Accuracy of the Phenotypic 1G Test to Detect Mycobacterium tuberculosis and Drug Resistance From Sputa in the US-Mexico Border

Aguirre M.; Ayala D.; Garcia J.I.; Martinez-Lopez Y.E.; Hicks A.D.; Chacon N.; Gay-Cobb A.; Schami A.; Zavala-Perez S.; Dominguez-Trejo I.A.; Cruz-Gonzalez A.M.; Loera-Salazar R.; Rodríguez-Herrera J.E.; Garcia-Oropesa E.M.; Lee M.; Rendón A.; Wang S.-H.; Yotebieng M.; Evans C.A.; Torrelles J.B.; Restrepo B.I. · Journal of Infectious Diseases (2026) · DOI: 10.1093/infdis/jiaf638

Resumen

Background: With >10 million new tuberculosis (TB) cases per year, a limitation to TB control is the lack of simple and accurate tests for diagnosis and drug susceptibility testing (DST) in endemic regions. We evaluated the accuracy of the first-generation, low-complexity phenotypic TB test (1G test), designed for simultaneous Mycobacterium tuberculosis (Mtb) detection and resistance to isoniazid, rifampicin, and moxifloxacin, suitable for resource-limited settings. Methods: A cross-sectional study was conducted with sputa from 426 possible pulmonary TB cases from 2 small Mexican cities bordering Texas. The 1G test was compared against phenotypic TB detection tests in the region, specifically acid-fast bacilli smear microscopy and Mycobacteria Growth Indicator Tube (MGIT) culture, as well as MGIT-DST for resistance to isoniazid, rifampicin, and moxifloxacin. Results: The 1G test demonstrated ≥98% sensitivity for Mtb detection; 100% sensitivity and 91% (rifampicin), 94% (isoniazid), and 97% (moxifloxacin) specificity for DST; and less contamination than the MGIT (3.5% vs 8.1%, P < .05). The 1G test time to detection of Mtb and simultaneous DST was 17 days, while the MGIT-DST required 2 steps: 7 days for Mtb detection plus 14 more days for DST (21 days total). Our study site drug-resistant TB prevalence was 14% when testing all consecutively enrolled participants vs 6% by passive reporting. Conclusions: The 1G test is a low-complexity phenotypic TB diagnostic method that is a practical replacement to current culture-based tests. Future studies are warranted to evaluate implementation of the 1G test in decentralized clinics that lack molecular tools, resources, and expertise. © The Author(s) 2025. Published by Oxford University Press on behalf of Infectious Diseases Society of America.

Instituciones: Universidad Peruana Cayetano Heredia