Development of a new protocol for the isolation and quantification of Arcobacter species from poultry products

None of the presently available selective supplements for the specific isolation of Arcobacter species allows the growth of Arcobacter butzleri, A. cryaerophilus and A. skirrowii and at the same time fully suppresses the accompanying flora present in poultry and poultry products. Furthermore, little is known about the contamination levels of poultry with Arcobacter species. In this study, a new selective supplement comprising amphotericin B (10 mg/l), cefoperazone (16 mg/l), 5-fluorouracil (100 mg/l), novobiocin (32 mg/l) and trimethoprim (64 mg/l) was developed. With a new isolation procedure, including enrichment in Arcobacter broth with the selective supplement, incubated for 24 to 48 h at 28 degrees C under microaerobic conditions, arcobacters were isolated from 100% (n = 34) of neck skin of laying hens and from 90% (n = 71) of similar samples from broilers. Of the broiler breast meat samples examined (n = 52), 65% were found to be contaminated with these bacteria. In 64% of the samples, A. butzleri was the only Arcobacter species isolated. In 9% of the samples, A. cryaerophilus was the only species present, while 11% of the samples were positive for both species simultaneously. Using direct isolation on the selective agar medium developed in this study, incubated for 24 to 48 h under microaerobic conditions at 28 degrees C, 32 out of 45 broiler carcasses and 6 out of 25 broiler breast meat samples carried a bacterial load of arcobacters of 10(2) to 10(3) cfu/g. The prevalence of Arcobacter in Belgian poultry was found higher than the prevalence of thermophilic Campylobacter species in each of the poultry categories examined. The enrichment procedure and the direct plating method were validated for the isolation of A. skirrowii. For this species, growth performance was less than the other two Arcobacter species and it was not isolated nor detected by m-PCR from the naturally contaminated poultry samples examined. This new protocol provides a fast and reliable method for the isolation of Arcobacter species from poultry and can contribute to more comprehensive epidemiological investigations.