Volume 86, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Tuberculosis (TB) is a leading cause of morbidity and mortality and is frequently complicated by emergence of drug-resistant strains. Diagnosis of TB in developing countries is often based on the relatively insensitive acid-fast staining that does not enable susceptibility profiling. Microscopic observation drug susceptibility assay (MODS) is an inexpensive, simple method that enables rapid TB culture coupled with susceptibility testing. A 3-week MODS training of three Ethiopian laboratory technicians was conducted at Hadassah-Hebrew University Medical Center, Israel. Results of the trainee readings were blindly assessed by an experienced instructor. Two hundred fifty-five (255) trainee culture readings were evaluated throughout the course. The sensitivity and specificity were 75–100% and 31.5–100%, respectively. Multivariate analysis revealed that sensitivity and duration of incubation were positively correlated, although specificity was positively correlated with the length of training. MODS can be reliably performed by laboratory technicians inexperienced in culture techniques in developing countries, with high sensitivity and specificity reached after a brief learning period.


Article metrics loading...

Loading full text...

Full text loading...



  1. World Health Organization, 2010. Global tuberculosis control 2010. Available at: http://www.who.int/tb/publications/global_report/2010. Accessed August 6, 2011.
  2. Frieden TR, Sterling TR, Munsiff SS, Watt CJ, Dye C, , 2003. Tuberculosis. Lancet 362: 887899.
  3. Lönnroth K, Castro KG, Chakaya JM, Chauhan LS, Floyd K, Glaziou P, Raviglione MC, , 2010. Tuberculosis control and elimination 2010–50: cure, care, and social development. Lancet 375: 18141829.[Crossref]
  4. 2007. Reported HIV status of tuberculosis patients-United States, 1993–2005. MMWR Morb Mortal Wkly Rep 56: 11031106.
  5. Cohen GM, , 2007. Access to diagnostics in support of HIV/AIDS and tuberculosis treatment in developing countries. AIDS 21 (Suppl 4): S81S87.[Crossref]
  6. Bock NN, Jensen PA, Miller B, Nardell E, , 2007. Tuberculosis infection control in resource-limited settings in the era of expanding HIV care and treatment. J Infect Dis 196 (Suppl 1): S108S113.[Crossref]
  7. Perkins MD, Cunningham J, , 2007. Facing the crisis: improving the diagnosis of tuberculosis in the HIV era. J Infect Dis 196 (Suppl 1): S15S27.[Crossref]
  8. Habeenzu C, Mitarai S, Lubasi D, Mudenda V, Kantenga T, Mwansa J, Maslow JN, , 2007. Tuberculosis and multidrug resistance in Zambian prisons, 2000–2001. Int J Tuberc Lung Dis 11: 12161220.
  9. Wells CD, Cegielski JP, Nelson LJ, Laserson KF, Holtz TH, Finlay A, Castro KG, Weyer K, , 2007. HIV infection and multidrug-resistant tuberculosis: the perfect storm. J Infect Dis 196 (Suppl 1): S86S107.[Crossref]
  10. Nathanson E, Nunn P, Uplekar M, Floyd K, Jaramillo E, Lönnroth K, Weil D, Raviglione M, , 2010. MDR tuberculosis–critical steps for prevention and control. N Engl J Med 363: 10501058.[Crossref]
  11. World Health Organization, 2010. Multidrug and extensively drug-resistant TB (M/XDR- TB): 2010 global report on surveillance and response. Available at: http://www.who.int/tb/features_archive/m_xdrtb_facts. Accessed August 6, 2011.
  12. World Health Organization, 2010. 2010/2011 Tuberculosis Global Facts. Available at: http://www.who.int/tb/publications/2010/factsheet_tb_2010.pdf. Accessed August 6, 2011.
  13. Fitzgerald DW, Sterling TR, Haas DW, Mandell GL, Bennett JE, Dolin R, , 2009. Mycobacterium tuberculosis . , eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. Seventh edition. Philadelphia, PA: Churchill Livingstone Elsevier, 31293163.
  14. Wilkinson D, De Cock KM, Sturm AW, , 1997. Diagnosing tuberculosis in a resource-poor setting: the value of a trial of antibiotics. Trans R Soc Trop Med Hyg 91: 422424.[Crossref]
  15. Finch D, Beaty CD, , 1997. The utility of a single sputum specimen in the diagnosis of tuberculosis. Comparison between HIV-infected and non-HIV-infected patients. Chest 111: 11741179.[Crossref]
  16. Morse M, Kessler J, Albrecht S, Kim R, Thakur R, Nthobatsang R, Radisowa K, Maunatlala C, Yang W, Macgregor RR, Friedman H, , 2008. Induced sputum improves the diagnosis of pulmonary tuberculosis in hospitalized patients in Gaborone, Botswana. Int J Tuberc Lung Dis 11: 12791285.
