Revolutionizing Tuberculosis Detection with a CRISPR Mouth-Swab Test
In a groundbreaking development, researchers at Tulane University have developed a new CRISPR-based test called ActCRISPR-TB. This innovative test can detect tuberculosis (TB) from a simple tongue swab, making it more accessible in low-resource settings where sputum collection may be challenging.
ActCRISPR-TB builds on the team's earlier two-step CRISPR assay for detecting Mycobacterium tuberculosis cell-free DNA in blood. The test integrates isothermal amplification and CRISPR-Cas12a detection in a single 'one-pot' reaction, providing rapid and accurate results.
In a study, ActCRISPR-TB identified TB in 74% of tongue swab samples, outperforming traditional testing methods. However, it's important to note that tongue swabs still face challenges, as 26% of tuberculosis cases that were positive by sputum testing produced negative tongue-swab results in the trial. The authors caution that lessons from COVID-19 testing, such as repeat testing or using more homogeneous saliva samples, may help address these challenges.
The need for sputum and expensive equipment is eliminated by ActCRISPR-TB, which could offer a path to earlier detection and treatment of tuberculosis, a disease that affects more than 10 million people each year. About 40% of TB cases go undiagnosed due to reliance on sputum-based testing.
The team plans to integrate AI into the system to help screen for more efficient diagnostic systems for various pathogens, including COVID-19 and monkeypox. Huang and colleagues envision expanding the ActCRISPR-TB platform beyond tuberculosis for potential use in diagnosing other pathogens.
ActCRISPR-TB has been validated in more than 600 clinical specimens across multiple sample types. In under an hour, ActCRISPR-TB can flag infection with a paper strip readout similar to a home COVID-19 test. This rapid, affordable, and accessible test could be a game-changer in the global fight against tuberculosis, a critical step toward the goal of ending TB.
However, larger community-based studies are needed to confirm the performance of ActCRISPR-TB in real-world screening, particularly among asymptomatic individuals with low bacterial loads. Variability in M. tuberculosis DNA levels on the tongue can complicate the translation of swab-based diagnostics into clinical practice, but lessons from COVID-19 testing may help address these challenges.
ActCRISPR-TB has the potential to diagnose TB in patients who cannot provide sputum, particularly in low-resource settings, revolutionizing the way TB is detected and treated.
