Rapid and Sensitive Detection of in Chickens Using Loop-Mediated Isothermal Amplification Combined with a Lateral Flow Dipstick.

Salmonellosis is a highly contagious bacterial disease that threatens both human and poultry health. Tests that can detect in the field are urgently required to facilitate disease control and for epidemiological investigations. Here, we combined loop-mediated isothermal amplification (LAMP) with a chromatographic lateral flow dipstick (LFD) to rapidly and accurately detect . LAMP primers were designed to target the gene. LAMP conditions were optimized by adjusting the ratio of inner to outer primers, MgSO concentration, dNTP mix concentration, amplification temperature, and amplification time. We evaluated the specificity of our novel LAMP-LFD method using six species and six related non- strains. All six of the strains, but none of the non- strains, were amplified. LAMP-LFD was sensitive enough to detect concentrations of subsp. serovar Pullorum genomic DNA as low as 89 fg/µl, which is 1,000 times more sensitive than conventional PCR. When artificially contaminated feed samples were analyzed, LAMP-LFD was also more sensitive than PCR. Finally, LAMP-LFD gave no false positives across 350 chicken anal swabs. Therefore, our novel LAMP-LFD assay was highly sensitive, specific, convenient, and fast, making it a valuable tool for the early diagnosis and monitoring of infection in chickens.