[Biological properties of Salmonella typhimurium mutants with an altered sensitivity to erythromycin].

S. typhimurium mutants with altered sensitivity to erythromycin (more resistant or more sensitive than the original culture) were selected. Some of the properties of the mutants studied were found to be changed: morphology, character of growth in the liquid nutrient medium with aeration (increased generation time and number of generations in log-period), sensitivity to ionic detergent--sodium dodecyl sulfate (its decrease). Some of the mutants acquired cross resistance or sensitivity to other antibiotics. The mutants studied had decreased virulence for albino mice. As the mutants were selected by increased resistance or sensitivity to erythromycin, which acted upon the 50 S ribosomal subunits, the pleiotropic changes of their properties were possibly due to some alterations in the ribosomes.