[Transmissivity of the various R factors found among E. coli cultures circulating under natural conditions]

Transmissivity of drug resistance in wild strains of E. coli was shown to be determined not only by the presence of the transmissive factor and r-determinants in the microbial cell, but also by the functional activity of the R-factor. The capacity of the R-factor for transmission depended to a certain extent on the number of the r-determinants in the R-factor and the presence of various r-determinants in the R-factor.