27,29,31), with direct drug susceptibility testing. For positive cultures, the M. tuberculosis isolates were then subjected to indirect drug susceptibility testing using the colorimetric tetrazolium microplate assay, as described previously (4).…”

Section: Patient Recruitmentmentioning

confidence: 99%

Evaluation of Molecular Tools for Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Stool Specimens from Patients with Pulmonary Tuberculosis

et al. 2010

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Pulmonary tuberculosis diagnosis is difficult when patients cannot produce sputum. Most sputum is swallowed, and tuberculosis DNA can survive intestinal transit. We therefore evaluated molecular testing of stool specimens for detecting tuberculosis originating from the lungs. Paired stool and sputum samples (n ‫؍‬ 159) were collected from 89 patients with pulmonary tuberculosis. Control stool samples (n ‫؍‬ 47) were collected from patients without tuberculosis symptoms. Two techniques for DNA extraction from stool samples were compared, and the diagnostic accuracy of the PCR in stool was compared with the accuracy of sputum testing by PCR, microscopy, and culture. A heminested IS6110-PCR was used for tuberculosis detection, and IS6110-PCR-positive stool samples then underwent rifampin sensitivity testing by universal heteroduplex generator PCR (heteroduplex-PCR) assay. For newly diagnosed pulmonary tuberculosis patients, stool IS6110-PCR had 86% sensitivity and 100% specificity compared with results obtained by sputum culture, and stool PCR had similar sensitivities for HIV-positive and HIV-negative patients (P ‫؍‬ 0.3). DNA extraction with commercially available spin columns yielded greater stool PCR sensitivity than DNA extraction with the in-house Chelex technique (P ‫؍‬ 0.007). Stool heteroduplex-PCR had 98% agreement with the sputum culture determinations of rifampin resistance and multidrug resistance. Tuberculosis detection and drug susceptibility testing by stool PCR took 1 to 2 days compared with an average of 9 weeks to obain those results by traditional culture-based testing. Stool PCR was more sensitive than sputum microscopy and remained positive for most patients for more than 1 week of treatment. In conclusion, stool PCR is a sensitive, specific, and rapid technique for the diagnosis and drug susceptibility testing of pulmonary tuberculosis and should be considered when sputum samples are unavailable.

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Section: Patient Recruitmentmentioning

confidence: 99%

Evaluation of Molecular Tools for Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Stool Specimens from Patients with Pulmonary Tuberculosis

et al. 2010

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“…The microscopic observation drug susceptibility (MODS) assay is a relatively low-cost, simple liquid culture method that relies on the microscopic detection of cording growth that is characteristic of Mycobacterium tuberculosis (1,3,6,7,8). Potential advantages of the MODS method are relatively rapid mycobacterial growth in liquid media and reliance on microscopy skills similar to those used for smear microscopy.…”

Section: It Is Estimated That Approximately 424000 Cases Of Multidrumentioning

confidence: 99%

Clinical Evaluation of the Microscopic Observation Drug Susceptibility Assay for Detection of Mycobacterium tuberculosis Resistance to Isoniazid or Rifampin

Mello

Arias

Rosales³

et al. 2007

J Clin Microbiol

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“…Recent evaluations of a novel diagnostic test for TB, the microscopic observation drug susceptibility assay (MODS), have shown it to be economical and rapid, with a turnaround time of 7 days, making it ideal for use in high-burden, lowresource settings (2,3,14). MODS has been shown effective in the identification of TB in HIV-infected patients (2, 18).…”

Section: The Microscopic Observation Drug Susceptibility Assay (Mods)mentioning

confidence: 99%

“…MODS has been shown effective in the identification of TB in HIV-infected patients (2,18). The increasing number of HIV-positive pulmonary TB suspects presenting to Pham Ngoc Thach Hospital, a referral TB hospital in the south of Vietnam, has led to an urgent need for a rapid and sensitive test to detect TB for this population.…”

