Minimum inhibitory concentrations of tetracycline to 256 tetracycline-resistant strains ofStaphylococcus aureuswere determined. M.I.C.'s tetracycline were appreciably higher among mercury resistant than among mercury sensitive strains.Mercury resistant strains representing various M.I.C.'s tetracycline grew significantly better in peptone water containing a therapeutic concentration of tetracycline than mercury sensitive strains representing the same range of resistance. The experiment was repeated after both groups had been adapted—or ‘trained’—to grow on agar containing tetracycline, 100µg./ml. The mercury sensitive strains now grew better than the mercury resistant group.The significance of these findings is discussed. It is concluded that tetracycline resistance is more stable and efficient in mercury resistant strains, and that it is probably genetic in origin—the result of mutation and selection. Tetracycline resistance in mercury sensitive strains is possibly the result of ‘training’.The associations and significance of both mercury resistance and tetracycline resistance inStaphylococcus aureusare discussed.
Batten 1969), there is a possibility that the relapse rate folowing relatively short courses of treatment with rifampicincontaining regimens might be lower than has been obtained with other drugs. This possibility is under current study in East Africa. REFERllNCES UaltmJ C (1969) Tubercle (Lond.) 50, 294 Di9l3 G, YsA1,W. S0C, J, le Lirzon M & ca4iG19 0ii)Rev. Tiberc. (Paris) 33,751 DI#d"WJM4G'A & Mitckison D A (t*1E)Tabwhk .)O, 351 Di M_ msaD A (1970) Tubercke (Lond.) 51, 389 DseuwRA(19Sb)t.diPho. 15, 263 EmeIAR5sa~I _IH~MuiIchl Rearcb Council (1966)Thb4k(Luwid)47, 1 (196{Thbercte(Lend.)#, 136 (190aThercl(Lod.):S1 1 (1Vt~)fl6ercie(Load.)5,l 123 _et*9(190)ThbWrcktLon.) SO, 12 S 1thui s aisTehWaloeis (W)uIira. Lie. The. 34l 80
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