Escherichia coli resistance to various concentrations of streptomycin
Kynina, E.S.
Mikrobiolohichnyi Zhurnal 38(1): 44-46
1976
ISSN/ISBN: 0201-8462 PMID: 787731 Document Number: 102101
Various clones of the same strain of E. coli were passaged 18 times on the nutrient media with the presence of constant and increasing concentrations of streptomycin. The difference in sensitivity to streptomycin for various clones of the same strain was insignificant. With passages on the nutrient media containing streptomycin the difference in sensitivity to this antibiotics in various clones increased considerably; with constant concentrations of the antibiotic it was 40 times as high, and with increasing ones it was 128 times as high. Passages (18) of various clones of E. coli on the media with streptomycin resulted in a 4-fold decrease on the average for the level of their sensitivity in the presence of the antibiotic constant concentrations and in a 693-fold decrease in the presence of increasing concentrations. The increasing concentrations of the antibiotic, to a greater extent than the constant ones, promoted a rise in microorganism resistance to it in the process of passages in vitro.