Detection of Campylobacter jejuni Based on a Real-Time Fluorescence Loop-Mediated Isothermal Amplification Method

Abstract

Campylobacter jejuni (C. jejuni), a foodborne pathogenic bacterium, is among the most prevalent causes of human gastroenteritis globally. We developed and evaluated a loop-mediated isothermal amplification (LAMP) method to detect C. jejuni. Outer primers and inner primers were designed based on the hipO gene. The ratio between the concentrations of the inner and outer primers and the reaction temperature were then optimized to achieve optimal assay conditions. The analytical specificity tests showed that, among 12 genera of 74 pure bacterial culture strains, only four C. jejuni isolates could be detected, whereas no amplification was observed in C. coli, C. lari, and the other 11 genera of foodborne pathogens ( $n=70$ ). Moreover, the LAMP assay showed a higher analytical sensitivity (34.2 fg μL-1) than the conventional PCR method (342 fg μL-1). The limit of detection of C. jejuni based on the LAMP assay was 103 CFU g-1 in the artificially spiked samples of chicken meat. In conclusion, the developed LAMP assay will be a powerful and practical tool for the fast, specific, and sensitive detection of C. jejuni.