Supplementary file 1_Establish a visual loop-mediated isothermal amplification (LAMP) method for rapid detection avian colibacillosis.pdf

Objective<p>To develop a rapid visual loop-mediated isothermal amplification (LAMP) assay for the detection of pathogenic Escherichia coli in poultry-associated samples.</p>Methods<p>A total of 650 samples were collected from 11 large-scale poultry farms in Jilin Province, China, from which 632 bacterial isolates were recovered. Four sets of LAMP primers were designed based on conserved genomic regions identified by sequence alignment.

Reaction temperature, incubation time, and Bst DNA polymerase dosage were optimized. The limit of detection, visual colorimetric performance, and cross-reactivity were evaluated, and the clinical diagnostic performance was compared with conventional PCR.</p>Results<p>The optimized LAMP assay produced detectable amplification within 45 min at 63 °C, with a limit of detection of 3.6 CFU/mL. Positive reactions turned yellow-green, whereas negative reactions remained orange, enabling naked-eye discrimination.