Transduction Analysis of the Genetic Determinants for Chloramphenicol Resistance in Staphylococci

Abstract

A genetic analysis of resistance to chloramphenicol (CM) in Staphylococcus aureus S1337 was carried out through transduction. About 3 to 18% of the transductants jointly acquired resistance to both tetracycline (TC) and CM, even when singly selected for either CM- or TC-resistance. When singly selected for either TC- or streptomycin (SM)resistance, about 1 to 4% of the transductants jointly acquired resistance to both TC and SM. Joint transduction of both CM- and SM-resistance was never observed, when singly selected for either TC- or CM-resistance. These findings indicate that the genetic loci govering CM, TC and SM resistance in S1337 are closely linked, and appear to possess the following linkage order, -CM-TC-SM-. The finding that penicillin (PC) resistance is not cotransducible with either CM-, TC-, or SM-resistance, is also accordance with a previous result in MS27, indicating that PC-resistance is governed by a genetic unit different from the one carrying resistance to TC, SM and CM in S1337.