Campylobacteriosis is the most frequently reported bacterial food-borne illness in EU. The aim of the study was to evaluate real-time PCR (qPCR) and digital PCR (dPCR) for quantification of Campylobacter jejuni in broiler neck-skin samples collected from a poultry slaughterhouse, and to compare them with the ISO 10272-2 standard plate count method. Results showed that qPCR exhibited good performance with the reliable limit of detection (rLOD) and limit of quantification (LOQ) reaching the theoretical limits. However, both rLOD and LOQ were beyond the EFSA-proposed critical limits for C. jejuni contamination of poultry skin and a modification of the procedure is suggested to include less sample dilution prior to DNA extraction. A strong and statistically significant correlation was observed between qPCR and dPCR. Both PCR-based methods correlated significantly with the plate count method; however, the correlation was moderate. A significant bias toward overestimation in dPCR was observed, probably due to the relatively high number of false positive calls. The linear dynamic range was comparable in both PCR-based methods; however, qPCR proved to be more suitable for routine use.
We defined anti-Campylobacter jejuni activity of an extract from waste skins and seeds of Pinot noir grapes (GSS), resveratrol and possible resistance mechanisms of C. jejuni using gene-specific knock-out mutants and efflux pump inhibitors. We showed CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene surface and selected human and animal cell lines, GSS extract shows an efficient inhibition of adhesion of C. jejuni to these abiotic and biotic surfaces. An understanding of the activities of natural compounds as bacterial growth inhibitors, mechanisms of these activities and bacterial resistance is crucial for further steps towards the application of new innovative strategies to control Campylobacter contamination in the food chain.
The antimicrobial, antibiofilm and antiquorum sensing properties of the Euodia ruticarpa fruit extract (EREE) and its fractions (fraction Q, evodiamine, rutaecarpine) were tested on C. jejuni NCTC 11168 and its mutants cmeB and luxS, on stainless steel surface. Respectively, EREE and fraction Q (with 41.7% share of evokarpina) showed the highest antibiofilm and antiquorum sensing potential. The study gives us guidelines for further research of biofilms and the emergence and spread of resistance to existing antimicrobials of C. jejuni in the search of alternative compounds of natural origin.