Drug Resistance of Staphylococci VII. Genetic Determinants Responsible for the Resistance to Tetracycline, Streptomycin, Sulfanilamide, and Penicillin

Abstract

A genetic analy-sis of resistance to tetracycline (TC), streptomycin (SM), sulfanila-mide (SA) and penicillin G was carried out through transduction with phage lysates obtained from a multiply resistant strain of Staphylococcus aureus by UV irradiation. All transductants acquired resistance to both TC and SA, even when singly selected for either SA or TC resistance. The locus responsible for TC resistance could not be separated genetically from that for SA resistance. In transduction of SM resistance, about 30% of the transductants jointly acquired resistance to both TC and SA. These observations suggest that the loci governing resistance to TC, SA and SM exist close together on a single genetic unit, this probably being the chromosome.