Project description:The antibiotic fosfomycin is widely recognized for treatment of lower urinary tract infections caused by Escherichia coli and lately gained importance as a therapeutic option to combat multidrug resistant bacteria. Still, resistance to fosfomycin frequently develops through mutations reducing its uptake. Whereas the inner membrane transport of fosfomycin has been extensively studied in E. coli, its outer membrane (OM) transport remains insufficiently understood. While evaluating minimal inhibitory concentrations in OM porin-deficient mutants, we observed that the E. coli ΔompCΔompF strain is five times more resistant to fosfomycin than the wild type and the respective single mutants. Continuous monitoring of cell lysis of porin-deficient strains in response to fosfomycin additionally indicated the relevance of LamB. Furthermore, the physiological relevance of OmpF, OmpC and LamB for fosfomycin uptake was confirmed by electrophysiological and transcriptional analysis. This study expands the knowledge of how fosfomycin crosses the OM of E. coli.
Project description:The emergence and spread of carbapenem-resistant Klebsiella pneumoniae (CR-KPN) infections have worsened the current situation worldwide. Clinically, cotrimoxazole (CTX) and amikacin (AMI) are considered to be the preferred drugs in the treatment of (CR-KPN). But for now, the extensive use of cotrimoxazole (CTX) and amikacin (AMI) During the course of treatment leads to the emergence of cotrimoxazole- and amikacin-resistant infections, which is of great clinical concern. Previous evidence has shown that bacteria with reduced metabolism tend to be resistant to antibiotics, however, the mechanism remains unclear. In the present study, proteomics was performed on the sensitive, cotrimoxazole-resistant, amikacin-resistant and cotrimoxazole/amikacin-both-resistant KPN clinical isolates, and 2266 proteins were identified in total by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) analysis. Further bioinformatic analysis showed down-regulation of tricarboxylic acid cycle pathway and up-regulation of alcohol metabolic or glutathione metabolism processes, which may contribute to ROS clearance and cell survival, in drug-resistant isolates. Finally, combined with minimum inhibitory concentration (MIC) of Amikacin and Cotrimoxazole on different KPN isolates, we identified nine proteins contributed mostly to such an alteration and the survival of bacteria under drug pressure, which could reveal novel mechanisms or pathways involved in drug resistance. These proteins and their pathways might be used as targets for the development of novel therapeutics against antimicrobial-resistant (AMR) infections.
Project description:The effectiveness of antibacterial agents is strongly influenced by its antibacterial mechanism, which, in turn, is dependent on the agent’s topological structure. In addition to oxidative stress (especially caused by reactive oxygen species), known to be a key mechanism for 2D phosphorene structures, physical penetration of bacterial cell membranes is predicted for violet phosphorene nanosheets. In this study, we demonstrate that violet phosphorus (VP) and its exfoliated product, violet phosphorene nanosheets (VPNS), have superior antibacterial capability against pathogens.A series of antibacterial tests and theoretical calculations show that VPNS can inactivate >99.9% of two common pathogens (Escherichia coli and Staphylococcus aureus) and >99% of two “superbugs” (i.e., antibiotic-resistant bacteria, Escherichia coli pUC19 and methicillin-resistant Staphylococcus aureus) via oxidative stress combined with cell membrane penetration by VPNS Moreover, VPNS have higher antibacterial activity than black phosphorene nanosheets in vitro and in vivo. We believe VPNS as special rigidly structured nanoagents have great potential for eradicating pathogens.
Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. In this study, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi-kinase inhibitor nintedanib. Using bulk and single-cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition.
Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. In this study, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi- kinase inhibitor nintedanib. Using single cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition.
Project description:Primary objectives: The study investigates whether a Escherichia coli Nissle-suspenison has a (preventive) antidiarrheal effect in patients with tumors who are treated with chemotherapeutic schemes which are associated with increased occurances of diarrhea. Diarrhea caused by treatment are thought to be reduced in intensity and/or frequency by the treatment with Escherichia coli Nissle-Suspension.
Primary endpoints: Common toxicity criteria (CTC) for diarrhea
Project description:In this work we describe a robust fosfomycin collateral sensitivity phenotype of Pseudomonas aeruginosa resistant mutants selected by antibiotics from different structural families. The underlying mechanism was the reduced expression of the genes encoding the peptidoglycan-recycling pathway, which preserves the peptidoglycan synthesis in situations where the de novo synthesis is blocked, and of fosA, encoding a fosfomycin-inactivating enzyme.
Project description:The purpose of this study is to determine whether the presence of pathogenic Escherichia coli in colon is associated with psychiatric disorders.
Project description:Staphylococcus aureus is a highly adaptable human pathogen; therefore a constant search for new effective antibiotic compounds is being preformed. Gene expression profiling can be used to determine potential targets and mechanisms of action (MOA) of known or potential drugs. The goal of our study was a development of a focused transcriptome platform to be used for confirming the MOA of new chemical entities which are designed as inhibitors of Mur ligases. A model transcriptional profile was set up for well described inhibitor of MurA ligase, fosfomycin. Moreover, we wanted to identify the pathways and processes primarily affected by this compound. S. aureus ATCC 29213 cells were treated with low concentrations of fosfomycin (1 and 4 µg/ml, respectively) and harvested at 10, 20 and 40 minutes after treatment, respectively. RNA was isolated, transcribed, labeled and hybridized to S. aureus GeneChips, representing approximately 3000 S. aureus genes. Using meta-analysis of our results and the results in the S. aureus microarray database, we have confirmed that fosfomycin induces âcell wall stimulonâ genes and were able to identify genes and pathways specifically modulated by fosfomycin. Time course, different fosfomycin concentration