Tropheryma whipplei the causative agent of Whipple disease, presents a diagnostic challenge due to its diverse symptomatology, including weight loss, abdominal pain, diarrhea, joint pain, fever, and occasionally neurological manifestations. Its resistance to fluoroquinolones complicates treatment further. Traditional methods for antibiotic susceptibility testing are ineffective as Tropheryma whipplei cannot be cultured in axenic media. To address this, we explored potential drug targets within its core genome as no drug targets from this bacterium have been studied so far. murE, a macrolide-resistant enzyme, emerged as a promising candidate exhibiting both resistance and drug target characteristics. We screened over 1,000 lead-like Ayurvedic compounds against the target enzyme UDP-N-acetylmuramyl-tripeptide synthetase and identified three promising candidates: (1) Ergost-5-en-3-ol (3beta,24xi), (2) [6]-Gingerdiol 3-monoacetate, and (3) Valtrate. DiffDock and GNINA rescoring yielded consistent binding strength rankings. Molecular dynamics simulations over 100 nanoseconds confirmed stable interactions with these compounds. ADMET analysis indicated low water solubility, but coupling with cyclodextrin SBE-β-CD improved solubility. None of the compounds showed hepatotoxic effects, though Valtrate exhibited AMES toxicity. Based on the favorable properties, we propose scaffold hopping and further in vitro/in vivo studies on [6]-Gingerdiol 3-monoacetate. Our findings offer potential avenues for combating T. whipplei infections, addressing the limitations posed by antibiotic resistance.

Background: Rickettsia typhi is the causative agent of epidemic murine typhus and Rocky Mountain spotted fever. The infection can affect multiple vital organs, including the heart, lungs, kidneys, and brain. Doxycycline is the recommended treatment but inflammation, mal-response, and drug resistance may arise. No natural product inhibitors have been reported against this bacterium. Aim: The objective of this study was to establish a potential connection between autoimmune disorders triggered by R. typhi, identify therapeutic targets within its core proteome, and explore novel natural product inhibitors from Streptomyces spp. that could potentially inhibit it. Methodology: Complete proteomes of four publicly available R. typhi strains were used for pan-proteomic analysis. The fni gene product (Isopentenyl pyrophosphate isomerase) was selected as the potential drug target. Molecular docking of 607 Streptomyces-derived metabolites was performed, with top hits validated using DiffDock and Vinardo scoring. Additionally, the Absorption, Distribution, Metabolism, Excretion, and Toxicity properties of the leading compounds were assessed via pkCSM, and formulation characteristics optimized using FormulationAI. Results: Out of the 803 core proteins, associations between 14 proteins were mined for autoimmune diseases (including psoriasis, rheumatoid arthritis, optic atrophy, uveitis, even-plus syndrome, Sjogren syndrome, inflammatory bowel disease, allergic rhinitis, systemic lupus erythematosus, sclerosis, Stevens-Johnson syndrome, toxic epidermal necrolysis, colitis etc.). 17 core proteins were predicted as druggable. ZINC01482946 demonstrated the strongest inhibitory potential, as confirmed by DiffDock scoring, convolutional neural network-based ranking, and Vinardo scoring. It demonstrated a stable configuration and exhibited a favorable pharmacokinetic profile, with bioavailability enhanced through cyclodextrin complexation. Conclusion: To the best of our knowledge, this is the first report identifying human autoimmune associations with R. typhi and natural product inhibitors targeting the pathogen. ZINC01482946 shows potential as an effective inhibitor of R. typhi, while SBE-β-CD appears to be a promising cyclodextrin for improving its solubility and bioavailability. Clinical trial number: Not applicable.