A Modified Broth-Disk Antibiotic Susceptibility Test for

A broth-disk method for determining the antibiotic susceptibility of Campylobacter species was studied. The broth-disk method used to test anaerobes was modified for testing the antibiotic susceptibility of Campylobacter jejuni in an aerobic atmosphere. The basal medium of the test consisted of Brucella broth with 0.13 % agar and contained a ferrous iron, sodium pyruvate, sodium bisulfite supplement. Antibiotic disks were added to the tubed medium to approximate the minimal inhibitory concentration (MIC) breakpoint values for susceptibility. The antibiotic susceptibilities of 29 strains of Campylobacter fejuni to seven antibiotics were tested by the broth-disk method and the results compared with the MIC values determined by agar dilution. The broth-disk results were reproducible and agreed with approximately 90-100 % of the MIC determinations. This broth-disk method appears to be a reliable, simple, and inexpensive method for testing antibiotic susceptibility of Campylobacter species.