MECHANISM OF EMERGENCE OF RESISTANCE TO STREPTOMYCIN OF H. PERTUSSIS AND H. PARAPERTUSSIS DURING TREATMENT WITH THIS ANTIBIOTIC

Abstract

In large populations of H. pertussis and H. parapertussis which have never been exposed to streptomycin, it is possible to demonstrate the presence of cells resistant to streptomycin 1000 mcg./cc. These highly resistant cells exhibit the following traits which are characteristic of mutants: 1. Irregular occurrence in different independent cultures of same population size and strain and therefore independence of the action of streptomycin. 2. Transmission of the resistant trait unchanged in degree through many subcultures in the absence of streptomycin and, therefore, inheritance of the trait. 3. A rate of occurrence consistent with mutation frequency; the mutation rate of cells resistant to 1000 mcg./cc. does not differ significantly between these two species.