Fluorescence imaging method can detect tuberculosis infection in an hour

Aug. 27, 2018
The fluorescence imaging technique can diagnose live tuberculosis in an hour and help monitor the efficacy of treatments.

A team of researchers at the Stanford University School of Medicine (Stanford, CA) has developed a two-piece fluorescent probe that is activated when it comes in contact with tuberculosis (TB) bacteria in phlegm. The technique can diagnose live TB in an hour and help monitor the efficacy of treatments.

Jianghong Rao, Ph.D., a professor of radiology at the School of Medicine and the senior author of a paper describing the work, says that current methods for TB diagnosis can take up to two months to complete—a stretch during which infected individuals could spread the disease broadly, even if they don't know they are infected. A quicker diagnosis could curtail the infection rate. What's more, the new method is cheaper and easier to carry out, ideally enabling healthcare providers in poorer communities to one day adopt the technology.

To diagnose TB, clinicians need to collect a sample of sputum, cultivate it in the lab, and wait for the bacteria to grow to detectable level. It also requires specialized facilities, which are missing in many hospitals worldwide. The new imaging technique, however, uses conventional fluorescence microscopes that nearly all hospitals have and that require no special training, Rao says. All that is needed is a sample of the patient's sputum that can be prepared and put under the microscope for analysis.

Related: A breath screen for active tuberculosis at the point-of-care

The tactic harnesses a newly created two-piece fluorescent probe, which is combined with the sputum sample and gets activated when it comes in contact with TB bacteria. One part of the probe is responsible for detecting live TB, thus creating the telltale glow, while the second part—a molecule that binds specifically to the TB microbe—localizes the glow to the bacterium. The concentrated fluorescence allows scientists to not only see the rod-shaped bacteria themselves, but also to track their distribution in infected host cells.

"For cases of drug-susceptible TB, the treatment success rates are at least 85%, but the rate of success is only 54% for multidrug-resistant TB, which requires longer treatments and more expensive, more toxic drugs," Rao says.

Researchers applied the fluorescent probe to a sputum sample collected from a tuberculosis-positive patient; the bright green shows where there is live tuberculosis. (Image credit: Jianghong Rao)

The fluorescent probe, Rao says, can help determine the appropriate drug by showing which bacteria are still alive in the patient sample: those that are alive glow green, while those that aren't (or are a different species of bacteria) appear dark.

Outside the clinic, Rao says the technique could help scientists developing new TB drugs figure out which drugs work best for each particular strain. Now, he and his colleagues are planning to test the probe and to work on obtaining approval from the U.S. FDA.

Full details of the work appear in the journal Science Translational Medicine.

About the Author

BioOptics World Editors

We edited the content of this article, which was contributed by outside sources, to fit our style and substance requirements. (Editor’s Note: BioOptics World has folded as a brand and is now part of Laser Focus World, effective in 2022.)

Sponsored Recommendations

Request a quote: Micro 3D Printed Part or microArch micro-precision 3D printers

April 11, 2024
See the results for yourself! We'll print a benchmark part so that you can assess our quality. Just send us your file and we'll get to work.

Request a free Micro 3D Printed sample part

April 11, 2024
The best way to understand the part quality we can achieve is by seeing it first-hand. Request a free 3D printed high-precision sample part.

How to Tune Servo Systems: The Basics

April 10, 2024
Learn how to tune a servo system using frequency-based tools to meet system specifications by watching our webinar!

Precision Motion Control for Sample Manipulation in Ultra-High Resolution Tomography

April 10, 2024
Learn the critical items that designers and engineers must consider when attempting to achieve reliable ultra-high resolution tomography results here!

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!