Bactericidal effect of 15-deoxyspergualin on Staphylococcus aureus

15-Deoxyspergualin (DSG), an immunosuppressive agent used in organ transplantation, exerts metabolic and antiproliferative effects on methicillin- and gentamicin-resistant Staphylococcus aureus and other bacteria (e.g. Sarcina lutea, Bacillus subtilis, Shigella sonnei, Salmonella typhi and Citrobacter freundii). DSG, at the concentration of 20 mg/l, depleted intracellular putrescine and spermidine in S. aureus to 43 and 40% of the controls, respectively. In these polyamine-depleted S. aureus cells, the synthesis of protein, DNA and RNA was decreased to 20, 85, 78% of the controls. The minimal inhibitory concentrations (MIC) of DSG for growth of S. aureus, S. lutea, B. subtilis, S. sonnei, S. typhi and C. freundii were 17, 13, 7, 15, 4, and 29 mg/l, respectively.