Scientists have finally developed a noninvasive tuberculosis test for a pool of people for whom such assessments have previously been difficult: people who don't have HIV. The researchers' test detects active tuberculosis infections from urine samples. They say the technology has urgently needed and broad implications for screening, transmission control, and treatment management.
Seeking to capture small amounts of a sugar called LAM (which partially comprises the tuberculosis bacterium's outer coat) in urine, researchers screened 37 compounds to narrow in on a copper complex dye called RB221 that they embedded in tiny hydrogel meshes to form structures called nanocages.
The RB221 nanocages trapped LAM from urine, increasing detection sensitivity by 100- to 1,000 fold, all while excluding interfering compounds from the samples that could confound results.
In 48 Peruvian HIV-negative tuberculosis patients who hadn't yet been treated, the new test detected infections with greater than 95% sensitivity. What's more, elevated LAM concentrations in urine correlated with increased amounts of bacteria and more severe disease (as measured by weight loss or cough).
The researchers also created nanocages to trap and detect other hallmarks of infection including very low abundance molecules named ESAT6 and CFP10. According to the authors, their next steps are to compare urinary LAM in patients before and after therapy to evaluate potential treatment-induced changes.
A urine test for accurate tuberculosis detection
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