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A Multicenter Study of the Microscopic Observation for Detection and Susceptibility (MODS) Test for Diagnosis of Pulmonary Tuberculosis and Tuberculosis Drug Resistance

This prospective, multicenter evaluation of a new diagnostic and drug susceptibility test in a clinical setting  is the continuation of an ongoing collaborative study in Brazil (GRA/JHU) and Honduras (CRA/UAB) evaluating the accuracy and effectiveness of MODS for TB detection and drug susceptibility testing. 

The increase in drug-resistant TB threatens the success of global TB control. There is an urgent need for inexpensive, accurate methods for detection of M. tuberculosis in clinical specimens and for drug susceptibility testing. An inexpensive, efficient liquid culture method (“microscopic observation for detection and susceptibility” or “MODS”) that relies on microscopic detection of early mycobacterial growth was developed (L Caviedes et al, 2000), and validated in our laboratory for isoniazid and rifampin drug susceptibility testing (W Park et al, 2002). 

The overall goal of this project is to prospectively evaluate the performance of MODS for detection of M. tuberculosis and M. tuberculosis drug susceptibility in respiratory specimens obtained from persons undergoing evaluation for pulmonary TB in TB-endemic developing/transitional country settings (Rio de Janeiro, Brazil, and Tegucigalpa, Honduras). 

The study is a continuation of the first large, prospective field trial of MODS for detection of M. tuberculosis and drug resistance in clinical respiratory specimens obtained from pulmonary TB suspects. 

Principal Investigators:  Richard E. Chaisson, MD and  Susan E. Dorman, MD (JHSPH)


  • Afranio L. Kritski, MD, PhD (Hospital Universitario Clementino Fraga Filho of Federal University of Rio de Janeiro, Brazil (HUCFF, UFRJ))
  • Fernanda Mello, MD, PhD (HUCFF, UFRJ)
  • Leila Fonseca, MD, PhD (HUCCF, UFRJ)
  • Monica Andrade, MD (Hospital Raphael de Paula Souza, UFRJ)


Arias M, Mello FCQ, Pavon A, Marsico AG, Alvarado-Galvez C, Rosales S, Pessoa CLC, Perez M, Andrade MK, Kritski AL, Fonseca LS, Chaisson RE, Kimerling ME, Dorman SE. (2007). Clinical evaluation of the microscopic observation drug susceptibility (MODS) assay for detection of tuberculosis. Clin Infect Dis, 44, 674-80.

Caviedes L, Lee TS, Gilman RH, Sheen P, Spellman E, Lee EH, Berg DE, Montenegro-James S. Rapid, efficient detection and drug susceptibility testing of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures. The TB Working Group in Peru.  J Clin Microbiol. 2000 Mar;38(3):1203-8.

Park WG, Bishai WR, Chaisson RE, Dorman SE. Performance of the microscopic observation drug susceptibility assay in drug susceptibility testing for Mycobacterium tuberculosis.  J Clin Microbiol. 2002 Dec;40(2):4750-2.