Natural in vivo transfer of infectious drug resistance in the calf

Abstract

Extract

Sir,—Infectious drug resistance in the Enterobacteriaceae can be transferred in vitro and in vivo. In vivo transfer has been demonstrated in a germ free mouse (Kasuya, 1964), conventional mice fed antibiotics (Kasuya, 1964; Guinée, 1965), and in newly-hatched chickens fed a conventional antibiotic-free ration (Walton, 1966). The majority of the above animal transfer experiments were carried out using laboratory prepared mutant Enterobacteriaceae as donor and recipient strains. Where field strains were used, transfers were not necessarily carried out in the animal species' from which the donor and recipient organisms were derived.