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MSU researcher plays role in reducing TB deaths by 95 percent by 2035

 

Photo of Dr. Alocilja

More people die from tuberculosis (TB) every year than from any other disease. About 1.7 million people die and another two billion people are infected with the disease annually.  Many places around the world, however, still lack access to affordable, community-based diagnostic testing, and the tests that are currently available are either not sensitive enough to detect the disease or too expensive.

An ambitious initiative, the “End TB Strategy,” is striving to reduce the incidence of TB by 90 percent and TB deaths by 95 percent by 2035. The only way this goal can be achieved is by developing new tools for fighting the deadly disease, such as improved point-of-care (POC) diagnostic tests that can be delivered to communities and first point-of-contact locations in the healthcare system. Samples must be easy to collect, and there needs to be a quick turnaround with results so that patients can be treated in a single visit, thereby avoiding patient follow-up.

Efforts focused on preventing TB and caring for its victims have been stalled by the unavailability of rapid, reliable, and universally accessible diagnosis methods. The primary testing method that many countries have relied on for detecting pulmonary TB is direct (unconcentrated) sputum smear microscopy (SSM). It is fast, simple, and inexpensive, but its sensitivity is only about 50 percent.  Another method rolled out by the World Health Organization (WHO) in 2010, called the Xpert MTB/RIF, is much more accurate, but also more expensive. The machine costs up to $40,000, and the cartridges cost $20 to $40 per test, depending on the country.

Dr. Evangelyn Alocilja, Michigan State University Department of Biosystems and Agricultural Engineering, in collaboration with fellow researchers Dr. Nirajan Bhusal, Dhulikhel Hospital at Kathmandu University, Nepal, Dr. Kenny Briceno, Universidad Cesar Vallejo and Hospital de Alta Complejidad La Libertad, Peru, and Dr. Hector Sanchez, Dr. Anaximandro Gomez, and Ms. Cristina Gordillo, El Colegio de la Frontera Sur and Mycobacteriology Laboratory, Mexico, developed a nanoparticle-based colorimetric biosensing assay (NCBA) that would be able to quickly and inexpensively detect acid-fast bacilli (AFB) in sputum samples. The methodology combined the principles of TB biology, nanotechnology, glycochemistry, and engineering, and applied the performance criteria identified years earlier by Dr. Prabha Desikan that a TB test that is 85 percent sensitive and 97 percent specific could save 400,000 lives annually. Researchers compared the NCBA technique against SSM and the Xpert MTB/RIF in 500 samples from patients suspected to have TB in Nepal and against the culture method in 1,200 sputum samples in Peru. Researchers also quantitatively evaluated NCBA against SSM. The NCBA test had matching sensitivity with both the Xpert MTB/RIF (with 85% sensitivity and 98% specificity compared to culture) for all 500 samples in Nepal and the 1,200 culture method samples in Peru. NCBA showed 47% increase in AFB count compared to SSM in Mexico. SSM only had a 40 percent sensitivity for the same samples.

"The NCBA technique will help facilitate quick treatment in a single clinical encounter and
contribute to meeting the goals of the 'End TB Strategy' by 2035."

The NCBA technique can be completed in 10 to 20 minutes through a simple four-step process, and costs an estimated $0.05 to $0.20 per test using a simple bright field microscope. Implementing NCBA in rural communities could help diagnose  TB cases faster, more accurately, and much more cost effectively. The NCBA technique used at the first point-of-contact by patients in clinics and other health care settings will help facilitate quick treatment in a single clinical encounter and contribute to meeting the goals of the “End TB Strategy” by 2035.

Contact Dr. Vangie Alocilja for more information.