Ontology highlight
ABSTRACT:
PROVIDER: PRJNA755260 | ENA |
REPOSITORIES: ENA
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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.
2020-07-01 | GSE153553 | GEO
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.
2019-06-13 | GSE132637 | GEO
Project description:Background: It remains unclear how high-risk Escherichia coli lineages, like sequence type (ST) 131, initially adapt to carbapenem exposure in its progression to becoming carbapenem resistant. Methods: Carbapenem mutation frequency was measured in multiple subclades of extended-spectrum β-lactamase (ESBL) positive ST131 clinical isolates using a fluctuation assay followed by whole genome sequencing (WGS) characterization. Genomic, transcriptomic, and porin analyses of ST131 C2/H30Rx isolate, MB1860, under prolonged, increasing carbapenem exposure was performed using two distinct experimental evolutionary platforms to measure fast vs. slow adaptation. Results: All thirteen ESBL positive ST131 strains selected from a diverse (n=184) ST131 bacteremia cohort had detectable ertapenem (ETP) mutational frequencies with a statistically positive correlation between initial ESBL gene copy number and mutation frequency (r = 0.87, P<1e-5). WGS analysis of mutants showed initial response to ETP exposure resulted in significant increases in ESBL gene copy numbers or mutations in outer membrane porin (Omp) encoding genes in the absence of ESBL gene amplification with subclade specific adaptations. In both experimental evolutionary platforms, MB1860 responded to initial ETP exposure by increasing blaCTX-M-15 copy numbers via modular, insertion sequence 26 (IS26) mediated pseudocompound transposons (PCTns). Transposase activity driven by PCTn upregulation was a conserved expression signal in both experimental evolutionary platforms. Stable mutations in Omp encoding genes were detected only after prolonged increasing carbapenem exposure consistent with clinical observations. Conclusions: ESBL gene amplification is a conserved response to initial carbapenem exposure, especially within the high-risk ST131 C2 subclade. Targeting such amplification could assist with mitigating carbapenem resistance development.
2024-08-04 | GSE273456 | GEO
Project description:We generated a collection of 13 plasmids, with each plasmid containing a variant of a CRISPR protospacer targeted by spacer 8 of the E. coli CRISPR-I array. We transformed the plasmids as a pool into delta cas3 E. coli cells expressing all other cas genes constitutively. We then transformed these cells with either an empty vector or a plasmid expressing the Cas3 nuclease. DNA surrounding the protospacers was PCR-amplified and sequenced.
2017-08-24 | E-MTAB-5969 | biostudies-arrayexpress
Project description:We generated a collection of 13 plasmids, with each plasmid containing a variant of a CRISPR protospacer targeted by spacer 8 of the E. coli CRISPR-I array. We transformed the plasmids as a pool into delta cas3 E. coli cells expressing all other cas genes constitutively, with FLAG-tagged casA. We then used ChIP to enrich for CasA-bound protospacers. DNA surrounding the protospacers was PCR-amplified from input (pre-immunocrecipitation) and ChIP (post-immunoprecipitation) samples and sequenced.
2017-08-24 | E-MTAB-5972 | biostudies-arrayexpress
Project description:Chromosomes and plasmids are two forms of genetic carriers. Exogenous yeast artificial chromosomes are also considered as yeast centromeric plasmids in many cases. Here, we used state-of-the-art sequencing technologies to comprehensively profile the genetic, epigenetic, transcriptional and proteomic characteristics of an exogenous data-carrying chromosome. We found that the data-carrying DNA formed active chromatin with high chromatin accessibility and H3K4 tri-methylation levels. We also confirmed that the data-carrying chromosome had a circular shape in the nucleus and was arranged in the Rabl configuration, which may contribute to the self-replication and haploidy of the chromosome in vivo. The data-carrying chromosome displayed highly pervasive transcriptional ability and transcribed hundreds of non-coding RNAs. In summary, this work explores the chromatin epigenetic state, chromatin structure and transcriptional landscape of an exogenous artificial chromosome. The results demonstrated that the exogenous artificial chromosome did form a chromatin structure and was not a naked and incompact plasmid, which strengthen our understanding of artificial chromosomes.
2022-09-30 | GSE183491 | GEO
Project description:Bacterial defence systems are tightly regulated to avoid autoimmunity. In Type I restriction-modification (R-M) systems, a specific mechanism called restriction alleviation (RA) controls the activity of the restriction module. In the case of the Escherichia coli Type I R-M system EcoKI, RA proceeds through ClpXP-mediated proteolysis of restriction complexes bound to non-methylated sites that appear after replication or reparation of host DNA. Here, we show that RA is also induced in the presence of plasmids carrying EcoKI recognition sites, a phenomenon we refer to as plasmid-induced RA. Further, we show that the anti-restriction behavior of plasmid-borne non-conjugative transposons such as Tn5053, previously attributed to their ardD loci, is due to plasmid-induced RA. Plasmids carrying both EcoKI and Chi sites induce RA in RecA- and RecBCD-dependent manner. However, inactivation of both RecA and RecBCD restores RA, indicating that there exists an alternative, RecA-independent, homologous recombination pathway that is blocked in the presence of RecBCD. Indeed, plasmid-induced RA in a RecBCD-deficient background does not depend on the presence of Chi sites. We propose that processing of random dsDNA breaks in plasmid DNA via homologous recombination generates non-methylated EcoKI sites, which attract EcoKI restriction complexes channeling them for ClpXP-mediated proteolysis.
2024-06-23 | PXD050621 | Pride