The development of an improved methodology for the detection of Arcobacter spp. in foods

Abstract

Members of Arcobacter, the newly reclassified icrographics. Campylobacter genus, have been shown to cause diarrhea in both humans and animals. In an effort to develop a better methodology to isolate Arcobacter from foods, a two phase study was conducted. The first phase was to develop a plating medials that would be selective for the three most commonly found Arcobacter species. The effect of common components used in media intended for the isolation of Campylobacter, Helicobacter, and other gram negative rods were examined for their effect on growth of these organisms. Components were evaluated for their ability to recover Arcobacter on a solid medium when incubated aerobically at 30OC for up to 7z11rs. After initial evaluations, five formulas which showed beneficial attributes, were selected and tested in detail and compared to Brucella agar for the growth of Arcobacter species. A medium containing a basal nutrient mix along with 0.05% thioglycolic acid, 0.05% sodium private, and 5% sheep's blood TH 6.910.2) was found to be the most effective in the growth of A. butzleri, A. cryaerophilus, and A. nitrohgilis. In addition to superior growth characteristics, a deep red color around the colonies was also observed with this formulation. In the second phase of this study, the aim was to develop a selective enrichment broth, comparing the efficacy of various selective agents and growth promoting additives at isolating three Arcobacter spp. This newly developed enrichment broth was incorporated into an isolation protocol using the plating medium developed in the first phase of this study. The effectiveness of this new protocol was compared with two existing methods for the isolation of Arcobacter in poultry. The new method isolated Arcobacter strains in 42 out of 50 broiler chicken samples, while the methods of Collins and deBoer detected the organism in only 24 and 15 samples, respectively.