Untargeted LC-MS-based metabolic fingerprinting of Escherichia coli-associated urinary tract infections and urosepsis: Insights into the urine, serum, and bacterial interactomes

Urinary tract infections (UTIs) and urosepsis necessitate a deeper understanding of host-pathogen interactions at the metabolic level. We use LC-MS and GC-MS techniques to characterize metabolic pathway alterations in patients and Escherichia coli isolates during UTI and urosepsis. Our findings reveal substantial metabolic adaptations in the human host, including increased porphyrin metabolism, suggesting oxidative stress response or tissue damage. Activation of the pentose phosphate pathway (PPP) and tricarboxylic acid cycle (TCA) highlights the host's heightened immune and energy demands during infection. Additionally, enhanced malate-aspartate shuttle activity suggests a greater reliance on glycolysis for energy production, while increased pyruvaldehyde degradation indicates active detoxification of harmful metabolic byproducts. In E. coli, distinct metabolic shifts depended on the extracellular/intracellular niche and infection stage. Intracellular metabolites of E. coli during urosepsis exhibited upregulated purine and biotin metabolism, reflecting a focus on replication and essential metabolic functions. Conversely, intracellular metabolites of E. coli during UTI displayed increased aspartate metabolism, TCA cycle activity, Warburg effect, fatty acid biosynthesis, and glycine/serine metabolism, indicative of urinary tract adaptation. Extracellular metabolites of E. coli during urosepsis exhibited a broad activation of sugar metabolism, highlighting its ability to exploit diverse nutrient sources in systemic infection. In contrast, extracellular metabolites of E. coli during UTI demonstrated specific metabolic changes, including propanoate metabolism activation and homocysteine dysregulation, reflecting unique urinary tract conditions. These findings provide insights into the metabolic pathways employed by host and pathogen during UTI and urosepsis, uncovering potential metabolic vulnerabilities in E. coli.