An immunomagnetic separation/loop-mediated isothermal amplification method for rapid direct detection of thermotolerant Campylobacter spp. during poultry production

Abstract

Aims: To develop a rapid test for thermotolerant Campylobacter in poultry faeces.

Methods and results: The reported method is based on immunomagnetic separation and loop-mediated isothermal DNA amplification (IMS/LAMP). This LAMP assay is specific (demonstrated using 10 Campylobacter strains and 13 non-Campylobacter bacterial species) and sensitive (95% probability of detecting 22 genome copies). A competitive internal amplification control (IAC) has been incorporated to give unambiguous determination of negative results. Immunoseparation of Campylobacter allows direct LAMP detection from poultry boot swab samples in 90 min without enrichment or DNA purification (74% probability of detecting 10(4) CFU ml(-1) of a boot swab suspension). The analysis of 17 samples from commercial turkey farms showed 100% correlation with parallel results obtained by standard microbiological methods.

Conclusions: A rapid test has been developed for direct detection of thermotolerant Campylobacter spp. in boot swab samples, thus bypassing culture enrichment or DNA extraction. The test has potential to be carried out by farm personnel on site.

Significance and impact of the study: The method offers an inexpensive approach to monitor poultry infection in near real time, assisting flock management and controls to prevent introduction of Campylobacter into the food chain.

Keywords: Campylobacter; LAMP; detection; food safety; internal amplification control; poultry.