CRISPR Tools Reveal Hidden Genes Behind Tuberculosis Drug Resistance

Drug-resistant tuberculosis remains one of the most stubborn obstacles in global infectious disease control, and a new mini review in Molecular Biology Reports argues that the CRISPR-Cas system has become the decisive research tool for understanding how Mycobacterium tuberculosis evades antibiotics. The review, led by Yanhui Yuan and colleagues at Hunan Normal University and partner institutions in Changsha, China, synthesizes recent progress in applying CRISPR and CRISPR-associated (Cas) technologies to dissect drug resistance mechanisms in M. tuberculosis, and proposes the CRISPR-Cas system as an integrated platform capable of transforming research paradigms in the field. Published on 17 October 2026 as volume 53, article number 1759 of the journal, the work arrives at a moment when the World Health Organization’s 2024 global tuberculosis report and successive clinical reviews describe drug-resistant TB as a persistent and escalating threat to public health.

The scale of the problem gives the review its urgency. Tuberculosis still kills more people than any other single bacterial infection, and the emergence of multidrug-resistant and extensively drug-resistant strains has narrowed treatment options dramatically. Recent assessments published in Nature Reviews Microbiology in 2024 characterize drug-resistant tuberculosis as a persistent global health concern, while clinical reviews from 2025 and 2026 outline advances and prospects for treatment strategies involving antimicrobial peptides, nanotechnology, and computational design. Against this backdrop, the authors contend that addressing drug resistance requires a comprehensive molecular understanding of resistance mechanisms in M. tuberculosis, and that the CRISPR-Cas system, originally recognized as a bacterial adaptive immune architecture, has matured into an efficient genome-editing toolkit for a wide range of organisms and has opened new research directions specifically for tuberculosis drug resistance.

Technically, the CRISPR-Cas system operates through an RNA-guided nuclease that can be programmed to target almost any genomic sequence. The evolutionary classification of these systems, first systematized by Makarova and colleagues in Nature Reviews Microbiology in 2011 and updated in 2020 with a burst of class 2 and derived variants, distinguishes class 1 multi-subunit effectors from class 2 single-protein effectors such as Cas9 and Cas12a. The programmability that made Cas9 famous, described by Doudna and Charpentier as the new frontier of genome engineering with CRISPR-Cas9 in Science in 2014, rests on a simple design principle: a single guide RNA directs the Cas protein to a matching DNA target adjacent to a short protospacer-adjacent motif. This principle underlies every application the review surveys, from targeted gene disruption to transcriptional repression, base editing, and genome-wide screening.

Applying these tools to M. tuberculosis posed distinctive challenges that the review documents in detail. The mycobacterial genome is notoriously resistant to homologous recombination, and double-strand breaks introduced by Cas9 tend to be lethal rather than repairable in this organism. Early genome-editing work in mycobacteria therefore exploited the organism’s own low-fidelity nonhomologous end-joining repair system, driven by Ku, ligase D, and ligase C, as described by Gong and colleagues in Nature Structural and Molecular Biology in 2005. Building on that insight, Yan and colleagues reported in mBio in 2020 a CRISPR-assisted nonhomologous end-joining strategy for efficient genome editing in M. tuberculosis, sidestepping the need for homologous recombination altogether. The review also notes that a pangenome-wide association study published in Microbiology Spectrum in 2024 revealed the selective absence of CRISPR genes Rv2816c-19c in drug-resistant M. tuberculosis, an intriguing hint that endogenous CRISPR-related loci may themselves correlate with resistance phenotypes.

Because direct Cas9 cleavage is so often lethal in mycobacteria, the most productive applications have been catalytically dead variants that repress rather than cut. CRISPR interference, or CRISPRi, uses a nuclease-dead Cas9 fused to transcriptional repression domains, guided by a single guide RNA to bind promoter or coding regions and sterically block RNA polymerase. Choudhary and colleagues demonstrated gene silencing by CRISPR interference in mycobacteria in Nature Communications in 2015, and Rock and colleagues established a programmable transcriptional repression platform in mycobacteria using an orthogonal CRISPR interference system in Nature Microbiology in 2017. The review emphasizes that CRISPRi avoids the double-strand break problem entirely, allowing researchers to titrate gene expression downward without killing the cell, which is essential when the genes under study are required for growth. Libraries of systematically attenuated CRISPR guide RNAs, described by Jost and colleagues in Nature Biotechnology in 2020, extend this titration logic to quantitative expression control.

Genome-wide CRISPRi screening has since become the review’s centerpiece application for resistance research. Li and colleagues reported in Nature Microbiology in 2022 that CRISPRi chemical genetics and comparative genomics identify genes mediating drug potency in M. tuberculosis, combining pooled repression libraries with drug challenge to reveal determinants of antibiotic sensitivity. Wang and colleagues applied whole-genome CRISPRi screening to an isoniazid-resistant strain in Nature Communications in 2024, identifying druggable vulnerabilities, and a 2026 Nature Communications study by the same group extended the approach to genetically diverse drug-resistant strains, revealing both shared and strain-specific vulnerabilities. Yan and colleagues contributed combined CRISPR screening for genetic and chemical-genetic interaction profiling in Science Advances in 2022, and in Advanced Science in 2024 used CRISPR screening with comparative liquid chromatography-mass spectrometry to identify genes mediating the efficacy of delamanid and pretomanid, two critical drugs for resistant TB. A 2026 mBio study by Theriault and colleagues added an ex vivo challenge model revealing temporally dependent gene essentiality in intracellular M. tuberculosis, showing that essentiality shifts over the course of infection.

