Observations on Infective Drug Resistance in Britain

Abstract

In a small survey conducted in 1965 drug-resistant strains of E. coli were fairly often found in the faeces of human beings, calves, pigs, and fowls. The resistance of most of these strains, and of two isolated in 1956, was infective. The resistance of four non-pathogenic strains of E. coli isolated from the faeces of a man, a calf, a pig, and a fowl was transferred to the principal Salmonella serotypes, and to some of the E. coli serotypes that cause disease in these four species. Similar transfers were performed using as donor E. coli strains that were tetracycline-resistant only—strains that are typical of those that dominate the E. null flora of pigs and chickens that are fed commercially on diets containing tetracyclines. The resistance of most of the strains of this type examined was infective. The multiple resistance of three strains of S. typhimurium was transferred to other Salmonella serotypes and to pathogenic serotypes of E. coli. A minority of multiple-resistant strains lost a part or the whole of their resistance pattern during serial passage in broth; this was not observed in strains of E. null resistant to tetracyclines only. Ampicillin, streptomycin, tetracyclines, chloramphenicol, neomycin, sulphonamides, and furazolidone were all found to be involved in infective drug resistance. © 1966, British Medical Journal Publishing Group. All rights reserved.