New Test for TB Can Detect Antibiotic Resistant Strains Interview with:

Susan E. Dorman, M.D Associate Professor of Medicine, Division of Infectious Diseases Johns Hopkins University School of Medicine, Baltimore

Dr. Dorman

Susan E. Dorman, M.D
Associate Professor of Medicine, Division of Infectious Diseases
Johns Hopkins University School of Medicine, Baltimore What is the background for this study? What are the main findings?

Response: Tuberculosis, also called “TB” is one of the top 10 causes of death worldwide, according to the World Health Organization.  TB is caused by bacteria called Mycobacterium tuberculosis.  In 2015, over 10 million people became sick from TB and 1.8 million people died from TB.  This is a lot of people – diagnosing and treating TB to improve their health is important.  Because TB usually involves the lungs, it can be passed from person to person through the air, and thus, diagnosing and treating TB is critical to  reduce the spread of TB.   Drug-resistant TB — TB caused by bacteria that are resistant to commonly used TB antibiotics — is a serious problem.  In 2015 an estimated 480,000 people had multidrug-resistant TB.

We have been working to develop better, faster ways to diagnose TB and drug-resistant TB.  A new test was developed as a partnership between Rutgers University and Cepheid (Sunnyvale, CA), and development was supported by the US National Institutes of Health (NIH).  The new test was designed to detect Mycobacterium tuberculosis bacteria in sputum, and to simultaneously detect whether the bacteria are resistant to several of the main antibiotics (isoniazid, fluoroquinolones, and aminoglycosides) used to treat TB.  The test takes about two hours from sample to result.

The NEJM article describes the results of a study that was undertaken in China and South Korea to understand how well the new test works, compared against gold standard tests. What should clinicians and patients take away from your report?

Response: The main finding is that the new test accurately detected mutations associated with resistance to isoniazid, fluoroquinolone, and aminoglycoside resistance. What recommendations do you have for future research as a result of this study?

Response: The most exciting message is that introduction of this test will speed up the detection of drug resistant TB.  This is important for several reasons — getting TB patients on the best possible, potentially life-saving treatment; implementing infection control procedures that prevent the further spread of drug resistant TB; and improving the triage of TB patients to or away from “shorter course” MDR-TB treatment.  A main use of this test will be in guiding selection of the optimal medication regimen to treat TB patients who have rifampin-resistant TB based on initial TB testing. The new test may also be useful in all TB patients (including those whose initial testing shows TB that is not resistant to rifampin), since the new test provides information about isoniazid, a key antibiotic in treating TB. Is there anything else you would like to add?

Response: Currently a few minor modifications are being made to the test in order to improve detection of isoniazid resistance — this work is being supported by the NIH and the Foundation for Innovative New Diagnostics.  We anticipate that licensing studies for CE-IVD will be completed in about 18 months and that the test will be available soon thereafter in the non-US market.  There is, and will continue to be, a need for work to determine exactly how to best place this new test in TB diagnostic testing algorithms so that the test can have the highest possible impact on patients’ health.  We envision that use of this new diagnostic test should go hand-in-hand with programs to ensure capacity (availability of medicines and trained clinicians) to safely and effectively treat patients with drug resistant TB.

Disclosures: This work was supported by the NIH.  Cepheid supplied the new test cartridges and instruments, but Cepheid had no role in the study design, implementation, analysis of results, or reporting of results. Thank you for your contribution to the community.


Evaluation of a Rapid Molecular Drug-Susceptibility Test for Tuberculosis 

Yingda L. Xie, M.D., Soumitesh Chakravorty, Ph.D., Derek T. Armstrong, M.H.S., Sandra L. Hall, M.P.H., Laura E. Via, Ph.D., Taeksun Song, Ph.D., Xing Yuan, M.D., Xiaoying Mo, Ph.D., Hong Zhu, M.D., Peng Xu, Ph.D., Qian Gao, Ph.D., Myungsun Lee, M.D., Jongseok Lee, Ph.D., Laura E. Smith, M.S., Ray Y. Chen, M.D., Joon Sung Joh, M.D., YoungSoo Cho, M.D., Xin Liu, M.D., Xianglin Ruan, M.D., Lili Liang, M.D., Nila Dharan, M.D., Sang-Nae Cho, D.V.M., Ph.D., Clifton E. Barry, III, Ph.D., Jerrold J. Ellner, M.D., Susan E. Dorman, M.D., and David Alland, M.D.

N Engl J Med 2017; 377:1043-1054September 14, 2017DOI: 10.1056/NEJMoa1614915

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions. 

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Last Updated on September 14, 2017 by Marie Benz MD FAAD