Effect of enzyme I of the bacterial phosphoenolpyruvate : sugar phosphotransferase system (PTS) on virulence in a murine model.

The phosphoenolpyruvate : sugar phosphotransferase system (PTS) catalyses translocation with concomitant phosphorylation of sugars and hexitols and it regulates metabolism in response to the availability of carbohydrates. The PTS forms an interface between energy and signal transduction and its inhibition is likely to have pleiotropic effects. It is present in about one-third of bacteria with fully sequenced genomes, including many common pathogens, but does not occur in eukaryotes. Enzyme I (ptsI) is the first component of the divergent protein phosphorylation cascade. ptsI deletions were constructed in Salmonella typhimurium, Staphylococcus aureus and Haemophilus influenzae and virulence of the mutants was characterized in an intraperitoneal mouse model. The log(attenuation) values were 2.3, 1.4 and 0.9 for the Sal. typhimurium, Sta. aureus and H. influenzae ptsI mutants, respectively. The degree of attenuation is correlated with the complexity of the respective PTS, which comprises approximately 40 components in Sal. typhimurium, but only 5 in H. influenzae.