Inhibition of Heniolytic Activity of El Tor Vibrio by Antibiotics Which Interfere with Protein Synthesis ∗

Summary

Exposure of the El Tor strain of V. cholera to antibiotics which interfere with protein synthesis was found to suppress the capacity of this organism to produce hemolysis. Inhibition of this effect appeared just prior to and in the early phase of decrease in the numbers of bacteria. Inhibition of hemolysin production was related to the concentration of antibiotic and the time over which the organism remained in contact with it. Antimicrobial agents which act by interfering with cell wall synthesis or alter the integrity of cell membranes did not decrease hemolysin production; penicillin and cephalo thin appeared to increase it. The addition of penicillin to tetracycline or chloramphenicol reduced the hemolytic inhibitory activity of these compounds. Combining cephalothin with these broad-spectrum antibiotics shortened the time required for inhibition of hemolysis to develop.