Project description:Traditional vaccines are difficult to deploy against the diverse antibiotic-resistant, nosocomial pathogens that cause Hospital Acquired Infections (HAIs). We developed a unique, protein-free vaccine to present antibiotic-resistant HAIs. This vaccine protected mice from invasive infections caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, multidrug resistant Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Rhizopus delemar, and Candida albicans. Protection persisted even in neutropenic mice infected with A. baumannii or R. delemar. Protection was already apparent after 24 hours and lasted for up to 21 days after a single dose, with a second dose restoring efficacy. Protection persisted without lymphocytes but was abrogated with macrophages depletion. This vaccine induced trained immunity by altering the macrophage epigenetic landscape and the inflammatory response to infection.
Project description:The emergence of colistin resistance in carbapenem-resistant and extended-spectrum ß-lactamase (ESBL)-producing bacteria is a significant threat to human health, and new treatment strategies are urgently required. Here we investigated the ability of the safe-for-human use ionophore PBT2 to restore antibiotic sensitivity in several polymyxin-resistant, ESBL-producing, carbapenem resistant Gram-negative human pathogens. PBT2 was observed to resensitize Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa to last-resort polymyxin class antibiotics, including a ‘next generation’ polymyxin derivative, FADDI-287. To gain additional insight into the potential mechanism of action of PBT2, we analyzed the transcriptome of K. pneumoniae and E. coli in the presence of sub-inhibitory concentrations of PBT2. Treatment with PBT2 was associated with multiple stress responses in both K. pneumoniae and E. coli. Significant changes in the transcription of transition metal ion homeostasis genes were observed in both strains.
Project description:The emergence of polymyxin resistance in carbapenem-resistant and extended-spectrum -lactamase (ESBL)-producing bacteria is a critical threat to human health, and new treatment strategies are urgently required. Here, we investigated the ability of the safe-for-human use ionophore PBT2 to restore antibiotic sensitivity in polymyxin-resistant, ESBL-producing, carbapenem-resistant Gram-negative human pathogens. PBT2 was observed to resensitize Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa to last-resort polymyxin class antibiotics, including the less-toxic next-generation polymyxin derivative, FADDI-287. We were unable to select for mutants resistant to PBT2 + FADDI-287 in polymyxin resistant E. coli containing a plasmid-borne mcr-1 gene or K. pneumoniae carrying a chromosomal mgrB mutation. Using a highly invasive K. pneumoniae strain engineered for polymyxin resistance through mgrB mutation, we successfully demonstrated the efficacy of PBT2 + FADDI-287 in vivo for the treatment of Gram-negative sepsis. These data present a new treatment modality to break antibiotic resistance in high priority polymyxin-resistant Gram-negative pathogens.
Project description:The interactions between Gram-negative respiratory pathogens and the host environment at the site of infection largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to purified pulmonary surfactant (Survanta) through microarrays. This study provides novel insight into the interactions occurring between Gram-negative opportunistic pathogens and the host at an important infection site, and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactions in vitro. The goal of this study was to compare the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to pulmonary surfactant using a custom affymetrix chip designed for their genomes. The goal of this study was to compare the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to pulmonary surfactant using a custom affymetrix chip designed for their genomes.
