Can a visual loop-mediated isothermal amplification assay stand out in different detection methods when monitoring Campylobacter jejuni from diverse sources of samples?

Abstract

Consumption and exposure to Campylobacter-contaminated food are important causes of bacterial diarrhea. This paper reports the development and evaluation of a visual loop-mediated isothermal amplification (LAMP) assay targeting the highly conserved cjaA gene of Campylobacter jejuni (C. jejuni). This assay could be used for specialized detection and primary screening of retail food samples in China. When applied to 475 different samples, PCR (14.9%) and bacterial culture (12.7%) showed lower detection rates than the LAMP, which demonstrated 51 positive (16.6%) with a 100% diagnostic sensitivity to bacterial culture with no targets undetected. When tested with samples that had different cleanliness, the specificity (0.955), accuracy (0.961), positive likelihood ratio (22.417), kappa coefficient (0.844) for retail food samples tested by LAMP were higher than for fecal and environmental samples. Moreover, when tested with food samples that had different C. jejuni carry rates, LAMP was more sensitive in monitoring raw pork meat samples-the specificity (0.958), accuracy (0.958), and positive likelihood ratio (23.600) were higher than for chicken samples compared with a bacterial culture. The LAMP test enables the cost-effective detection of C. jejuni in food samples in 40 min, and it can also function as a primary screening approach or a complementary method in large-scale and on-site assays of food.