Tracing flock-related Campylobacter clones from broiler farms through slaughter to retail products by pulsed-field gel electrophoresis

A total of 237 Campylobacter isolates from broiler flocks at farm (45 isolates) and slaughter (192 isolates) were typed by pulsed-field gel electrophoresis (PFGE) for epidemiological tracing studies. For PFGE, a modification of the Campynet method was used, which was standardized in a European Union project. The goal of the study was to trace flock-related Campylobacter clones through the whole production chain, from farm through slaughter to retail products, to investigate the introduction of thermophilic Campylobacter spp. on incoming contaminated carcasses during processing to the final products. The results of this study showed that identical clones of this pathogen, which had previously been found within the flocks during primary production, were also detected at individual stages of processing, including final products, which were packed and ready for sale. Most of the detected clones dominated during primary production and at slaughter. This study found PFGE to be suitable for examining epidemiological field data in the same region and time contexts. The discriminatory power of SmaI restriction enzyme digestion was sufficient. Relationships of the isolated Campylobacter strains could be confirmed by use of a second restriction enzyme, KpnI.