Tuberculosis was traditionally regarded as a disease that mainly afflicted developing countries, since environmental factors like poor sanitary conditions, population overcrowding, nutritional deficiencies, and impaired immunity plays a significant role in the pathogenesis of the disease. However, due to the rising prevalence of immune disorders in western countries due to viral infections like HIV, tuberculosis is becoming a major problem in western countries as well.
The chronic respiratory illness is caused by invasion and multiplication of mycobacterium tuberculosis in the apical lungs, which can also be transmitted to others via droplet infection. Individuals with a history of compromised immune systems are at much higher risk of contracting the infection.
A research team at the Texas A&M Health Science Center College of Medicine, led by Dr. Jeffery Cirillo, has been working for past six years to improve the speed of the diagnostic process from a period of weeks to a few hours. This is extremely helpful to medial practitioners in several ways: early administration of treatment to TB patients helps in decreasing the duration of the illness, and also helps in the prevention of the spread of infection. It is estimated that 10% of all the infected individuals develop chronic illness from tuberculosis that is marked by substantial weight loss, persistent low-grade fever, night sweats, and coughing spells with copious amounts of blood-tinged sputum. If left untreated or undiagnosed (especially in developing countries), the survival rate for the disease is only 50%.
Cirillo and associates are very close to the discovery of a fast and reliable diagnostic method to identify TB in infected patients. The funding to support this research came from Wellcome Trust and the Bill and Melinda Gates Foundation.
“In a project this ambitious, one of the main challenges is maintaining enough funding to keep us moving forward,” said Cirillo. “Right now, we’re at maybe an 18-month window for this device to be out serving patients.”
Details of the research results:
Cirillo’s new TB research tool allows investigators to combine the sputum sample from potential patients with a reactive substance. The fluorescence activity is then studied by a hand-held, battery-operated device to give an on-the-spot diagnosis to patients.
Cirillo explained: “We’ve identified a fluorescence substrate that reacts with the bacteria. This gives us a very sensitive signal that wouldn’t be possible otherwise.”
Most conventional TB diagnostic procedures involve identification of bacterium in a special culture medium by observing the growth of colonies — a process that may take weeks or even months. However, this test is more specific, quick, and reliable. The basis of this test is to identify a special enzyme that is specific to mycobacterium activity. No other study or test has identified this enzyme before.
The research team is currently working on developing further techniques that would allow investigators to test bacterial activity in other biological samples, such as tissue or urine.
“We would like to apply it in all respiratory diseases,” explained Cirillo. “The first applications in the next few years will be TB.”
The Texas A&M spinout company GBDbio and Stanford University’s Dr. Jianghong Rao also contributed in this research. Additionally, many other institutions supported the research, including Doctors Without Borders, Clinton Health Access Initiative ,and the World Health Organization.
Cirillo is now working on obtaining additional funding to reproduce the same quality results in other labs. This is the final but most crucial step, and will be followed by manufacturing and distribution processes of test kits.
“We’ve done smaller scale testing in hundreds of samples,” Cirillo added. “To validate for worldwide use, it will require thousands of tests and validation in multiple labs outside our own.”
According to recent estimates, approximately 33.33% of the world’s population may have tuberculosis. Due to poor sanitation, chronic course of illness, and spread of infection via droplets (bacteria is transmitted by coughing and sneezing), it is expected that 1% of the world’s population develops active TB each year. There are several varieties of TB that affect multiple organs besides the lungs, such as the female genital tract, colon, and skin.