  17. Elliott AM, Namaambo K, Allen BW, Luo N, Hayes RJ, Pobee JO, McAdam KP, , 1993. Negative sputum smear results in HIV-positive patients with pulmonary tuberculosis in Lusaka, Zambia. Tuber Lung Dis 74: 191194.[Crossref]
  18. Bassett IV, Wang B, Chetty S, Giddy J, Losina E, Mazibuko M, Bearnot B, Allen J, Walensky RP, Freedberg KA, , 2010. Intensive tuberculosis screening for HIV-infected patients starting antiretroviral therapy in Durban, South Africa. Clin Infect Dis 51: 823829.[Crossref]
  19. Casal M, Gutierrez J, Vaquero M, , 1997. Comparative evaluation of the mycobacteria growth indicator tube with the BACTEC 460 TB system and Lowenstein-Jensen medium for isolation of mycobacteria from clinical specimens. Int J Tuberc Lung Dis 1: 8184.
  20. Boehme CC, Nabeta P, Hillemann D, Nicol MP, Shenai S, Krapp F, Allen J, Tahirli R, Blakemore R, Rustomjee R, Milovic A, Jones M, O'Brien SM, Persing DH, Ruesch-Gerdes S, Gotuzzo E, Rodrigues C, Alland D, Perkins MD, , 2010. Rapid molecular detection of tuberculosis and rifampin resistance. N Engl J Med 363: 10051015.[Crossref]
  21. Caviedes L, Lee TS, Gilman RH, Sheen P, Spellman E, Lee EH, Berg DE, Montenegro-James S, , 2000. Rapid efficient detection and drug susceptibility testing of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures. The Tuberculosis Working Group in Peru. J Clin Microbiol 38: 12031208.
  22. Caviedes L, Moore DA, , 2007. Introducing MODS: a low-cost, low-tech tool for high-performance detection of tuberculosis and multidrug resistant tuberculosis. Indian J Med Microbiol 25: 8788.[Crossref]
  23. Moore DA, Mendoza D, Gilman RH, Evans CA, Hollm Delgado MG, Guerra J, Caviedes L, Vargas D, Ticona E, Ortiz J, Soto G, Serpa J; Tuberculosis Working Group in Peru, 2004. Microscopic observation drug susceptibility assay, a rapid, reliable diagnostic test for multidrug-resistant tuberculosis suitable for use in resource-poor settings. J Clin Microbiol 42: 44324437.[Crossref]
  24. Moore DA, Evans CA, Gilman RH, Caviedes L, Coronel J, Vivar A, Sanchez E, Piñedo Y, Saravia JC, Salazar C, Oberhelman R, Hollm-Delgado MG, LaChira D, Escombe AR, Friedland JS, , 2006. Microscopic-observation drug-susceptibility assay for the diagnosis of TB. N Engl J Med 355: 15391550.[Crossref]
  25. Shiferaw G, Woldeamanuel Y, Gebeyehu M, Girmachew F, Demessie D, Lemma E, , 2007. Evaluation of microscopic observation drug susceptibility assay for detection of multidrug-resistant Mycobacterium tuberculosis . J Clin Microbiol 45: 10931097.[Crossref]
  26. Ejigu GS, Woldeamanuel Y, Shah NS, Gebyehu M, Selassie A, Lemma E, , 2008. Microscopic-observation drug susceptibility assay provides rapid and reliable identification of MDR-TB. Int J Tuberc Lung Dis 12: 332337.
  27. Minion J, Leung E, Menzies D, Pai M, , 2010. Microscopic-observation drug susceptibility and thin layer agar assays for the detection of drug resistant tuberculosis: a systematic review and meta-analysis. Lancet Infect Dis 10: 688698.[Crossref]
  28. World Health Organization, 2009. Strategic and Technical Advisory Group for Tuberculosis (STAG-B): Report of the Ninth Meeting. 9–11 November 2009. Available at: http://www.who.int/tb/advisorybodies/stagbreport2009.pdf. Accessed August 6, 2011.
  29. Coughlin SS, Trock B, Criqui MH, Pickle LW, Browner D, Tefft MC, , 1992. The logistic modeling of sensitivity, specificity, and predictive value of a diagnostic test. J Clin Epidemiol 45: 17.[Crossref]
  30. Mendoza A, Castillo E, Gamarra N, Huamán T, Perea M, Monroi Y, Salazar R, Coronel J, Acurio M, Obregón G, Roper M, Bonilla C, Asencios L, Moore DA, , 2011. Reliability of the MODS assay decentralization process in three health regions in Peru. Int J Tuberc Lung Dis 15: 217222.
  31. Coronel J, Roper M, Mitchell S, Castillo E, Gamarra N, Drobniewski F, Luna G, Mendoza A, Moore DA, , 2011. MODS accreditation process for regional reference laboratories in Peru: validation by GenoType MTBDRplus. Int J Tuberc Lung Dis 14: 14751480.

Data & Media loading...

  • Received : 08 Aug 2011
  • Accepted : 21 Nov 2011

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error