Novel imaging to identify if TB drugs are working

Tuberculosis patients who are not cured of the infection can develop multi-drug resistant TB and have to take as many as six drugs for two years.

Now, researchers at University of Pittsburgh have found that sophisticated lung imaging can show well in time whether or not a treatment drug is able to clear tuberculosis (TB) lung infection in humans.

The findings indicate the animal model can correctly predict which experimental agents have the best chance for success in human trials.

"Our challenge is to find more effective treatments that work in a shorter time," said senior investigator JoAnne L Flynn, professor of microbiology and molecular genetics.

In previous research, Flynn's colleagues at the National Institutes of Health found that the drug linezolid effectively treated XDR-TB patients who had not improved with conventional treatment.

To further examine the effects of linezolid, Flynn and her collaborators performed PET/CT scans in TB-infected humans and macaques, which also get lesions known as granulomas in the lungs.

In a PET scan, a tiny amount of a radioactive probe is injected into the blood that gets picked up by metabolically active cells, leaving a "hot spot" on the image.

The researchers found that humans and macaques had "hot spots" of TB in the lungs that, in most cases, improved after drug treatment.

CT scans, which show anatomical detail of the lungs, also indicated post-treatment improvement.

One patient had a "hot spot" that got worse and further testing revealed his TB strain was resistant to linezolid.

"We plan to use this PET scanning strategy to determine why some lesions do not respond to certain drugs and to test candidate for anti-TB agents. This might give us a way of tailoring treatment to individuals," Flynn noted.

The findings were published online in the journal Science Translational Medicine.