Development of a new medium for the isolation of Arcobacter spp

• Published in: Journal of food protection Vol. 62; no. 5; pp. 456 - 462
• Main Authors: Johnson, L.G, Murano, E.A
• Format: Journal Article
• Language: English
• Published: Des Moines, IA International Association of Milk, Food and Environmental Sanitarians 01.05.1999
• Subjects: Action of physical and chemical agents on bacteria; Aerobiosis; anatomy and morphology; Anti-Bacterial Agents - pharmacology; Arcobacter; Bacteriology; Biological and medical sciences; Campylobacter; Campylobacter - drug effects; Campylobacter - growth & development; Campylobacter - isolation & purification; Colony Count, Microbial; culture media; Culture Media - chemistry; Evaluation Studies as Topic; Food industries; Food microbiology; Food toxicology; foods; Fundamental and applied biological sciences. Psychology; Gram-Negative Bacteria - drug effects; Gram-Negative Bacteria - growth & development; Gram-Negative Bacteria - isolation & purification; Helicobacter; identification; isolation; Microbial Sensitivity Tests; Microbiology; nutrient availability; pathogens; species differences; Culture medium; Aerobiosis; Campylobacteraceae; Selectivity; non-spore forming strains; Reducing agent; Antibiotic; Pathogen strain; Bacteria; Isolation; Identification test; Public health; Microaerophily; Campylobacter
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-62.5.456

Arcobacter, the newly reclassified Campylobacter species, has been shown to cause diarrhea in both humans and animals. Few studies have been conducted regarding its occurrence in foods because of the lack of effective isolation and identification methods. The purpose of this study was to develop a plating medium 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 was examined. These components were divided into five distinct groups: (1) basic growth nutrients, (2) reducing and growth-promoting agents, (3) detoxifying agents, (4) antibiotics, and (5) color-enhancing compounds. Components from each of these groups were tested for their ability to recover Arcobacter on a solid medium when incubated aerobically at 30 degrees C for up to 72 h. Growth was evaluated by the ecometric technique, colony size, and differential colony morphology after incubation. After initial evaluations, five formulas showing the best results were selected and tested in detail and compared with brucella agar. A medium containing a basal nutrient mix along with 0.05% thioglycolic acid, 0.05% sodium pyruvate, and 5% sheep's blood (pH 6.9 +/- 0.2) was found to be the most effective for the growth of A. butzleri, A. cryaerophilus, and A. nitrofigilis. In addition to superior growth characteristics, a deep red color around the colonies also was observed with this formulation.