Selective Medium for Aerobic Incubation of Campylobacter

Abstract

The objective of this study was to examine the efficacy of three antibiotic mixtures for use as supplements in a selective medium that could be used to isolate Campylobacter from mixed bacterial cultures during aerobic incubation. A non-selective, basal broth medium was prepared and supplemented with Bolton, Cefex, or Skirrow antibiotic mixtures. The ability of pure cultures of Campylobacter coli, Campylobacter fetus, Campylobacter jejuni, and Campylobacter lari to grow in basal broth and basal broth supplemented with each one of the antibiotic mixtures after aerobic incubation for 24 and 48 h at 37°C was determined. Also, the ability of pure cultures of Escherichia coli, Enterococcus faecalis, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Kentucky, and Staphylococcus aureus to grow in basal and supplemented broth medium was determined. Additionally, the recovery of bacteria from mixed cultures containing one Campylobacter isolate with the other 6 non-Campylobacter isolates after aerobic incubation for 48 h at 37°C in basal broth and broth supplemented with the Bolton antibiotic mixture was examined. Results indicated that there was significant (p ≤ 0.05) growth of most Campylobacter isolates in basal broth and in broth supplemented with Bolton, Cefex, or Skirrow antibiotic mixtures after 24 or 48 h of aerobic incubation. Although, there was significant growth non-Campylobacter isolates in basal broth, growth of most these bacteria was inhibited in media supplemented with antibiotic mixtures. Also, Campylobacter growth was generally significantly less than other bacteria in mixed bacterial cultures grown in basal broth for 48 h at 37°C, but significantly more of most Campylobacter isolates were recovered from mixed bacterial cultures grown in media supplemented with the Bolton antibiotic mixture. Findings indicate that basal medium containing this supplement should be studied as a selective medium that may be utilized with aerobic incubation to isolate Campylobacter from environmental samples containing other bacteria.