Frequency of occurrence of Campylobacter spp. in red meats and poultry in Northern Ireland and their subsequent subtyping using polymerase chain reaction-restriction fragment length polymorphism and the random amplified polymorphic DNA method.

Sampling of lamb (n = 100) and beef (n = 100) carcasses in abattoirs in Northern Ireland produced no evidence of Campylobacter spp. contamination and when retail packs of beef (n = 50) and pork (n = 50) were sampled these were also apparently free of Campylobacter spp. However, 38% of retail packs of chicken pieces (n = 120), yielded Campylobacter spp. These packs were purchased over a period of 1 year and came from a single local producer. After the species of the isolates had been determined (Campylobacter jejuni and Camp. coli were found in approximately equal numbers) they were subtyped using both polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and the random amplified polymorphic DNA (RAPD) method of typing. All of the poultry isolates were successfully typed by these methods, in contrast to the results obtained with serotyping where several isolates were found to be untypable. PCR-RFLP typing showed that specific subtypes were isolated repeatedly over a period of 1 year in the output of the producer studied. The more discriminating RAPD confirmed this observation, but with fewer isolates. This appears to indicate recurrent infection of broilers whose source can now be investigated using the methodologies developed.