Colistin sulfate as a suitable substitute of thallium acetate in culture media intended for mycoplasma detection and culture.

Thallium acetate in concentrations of 500 to 1000 mg/l is tolerated in the culture by the most mollicutes of the orders Mycoplasmatales and Acholeplasmatales and by this reason it is added in the culture media as a selective element for the detection and propagation of mycoplasmas and acholeplasmas. Because of the high toxicity of thallium acetate and its accumulation in the environment, thallium acetate is not biodegradable, an alternative was searched. The results and analysis of tests with nine mollicute species are presented here. It is recommended to replace thallium acetate in the formulations where it is used and colistin sulfate is proposed as its substitute.