[Genetic determinants of the O-antigens of serologically typed E. coli].

A study was made of the genetic determinants of the O-antigenicity in the E. coli, O25 and O86 serological groups in experiments on conjugation and transduction. In analysis of genetic recombinants selected from the crosses of the serologically typed and nontyped bacteria there was revealed a relationship between the inheritance of the antigenic signs (O25+ and O86+) and the capacity of histidine to synthesis. The S-form and the O25-antigenicity signs were readily cotransduced with the his+ marker, this pointing to the close linking of the corresponding genes loci on the bacterial chromosome.