The antibacterial potential of a phosphoenolpyruvate: Sugar phosphotransferase system blocking agent.

Abstract

The phosphoenolpyruvate:sugar phosphotransferase system (PTS) is involved in the transport and concentration of various carbohydrates across the plasma membrane of certain bacterial'.Since it is absent from eukaryotic cells, blockage of the PTS has been suggested as a potentially selective chemotherapeutic objective". The present study was undertaken to assess this possibili- The S. typhimurium strains used were the ptsHl deletion mutants SB2309 and SB2950, and the parent strain trpB22331. These cultures were maintained on nutrient agar slants. For in vitro growth studies, inocula were grown overnight at 37°C, with aeration, in Medium A, modified according to CORDARO and ROSEMAN31 and containing 0.2 % sodium lactate and 10 pg/ml tryptophan. A 1 % inoculum was used to initiate growth in Medium A containing 0.2 % glucose instead of lactate, tryptophan and varying concentrations of heat inactivated fetal calf serum (KC Biological, Inc., Lenexa, Kansas). These cultures were either aerated by bubbling, or alternatively, incubated under static conditions, in 16 x 100 mm test tubes, at 37°C. Growth was measured turbidometrically; generation times calculated from the linear portion of plots of log A600am vs. time are presented. For virulence tests, cultures were grown overnight, under static conditions, at 37°C, in trypticase soy broth (BBL, Div. Becton, Dickinson & Co., Cockeysville, Maryland) and dilutions were made in the same medium. Hog gastric mucin (ICN Pharmaceuticals, Cleveland, Ohio) was added, as indicated, to the appropriate serial dilution in trypticase soy broth to give a final concentration of 5 %. Swiss albino CD-1 mice weighing 18 -20 g were infected intraperitoneally with 0.5 ml of the appropriate inoculum. The LD50 (mean lethal dose) of each bacterial strain was determined 7 days after infection.