CRISPR4TB - CRISPR-Cas-Based Point-of-Care Diagnostic Testing for Tuberculosis

Tuberculosis (TB) kills an estimated 1.25 million people each year, making it the single deadliest infectious disease. Unfortunately, TB disproportionately impacts low- and middle-income countries (LMICs); 98% of the global TB cases occur within LMICs, leading to devastating effects. Furthermore, the proliferation of this disease has resulted in widespread misuse of antibiotics, leading to the development of substantial drug resistance. Indeed, in the worst affected regions, drug resistance among recurring TB infections has risen above 50%.

Most TB deaths are preventable if diagnosed early. However, almost a quarter of all TB cases go undiagnosed. Similarly, the proliferation of drug resistances in TB can be partially attributed to a scarcity of effective methods for identifying resistance markers, which results in poor antibiotic stewardship. Unfortunately, contemporary diagnostic technologies have proved insufficient for diagnosing TB and associated drug resistances, particularly at the point-of-care (PoC). Few technologies exist that can quickly and accurately diagnose TB and simultaneously determine resistances, and the ones that do are large and expensive, precluding their use in LMICs. They are also overly reliant on sputum samples, which can be difficult to obtain, particularly in low-resource settings.

This project aims to develop an affordable, portable, and rapid diagnostic platform technology that can multiplex 14 targets for TB and associated markers for drug resistance from a single sample. This technology will be paper-based and leverage electrochemical signalling to facilitate miniaturisation and provide quantitative readouts of disease.

These paper-based tests will be constructed using a recently patented technology from ETHZ: laser-induced graphenization of cellulose. This manufacturing process is affordable, scalable, and rapid, making it ideal for constructing PoC devices. This technology will be combined with novel CRISPR–Cas-based biosensing assays, specifically engineered to facilitate the detection of single-nucleotide polymorphisms (SNPs) associated with drug resistance. Crucially, this combination of paper-based graphenized electrodes and CRISPR–Cas will enable detection of TB in blood, rather than sputum, dramatically increasing accessibility. To facilitate deployment at the PoC, these technologies will be integrated into a highly affordable cartridge & reader system in collaboration with CSEM.

Swiss TPH contributes to the evaluation and validation of the diagnostic platform. In collaboration with ETH Zurich, Swiss TPH tests the new CRISPR–Cas assay using biobanked biological samples. In addition, Swiss TPH conducts a clinical proof-of-concept study in Georgia, together with the National Center for Tuberculosis and Lung Disease, to estimate the diagnostic accuracy of the assay in patient samples.

This device will fill a critical gap in the current treatment pathway of TB and bring care to millions of underserved patients, particularly in LMICs. By enabling rapid diagnosis of the disease, this technology will facilitate more accurate and timely medical interventions, ultimately improving patient outcomes and decreasing the burdens on healthcare systems. Moreover, by focusing on common AMR markers, this technology will improve antimicrobial stewardship and be a valuable weapon in the fight against AMR.