The screening approach has also resolved specific resistance puzzles. Poulton and colleagues showed in Antimicrob Agents Chemother in 2022 that mutations in rv0678 confer low-level resistance to benzothiazinone DprE1 inhibitors, a finding that clarified how a transcriptional regulator shapes susceptibility to a novel drug class. Carlos Alonso and colleagues reported in Tuberculosis in 2025 that CRISPRi-mediated repression of efflux pumps reveals Rv1258c as a key contributor to pyrazinamide resistance, directly implicating a specific transporter in a first-line drug phenotype. Roberts and colleagues demonstrated in the same journal in 2024 that EfpA is required for regrowth of M. tuberculosis following isoniazid exposure, suggesting that efflux machinery governs post-exposure recovery rather than acute killing. Silveiro and colleagues used CRISPRi in Frontiers in Cellular and Infection Microbiology in 2023 to characterize mycobacterial peptidoglycan modifications that promote beta-lactam resistance and intracellular survival, linking cell-wall remodeling to both drug phenotype and host adaptation. Multiplexed transcriptional repression, reported by McNeil and colleagues in iScience in 2022, identified a network of bactericidal interactions between mycobacterial respiratory complexes, and a Cas12a-based CRISPR interference system for multigene regulation, described by Fleck and Grundner in the Journal of Biological Chemistry in 2021, enabled simultaneous repression of multiple genes.

Beyond repression, the review surveys programmable base editing as a route to introducing precise resistance mutations without double-strand breaks. Base editors, pioneered by Komor and colleagues in Nature in 2016 with programmable editing of a target base without cleavage, and extended by Gaudelli and colleagues in 2017 to A-to-G editing, fuse a Cas nickase to a deaminase enzyme that chemically converts individual nucleotides. Zhao and colleagues showed in Nucleic Acids Research in 2022 that imperfect guide RNAs enable CRISPR single-base editing with both adenine and cytosine base editors. In mycobacteria specifically, Ding and colleagues reported in Frontiers in Genome Ed in 2021 programmable base editing in M. tuberculosis using an engineered CRISPR RNA-guided cytidine deaminase, and Zhang and colleagues developed PAM-expanded Streptococcus thermophilus Cas9 C-to-T and C-to-G base editors for mycobacteria in Engineering in 2022. These systems allow researchers to recreate resistance-associated point mutations in controlled laboratory strains, establishing causality that association studies alone cannot deliver.

The review also connects CRISPR-Cas technology to diagnostics and computational integration. Aptamer-based CRISPR-Cas powered diagnostics, described by Kadam and colleagues in Applied Biological Chemistry in 2023, can detect diverse biomarkers and small molecule targets, and the broader application of the CRISPR-Cas system in antibiotic resistance, surveyed by Tao and colleagues in Infection and Drug Resistance in 2022 and updated by Zhang and colleagues in Microbiology Research in 2025, spans detection, mechanistic dissection, and therapeutic development. Machine learning approaches, including accurate and rapid prediction of tuberculosis drug resistance from genome sequence data using traditional algorithms and convolutional neural networks reported by Kuang and colleagues in Scientific Reports in 2022, and rare-variant leveraging with statistical learning models described by Chen and colleagues in EBioMedicine in 2019, complement CRISPR-derived functional data. The review notes that artificial intelligence-assisted design, mining, and modification of CRISPR-Cas systems, surveyed by Mao and colleagues in 2025, is accelerating guide RNA design and effector engineering, and that whole-genome screening approaches continue to develop rapidly.

The authors conclude that the CRISPR-Cas system should be viewed as an integrated platform rather than a collection of separate techniques, one that unifies gene editing, transcriptional control, screening, base editing, diagnostics, and computational modeling into a coherent framework for resistance research. They argue that this integration can transform research paradigms and enhance understanding of M. tuberculosis drug resistance mechanisms at a level of molecular precision that earlier association-based approaches could not reach. The work was supported by the National Natural Science Foundation of China, the Science and Technology Program of Hunan Province, the Department of Education of Hunan Province, and a joint research grant from the Hunan Chest Hospital and Hunan Normal University. The authors declare no competing interests. As drug-resistant tuberculosis continues to outpace conventional drug development, the review positions CRISPR-Cas technology as the field’s most versatile instrument for identifying the vulnerabilities that new therapies must exploit.

Subject of Research: Utilization of the CRISPR-Cas system for investigating tuberculosis drug resistance

Article Title: Utilization of the CRISPR-Cas system for investigating tuberculosis drug resistance

Article References: Yuan, Y., Deng, J., Li, X., Zheng, X., Tan, Y., & Xu, K. (2026). Utilization of the CRISPR-Cas system for investigating tuberculosis drug resistance. Molecular Biology Reports, 53(1), Article 1759. https://doi.org/10.1007/s11033-026-12954-w

Image Credits: AI Generated

DOI: 10.1007/s11033-026-12954-w

Keywords: Utilization, CRISPR-Cas, system, investigating, tuberculosis, drug, resistance, scientific research