Nakae M, Inoue M, Mitsuhashi S
Antimicrob Agents Chemother. 1975 May;7(5):719-20. doi: 10.1128/AAC.7.5.719.
Ten strains of beta-hemolytic streptococci were tested for elimination of resistance to macrolide antibiotics, tetracycline, and chloramphenicol. Six of the strains lost resistance after cultivation at 41 C or addition of acriflavine (0.2 mug/ml). These results suggest that determinants governing resistance to these antibiotics are located on extrachromosomal genetic elements (plasmids) that are widely distributed in streptococci.