Predominant strains of thermophilic Campylobacter spp. in a German poultry slaughterhouse

Campylobacter causes bacterial diarrhoea in man and is a common foodborne pathogen, that has been associated mainly with poultry carcasses and processed poultry products as well as with drinking water. Genotyping of Campylobacter spp. from poultry was done in order to prove if predominant stable strains in the food chain are present. The influence of the slaughter process on the stability should be determined. Thermophilic Campylobacter spp. from eight poultry flocks were isolated from cloacal swabs, carcasses and offal at different abattoir processing steps to determine their stability. DNA-fingerprinting was done using Pulsed-Field Gel Electrophoresis (PFGE) with two enzymes (SmaI and KpnI) and ribotyping. More than 150 Campylobacter strains were ribotyped and these data were combined with the results of PFGE. Molecular typing showed that strains found in cloacal swabs before processing could also be isolated from carcasses and offal at different processing steps representing predominating stable strains. Strains with varying molecular pattern could additionally be detected at different processing steps. Both genotyping methods identified in agreement flock-specific strains. These remained stable through the slaughter of poultry and were not altered through the slaughter process. Despite the known genetic variability of thermophilic Campylobacter, stable predominant strains could be identified in the poultry slaughter process and those strains can thus enter the food chain