GENTAMICIN-RESISTANT MENADIONE AND HEMIN AUXOTROPHIC STAPHYLOCOCCUS-AUREUS PERSIST WITHIN CULTURED ENDOTHELIAL-CELLS

Staphylococcus aureus menadione and hemin auxotrophs, generated by in vitro gentamicin selection, demonstrated reduced hemolytic activity an d enhanced intracellular survival within cultured bovine aortic endoth elial cells relative to their hemolytic parent. Supplementation of the auxotrophs with exogenous menadione or hemin resulted in rapid growth , increased hemolytic activity, and reduced intracellular persistence to the level found for the hemolytic clinical parent. Aminoglycoside s election of staphylococcal menadione and hemin auxotrophs and subseque nt persistence of these variants in the intracellular milieu may adapt S. aureus for evasion of host defenses and resistance to antimicrobia l therapy.