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bioRxiv · 10.64898/2026.07.24.740582

A Portable Fluorescence Platform for Decentralized One-Health mcr-1 Monitoring

Vargas-Reyes, M.·Alcantara, R.·Herrera, C.·Townsend, M.·Flores-Jimenes, K.·Raymundo, C.·Milon, P.
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Abstract

Antimicrobial resistance (AMR) represents a major global health threat, with plasmid-borne mcr genes driving colistin resistance and exposing critical gaps in One-Health surveillance across human, animal, and environmental reservoirs. The most prevalent variant, mcr-1, remains difficult to monitor in resource-limited settings due to the lack of rapid, affordable, and field-deployable molecular tools. Here, we developed C12amcr, an integrated molecular toolbox that combines pre-amplification PCR with a fluorescent CRISPR-Cas12a assay targeting a conserved region of mcr-1 and a custom low-cost, hand-held 3D-printed portable fluorometer. Under optimized conditions, the assay achieved a limit of detection of 630 cells/mL. In poultry feces spiked with mcr-1-positive E. coli, C12amcr detected as few as 1,800 cells/mL. When tested on 22 community-derived E. coli isolates, the assay showed 100% concordance with both next-generation sequencing for mcr-1 detection and phenotypic colistin susceptibility testing by broth microdilution. The accompanying portable fluorometer performed equivalently to a laboratory microplate reader while enabling fully decentralized workflows compatible with portable PCR platforms. By integrating locally produced molecular reagents, straightforward protocols, and an accessible field-ready fluorescence reader, C12amcr overcomes key barriers to decentralized AMR surveillance and provides a practical, scalable solution for One-Health monitoring in resource-limited settings.

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Vargas-Reyes, M., Alcantara, R., Herrera, C., Townsend, M., Flores-Jimenes, K., Raymundo, C., Milon, P.. 2026-07-27. A Portable Fluorescence Platform for Decentralized One-Health mcr-1 Monitoring. https://doi.org/10.64898/2026.07.24.740582

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