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

Mello, Fernanda C. Q.; Arias, M S; Rosales, Senia; Marsico, Anna Grazia; Pavón, Ada; Alvarado-Gálvez, Carlos; 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:10.1128/jcm.00580-07

Cited by 25 publications

(18 citation statements)

References 6 publications

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“…This is a limitation of this technique. Recently, Mello et al found that the sensitivity of DST-MODS for detection of INH resistant isolates increased to 96.7% if INH 0.1 μg/ml was used for the MODS assay [32]; and a similar conclusion was reported from a meta-analysis [8]. This review supported the use of INH 0.1 μg/ml for DST-MODS and our data also supports the conclusion that the use of 0.4 μg/ml reduces sensitivity in comparison with conventional DST.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant Tuberculosis in Viet Nam

Hà

Lan²,

Wolbers

et al. 2012

BMC Infect Dis

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Background Early diagnosis of tuberculosis (TB) and multidrug resistant tuberculosis (MDR TB) is important for the elimination of TB. We evaluated the microscopic observation drug susceptibility (MODS) assay as a direct rapid drug susceptibility testing (DST) method for MDR-TB screening in sputum samples Methods All adult TB suspects, who were newly presenting to Pham Ngoc Thach Hospital from August to November 2008 were enrolled into the study. Processed sputum samples were used for DST by MODS (DST-MODS) (Rifampicin (RIF) 1 μg/ml and Isoniazid (INH) 0.4 μg/ml), MGIT culture (Mycobacterial Growth Indicator Tube) and Lowenstein Jensen (LJ) culture. Cultures positive by either MGIT or LJ were used for proportional DST (DST-LJ) (RIF 40 μg/ml and INH 0.2 μg/ml). DST profiles on MODS and LJ were compared. Discrepant results were resolved by multiplex allele specific PCR (MAS-PCR). Results Seven hundred and nine TB suspects/samples were enrolled into the study, of which 300 samples with DST profiles available from both MODS and DST-LJ were analyzed. Cording in MODS was unable to correctly identify 3 Mycobacteria Other Than Tuberculosis (MOTT) isolates, resulting in 3 false positive TB diagnoses. None of these isolates were identified as MDR-TB by MODS. The sensitivity and specificity of MODS were 72.6% (95%CI: 59.8, 83.1) and 97.9% (95%CI: 95.2, 99.3), respectively for detection of INH resistant isolates, 72.7% (95%CI: 30.9, 93.7) and 99.7% (95%CI: 98.1, 99.9), respectively for detecting RIF resistant isolates and 77.8% (95%CI: 39.9, 97.1) and 99.7% (95%CI: 98.1, 99.9), respectively for detecting MDR isolates. The positive and negative predictive values (PPV and NPV) of DST-MODS were 87.5% (95%CI: 47.3, 99.6) and 99.3% (95%CI: 97.5, 99.9) for detection of MDR isolates; and the agreement between MODS and DST-LJ was 99.0% (kappa: 0.8, P < 0.001) for MDR diagnosis. The low sensitivity of MODS for drug resistance detection was probably due to low bacterial load samples and the high INH concentration (0.4 μg/ml). The low PPV of DST-MODS may be due to the low MDR-TB rate in the study population (3.8%). The turnaround time of DST-MODS was 9 days and 53 days for DST-LJ. Conclusion The DST-MODS technique is rapid with low contamination rates. However, the sensitivity of DST-MODS for detection of INH and RIF resistance in this study was lower than reported from other settings.

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Section: Discussionmentioning

confidence: 99%

Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant Tuberculosis in Viet Nam

Hà

Lan²,

Wolbers

et al. 2012

BMC Infect Dis

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“…It also has a low cost and allows simultaneous detection of the bacilli and the incorporation of drugs for the susceptibility testing. The method is based on the principle that M. tuberculosis grows faster in a liquid medium, and its characteristic growth 'cording formation' can be observed through an inverted light microscope [12][13][14][15]. Several studies have used the MODS to determine susceptibility to isoniazid and rifampicin [12,13,[15][16][17], and it seems to be reliable as compared with the reference method.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the microscopic observation drug susceptibility assay for detection of Mycobacterium tuberculosis resistance to pyrazinamide

Ghiraldi¹,

Campanerut

Spositto

et al. 2011

Clinical Microbiology and Infection

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The microscopic observation drug susceptibility assay (MODS) was evaluated to determine susceptibility to pyrazinamide in Mycobacterium tuberculosis, and compared with the broth microdilution method (BMM), absolute concentration method (ACM), and pyrazinamidase (PZase) determination. We tested 34 M. tuberculosis clinical isolates (24 sensitive and eight resistant to pyrazinamide) and the control strains M. tuberculosis H37Rv (ATCC 27294) and Mycobacterium bovis AN5. The MODS, BMM, ACM and PZase determination provided results in average times of 6, 18, 28 and 7 days, respectively. All methods showed excellent sensitivity and specificity (p <0.05). Of the methods studied, the MODS proved to be faster, efficient, inexpensive, and easy to perform. However, additional studies evaluating the MODS in differentiating pyrazinamide-resistant and pyrazinamide-susceptible M. tuberculosis must be conducted with a larger number of clinical isolates.

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“…The MODS assay is a broth microtiter method designed to detect M. tuberculosis complex and to detect resistance to isoniazid and rifampin (Moore, 2006;Mello, 2007;Ha, 2010). The method uses standard microtiter plates and other materials that are readily available in larger diagnostic laboratories.…”

Section: Microscopic Observation Drug Susceptibility (Mods) Assaymentioning

confidence: 99%

Detection of Mycobacterium tuberculosis and Drug Resistance: Opportunies and Challenges in Morocco

Chaoui¹,

Abid²,

Messaoudi³

et al. 2012

Understanding Tuberculosis - Global Experiences and Innovative Approaches to the Diagnosis

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

Cited by 25 publications

References 6 publications

Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant Tuberculosis in Viet Nam

Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant Tuberculosis in Viet Nam

Evaluation of the microscopic observation drug susceptibility assay for detection of Mycobacterium tuberculosis resistance to pyrazinamide

Detection of Mycobacterium tuberculosis and Drug Resistance: Opportunies and Challenges in Morocco

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