J4-7608 — Final report
1.
New approaches on quantification of Campylobacter jejuni in poultry samples: the use of digital PCR and real-time PCR against the ISO standard plate count method

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.

COBISS.SI-ID: 4280442
2.
Anti-Campylobacter activity of resveratrol and an extract from waste Pinot noir grape skins and seeds, and resistance of C. jejuni planktonic and biofilm cells, mediated via the CmeABC efflux pump

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.

COBISS.SI-ID: 4699768
3.
Attenuation of adhesion, biofilm formation and quorum sensing of Campylobacter jejuni by Euodia ruticarpa

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.

COBISS.SI-ID: 4651384
4.
Population structure and attribution of human clinical Campylobacter jejuni isolates from central Europe to livestock and environmental sources

In this study we evaluated the role of agro-food industrial environment (including slaughtering) and natural environment (surface waters and wildlife) for transmission of C. jejuni to humans. We collected 410 isolates of C. jejuni from livestock, slaughterhouses, meat samples, environmental samples, and humans in central Europe. We first evaluated the source attribution potential of a six-gene multiplex PCR (mPCR) method coupled with STRUCTURE algorithm on a set of 410 C. jejuni. These C. jejuni isolates were previously characterized by multilocus sequence typing (MLST) demonstrating 74% congruence between mPCR and MLST groupings. The strains clustered into three genetically distinct groups, each correlated with its source of isolation, the first one associated with isolates from poultry, the second one with isolates from cattle, and the third one with isolates from the environment. The results indicated that the isolates form agro-food industrial environment present a frequent risk for human health, but only 7 % of human isolates were from environmental sources.

COBISS.SI-ID: 4777336
5.
Identification and characterization of pathogens of infectious disease with the method of next generation sequencing.

In the presentation, pathogen detection in complex samples by random shotgun sequencing, whole genome sequencing of economically important respiratory and enteric viruses and whole-genome sequencing of bacterial isolates were explained. Whole-genome sequencing enables the analysis of genetic traits of interest such as virulence and resistance determinants and genome-wide phylogenetic analysis.

COBISS.SI-ID: 4676474