2018-03-30 | GSE110628 | GEO
Project description:Carbapenemase gene environment of Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae
Project description:Objectives: This study aimed to investigate the microbiological characteristics of outer membrane vesicles (OMVs) derived from Pseudomonas aeruginosa (P. aeruginosa) to understand their mechanisms of inhibition of Acinetobacter baumannii (A. baumannii) in vitro. Methods: We assessed the inhibitory effects of P. aeruginosa on A. baumannii using a modified cross-streak assay. Subsequently, OMVs were extracted from P. aeruginosa strains using high-speed centrifugation, tangential flow filtration, ultrafiltration, and ultracentrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), transmission electron microscopy (TEM), and nanoparticle tracking assays (NTAs) were performed to confirm the presence of the extracted OMVs. P. aeruginosa-derived OMVs’ inhibitory activity against A. baumannii was tested using a modified time-kill assay. The proteomic analysis of OMVs revealed potential antibacterial protein clusters with diverse functions. Results: P. aeruginosa 022 (PA022) demonstrated inhibition of A. baumannii in the cross-streak assay. The protein levels of OMVs for PA022 and P. aeruginosa ATCC 27853 (PA ATCC 27853) were 1665 and 428.6 μg/mL, respectively. Additionally, PA 022 and PA ATCC 27853 exhibited variable patterns and sizes in the SDS-PAGE, TEM, and NTA. Furthermore, the growth inhibitory effect of PA022 OMVs on A. baumannii was evaluated using a modified time-kill assay. The proteomic analysis of OMVs revealed potential antibacterial protein clusters in PA 022 associated with virulence, motility, and post-translational modifications. Conclusion: Our study contributes to the understanding of P. aeruginosa OMVs characteristics and their inhibitory effect against A. baumannii, providing insights into the development of alternative therapeutic approaches against multi-drug resistance.
Project description:Current therapeutic strategies against bacterial infections focus on reduction of pathogen load using antibiotics; however, stimulation of host tolerance to infection in the presence of pathogens might offer an alternative approach. We used computational transcriptomics and Xenopus laevis embryos to discover infection response pathways, identify potential tolerance inducer drugs, and validate their ability to induce broad tolerance. Xenopus exhibits natural tolerance to Acinetobacter baumanii, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae bacteria, whereas Aeromonas hydrophila and Pseudomonas aeruginosa produce lethal infections. Transcriptional profiling led to definition of a 20-gene signature that discriminates between tolerant and susceptible states, as well as identification of a more active tolerance response to gram negative compared to gram positive bacteria. Gene pathways associated with active tolerance in Xenopus, including some involved in metal ion binding and hypoxia, were found to be conserved across species, including mammals, and administration of a metal chelator (deferoxamine) or a HIF-1 agonist (1,4-DPCA) in embryos infected with lethal A. hydrophila increased survival despite high pathogen load. These data demonstrate the value of combining the Xenopus embryo infection model with computational multi-omics analyses for mechanistic discovery and drug repurposing to induce host tolerance to bacterial infections.
Project description:Current therapeutic strategies against bacterial infections focus on reduction of pathogen load using antibiotics; however, stimulation of host tolerance to infection in the presence of pathogens might offer an alternative approach. We used computational transcriptomics and Xenopus laevis embryos to discover infection response pathways, identify potential tolerance inducer drugs, and validate their ability to induce broad tolerance. Xenopus exhibits natural tolerance to Acinetobacter baumanii, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae bacteria, whereas Aeromonas hydrophila and Pseudomonas aeruginosa produce lethal infections. Transcriptional profiling led to definition of a 20-gene signature that discriminates between tolerant and susceptible states, as well as identification of a more active tolerance response to gram negative compared to gram positive bacteria. Gene pathways associated with active tolerance in Xenopus, including some involved in metal ion binding and hypoxia, were found to be conserved across species, including mammals, and administration of a metal chelator (deferoxamine) or a HIF-1 agonist (1,4-DPCA) in embryos infected with lethal A. hydrophila increased survival despite high pathogen load. These data demonstrate the value of combining the Xenopus embryo infection model with computational multi-omics analyses for mechanistic discovery and drug repurposing to induce host tolerance to bacterial infections.
Project description:Using Nanopore sequencing, our study has revealed a close correlation between genomic methylation levels and antibiotic resistance rates in Acinetobacter Baumannii. Specifically, the combined genome-wide DNA methylome and transcriptome analysis revealed the first epigenetic-based antibiotic-resistance mechanism in A. baumannii. Our findings suggest that the precise location of methylation sites along the chromosome could provide new diagnostic markers and drug targets to improve the management of multidrug-resistant A. baumannii infections.