Combining nuclear magnetic resonance and mass spectrometry metabolomics for infectious disease

Metabolomics has quickly gained interest due to its ability to probe and uncover biological perturbations. At the base of “omics” hierarchy, this technique is able of capturing the phenotypic state by probing an organism’s metabolites, which gives immediate feedback on genetic or environmental conditions. Metabolomics is examines virtually any biological sample. Thus, metabolomics can provide rapid insights on issues ranging from features like bacterial pathogenicity to drug resistances. This dissertation describes method development combining mass spectrometry (MS) and nuclear magnetic resonance (NMR), and its application to probe bacterial cell death in Staphylococcus aureus, investigation of bacterial resistance within MTB, and discovery of a mechanism of action for new antibacterial compounds. Currently, metabolomics datasets are primarily collected utilizing either MS or NMR. Both methods have many advantages, but also significant limitation. Consequently, individual application of MS or NMR observes a fraction of the entire metabolome. Since the two methods are fundamentally complementary, combining NMR and MS datasets, increasing metabolome coverage. Staphylococcus aureus is a versatile human pathogen responsible for a variety of infections ranging from folliculitis to severe sepsis, endocarditis and bacteremia. S. aureus infections represent an enormous challenge to physicians because of the emergence and dissemination of multidrug-resistant strains in the health-care setting. Ability of this bacterial pathogen to survive and efficiently colonize diverse host environments based on its proficiency to optimize virulence factor production and adjust its metabolism to rapid environmental changes. Pta-AckA pathway is a vital ATP generating pathway for S. aureus. Disruption of this pathway during overflow metabolism causes reduction in growth rate and viability but not due to intracellular ATP depletion. We demonstrate the toxicity associated with inactivation of this pathway is caused by redox imbalance. Tuberculosis (TB) remains one of the leading causes of morbidity and mortality from a single infectious disease. The emergence of MDR-TB and XDR-TB strains threatens efforts in disease control. Currently, 3.7% of new TB patients are infected with MDR-TB. A better understanding of the molecular mechanisms of action and resistance to existing antibiotics, and the development of novel drugs more potent and safer is needed