Streptococcus pneumoniae and Staphylococcus aureus pneumonia induce distinct metabolic responses

Pneumonia is an infection of the lower respiratory tract caused by microbial pathogens. Two such pathogens, Streptococcus pneumoniae and Staphylococcus aureus, are the most common causes of community-acquired and hospital-acquired pneumonia respectively. Each expresses strains highly resistant to penicillin and other antibiotics, and a significant number of people succumb to infection by these pathogens every year. Urinary metabolite changes in a C57Bl/6 mouse model with lung infection from either S. pneumoniae or S. aureus were characterized using multivariate targeted profiling data obtained from (1)H NMR spectra. Marked changes in the urinary metabolite profile occurred within 24 h after infection with either pathogen. Specifically, significant decreases in TCA cycle intermediates, coupled with increases in fucose, creatine, and taurine were observed in the urine of S. pneumoniae-treated mice. Infection with S. aureus resulted in the decrease of a number of urinary metabolites including 1-methylnicotinamide, 3-methyl-2-oxovalerate, 2-oxoisocaproate, N-isovaleroylglycine and others. Disturbances in gut-derived microbial metabolites were also observed. Analysis of metabolic trajectory data indicated that, as the mice recovered from infection, their urinary metabolic profile became similar to that of the preinfected state. These results underline the potential of metabolomics as a tool for diagnosis, health monitoring, and drug development, and show its usefulness for understanding microbial-host interactions.