%0 Journal Article %A Sompolinsky, D. %A Zaidenzaig, Y. %A Ziegler-Schlomowitz, Ruth %A Abramova, Nili %T Mechanism of Tetracycline Resistance in Staphylococcus aureus %D 1970 %J Microbiology, %V 62 %N 3 %P 351-362 %@ 1465-2080 %R https://doi.org/10.1099/00221287-62-3-351 %I Microbiology Society, %X SUMMARY: Resistance of Staphylococcus aureus m to tetracycline was due to an extrachromosomal genetic unit (plasmid) that could be eliminated by growth at 44°. The susceptible (eliminated) strain actively concentrated tetracycline from the nutrient medium by an energy-dependent transport system. The resistant culture accumulated the drug to a much lesser degree than the susceptible culture, both according to the E 380 of the bacterial extract and to its radioactivity after incubation with tritiated tetracycline. Accumulation of tetracycline was low and independent of the external concentration until this reached a level corresponding approximately to the minimal inhibitory concentration. Pre-incubation with tetracycline at low concentrations decreased ability to accumulate the drug. This pre-incubation effect was not prevented by nalidixic acid but was by actinomycin D. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-62-3-351