'DNA' as contaminants in antibiotics and its capacity to transform bacteria to drug resistance.

DNA/and deoxyribose sugars were detected in streptomycin (Sm), kanamycin, polymyxin, penicillin G, ampicillin, methicillin, cloxacillin and mitomycin C in small amounts/traces. Stained DNA could be feebly visualized directly in Sm run in agarose gel, which improved after its separation and concentration. These DNA materials were DNase sensitive, RNase and pronase resistant, and appeared to consist of fragments, c. less than or equal to 6 Mdal; this could repeatedly transform to SmR several recipient enterobacteria and vibrios; E. coli C600 and S. typhi 57, after such transformation revealed similar plasmid DNA bands that were absent in their wild-types. G + C mole% of plasmid and chromosomal DNA of recipient (57) along with that of Streptomyces griseus reference strain, suggested an extraneous origin for the plasmid DNA.