Scientific Publications by FDA Staff

J Microbiol Methods 2020 Jul 21 [Epub ahead of print]

A loop-mediated isothermal amplification (LAMP) assay for the consensus detection of human pathogenic Campylobacter species.

Babu US, Harrison LM, Mammel MK, Bigley EC 3rd, Hiett KL, Balan KV

Most rapid identification methods for Campylobacter are designed to detect thermotolerant Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli). A growing number of thermosensitive Campylobacter species are now gaining recognition as emerging human pathogens. Methods are lacking for the rapid screening of these emerging species. Loop-mediated Isothermal Amplification (LAMP) is a nucleic acid amplification method that allows for the rapid and cost-effective detection of bacteria. Degenerate primers against the 16S rRNA sequences for C. jejuni, C. coli, C. lari, C. upsaliensis, C. ureolyticus, C. fetus, C. gracilis, C. rectus, and C. concisus were designed. Isothermal amplification was conducted using ATCC reference strains at 68¿°C for 30¿min using WarmStart® Colorimetric LAMP reagents. Positive reactions were indicated by a color change from pink to yellow; specificity to Campylobacter was confirmed using a restriction enzyme digest (RsaI). The developed LAMP reaction was specific for the reference strains, which was confirmed against an exclusivity panel that consisted of other enteric pathogens, including E. coli, Salmonella, Shigella, Helicobacter, and Arcobacter. This method was also validated for the detection of C. jejuni, C. coli, and C. lari in primary enrichment media from artificially contaminated fresh spinach samples. The LAMP method provides an option to rapidly screen for the presence of pathogenic Campylobacter spp. in field surveillance and trace-back analysis.