Development of a novel visual detection technique for Campylobacter jejuni in chicken meat and caecum using polymerase spiral reaction (PSR) with pre-added dye

Rapid detection and efficient removal of Campylobacter jejuni contaminated chicken-based food products from the food chain have become decisive for preventing outbreaks. Here, we report a novel, rapid, simple and sensitive polymerase spiral reaction (PSR) assay for screening chicken samples for contamination of C. jejuni. Our method specifically amplified the hipO gene of C. jejuni and involved cost-effective three-step centrifugation method for DNA extraction and pre-addition of HNB dye for effortless visualization. PSR, real-time PCR and conventional PCR were able to detect 50 fg, 500 fg and 5 pg C. jejuni DNA per tube, respectively. In chicken meat and caecum, the detection limits of PSR without any enrichment, after including 12 h enrichment and 24 h enrichment steps were 16 ? 102 CFU/g, 160 CFU/g and 16 CFU/g, respectively which could be attained in 90 min, 13.5 h and 25.5 h, respectively. The field applicability of the PSR assay was evaluated through a field sampling study by testing 75 chicken meat and caecum samples. This assay permits timely reporting of results without the need of trained personnel and sophisticated equipments as it only relies on simple enrichment, water bath amplification and visual interpretation through colour change. This PSR assay can be a handy tool to screen C. jejuni contamination in chicken products and might subsequently help in reducing the incidence of foodborne C. jejuni infections. To our knowledge, this is the primary report to employ PSR for the detection of C. jejuni.