R. Pettit, G. Cage, G. Pettit
2000
Citations
0
Influential Citations
1
Citations
Quality indicators
Journal
International journal of antimicrobial agents
Abstract
The in vitro activity of the steroidal amide 3beta-acetoxy-17beta-(L-prolyl)amino-5alpha-androstane against 179 gram-positive clinical isolates was examined. The minimum bactericidal concentration (MBC)/MIC ratios were < or = 2 for 73% of methicillin-resistant Staphyllococcus aureus, 59% of vancomycin-resistant Enterococcus spp. and 88% of penicillin-resistant Streptococcus pneumoniae. The androstane derivative was bactericidal for a variety of other gram-positive genera, including Nocardia, Corynebacterium and Listeria. Variation in MICs is pH 6-8 media was slight. The frequency of occurrence of bacterial spontaneous mutations to resistance ranged from 10(-6) to 10(-9). Kill curve analysis confirmed the bactericidal nature of the steroidal amide, and demonstrated that killing was time dependent but not concentration dependent for all organisms. The ability of 3beta-acetoxy-17beta-(L-prolyl)amino-5alpha-androstane to inhibit human cancer cell growth was also evaluated. The concentration required to inhibit 50% of cell growth (GI50) was < 2.5 mg/l for all cell lines examined. In single-dose murine toxicity evaluations, the androstane derivative was non-toxic at doses up to 400 mg/kg.