Section: The Microscopic Observation Drug Susceptibility Assay (Mods)mentioning

confidence: 99%

“…Rapid molecular line-probe assays, also endorsed for use in lowresource settings by the WHO (28), allow simultaneous identification of Mycobacterium tuberculosis and resistance to rifampin or isoniazid but are currently only recommended for smear-positive samples and positive cultures. In addition, they are expensive and require molecular expertise, which is often not available in low-resource settings.Recent evaluations of a novel diagnostic test for TB, the microscopic observation drug susceptibility assay (MODS), have shown it to be economical and rapid, with a turnaround time of 7 days, making it ideal for use in high-burden, lowresource settings (2,3,14). MODS has been shown effective in the identification of TB in HIV-infected patients (2, 18).…”

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Diagnosis of Pulmonary Tuberculosis in HIV-Positive Patients by Microscopic Observation Drug Susceptibility Assay

Hà

Lan²,

Kiet

et al. 2010

J Clin Microbiol

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The microscopic observation drug susceptibility assay (MODS) is a novel and promising test for the early diagnosis of tuberculosis (TB). We evaluated the MODS assay for the early diagnosis of TB in HIV-positive patients presenting to Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases in southern Vietnam.A total of 738 consecutive sputum samples collected from 307 HIV-positive individuals suspected of TB were tested by smear, MODS, and the mycobacteria growth indicator tube method (MGIT). The diagnostic sensitivity and specificity of MODS compared to the microbiological gold standard (either smear or MGIT) were 87 and 93%, respectively. The sensitivities of smear, MODS, and MGIT were 57, 71, and 75%, respectively, against clinical gold standard (MODS versus smear, P < 0.001; MODS versus MGIT, P ‫؍‬ 0.03). The clinical gold standard was defined as patients who had a clinical examination and treatment consistent with TB, with or without microbiological confirmation. For the diagnosis of smear-negative patients, the sensitivities of MODS and MGIT were 38 and 45%, respectively (P ‫؍‬ 0.08). The median times to detection using MODS and MGIT were 8 and 11 days, respectively, and they were 11 and 17 days, respectively, for smear-negative samples. The original bacterial/fungal contamination rate of MODS was 1.1%, while it was 2.6% for MGIT. The crosscontamination rate of MODS was 4.7%. In conclusion, MODS is a sensitive, specific, and rapid test that is appropriate for the detection of HIV-associated TB; its cost and ease of use make it particularly useful in resource-limited settings.It is estimated by the World Health Organization (WHO) that there were 9.4 million new cases of tuberculosis (TB) in 2008 (24). Of these, 1.4 million (15%) were in HIV-positive patients, and 23% of all HIV-related deaths are estimated to be attributable to TB (23).Vietnam is a high-TB-burden country with steeply rising rates of HIV-TB coinfection (21); 8.1% of newly diagnosed TB patients are now HIV infected (24). These cases are the most urgently in need of diagnosis because they have the highest morbidity and mortality, and yet the diagnosis of TB among HIV-infected individuals is difficult. Screening algorithms based on clinical symptoms alone show high sensitivity but low specificity (5, 25). The microscopy smear method, while simple, specific, and widely available in high-burden settings, has particularly low sensitivity in HIV-infected patients and cannot be used to rule out a diagnosis of TB (13,20). Microbiological confirmation remains desirable and allows investigation of drug susceptibility profiles. Commercial rapid liquid culture techniques have been endorsed by the WHO (27), show higher sensitivity, and are more rapid than traditional solid-mediumbased techniques such as Lowenstein-Jensen culture. However, their high cost and biosafety infrastructure requirements limit their applicability in many high-burden settings. Rapid molecular line-probe assays, also endorsed for use in lowresource settings by the WHO (28), allo...

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Clinical Evaluation of the Microscopic-Observation Drug-Susceptibility Assay for Detection of Tuberculosis

Abstract: The MODS assay is a relatively simple test whose good performance characteristics for detection of pulmonary tuberculosis may make it suitable for resource-limited environments.

Cited by 66 publications

References 6 publications

Evaluation of Molecular Tools for Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Stool Specimens from Patients with Pulmonary Tuberculosis

Evaluation of Molecular Tools for Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Stool Specimens from Patients with Pulmonary Tuberculosis

Clinical Evaluation of the Microscopic Observation Drug Susceptibility Assay for Detection of Mycobacterium tuberculosis Resistance to Isoniazid or Rifampin

Diagnosis of Pulmonary Tuberculosis in HIV-Positive Patients by Microscopic Observation Drug Susceptibility Assay

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