| Abstract: | Staphylococcus aureus strains, resistant to actinomycin D (AMD) and to gramicidin S (GS) were selected by S. aureus 209P passing on the media containing the above mentioned drugs. Strain R80 resistant to AMD and strain R9 resistant to GS and AMD and described before didn't perform enzyme inactivation of AMD. Cells of both strains had diminished ability to bind exogenous AMD. Electron microscopy investigation revealed that cells of R80 strain had thickened cell walls and they are characterized by more electron density then cells of R9 strain and of parent strain. Adaption to AMD and GS influenced also on functions of some staphylococcal surface proteins--the activity of endogenous coagulase (clumping factor) was found only in R9 strain. Exogenous coagulase was present in all the strains, but development of resistant to AMD and GS diminished this enzyme activity. It is concluded that development of resistance to AMD and GS causes substantial changes in staphylococcal cell wall, but the type of these changes differ. |
