CHARACTERISTICS OF A HIGH FREQUENCY OF RECOMBINATION (HFR) STRAIN OF SALMONELLA TYPHOSA COMPATIBLE WITH SALMONELLA, SHIGELLA, AND ESCHERICHIA SPECIES

Abstract

A lac+ strain of Salmonella typhosa, ST-2, was shown to be capable of recombination with lac cultures of diverse species of enteric bacteria. Lac+ hybrids were found to have acquired the ability to mate as males. The ST-2 strain appears to act as a typical Hfr culture, giving a high frequency of detectable recombinants and being unable to transfer the fertility factor F by contact. It can, however, transfer the Hfr character to recipient strains of diverse species via hybridization. These hybrids can in turn act as donor strains, usually with the same high frequency of recombination as strain ST-2.