CRISPR systems provide transient immunity against phages
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB44752 | ENA |
REPOSITORIES: ENA
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Project description:Clinical case studies have reported that the combined use of specific lytic phage(s) and antibiotics reduces the severity of difficult-to-treat Pseudomonas aeruginosa infections in many patients. In vitro methods that attempt to reproduce specific pathophysiological conditions can provide a reliable assessment of the antibacterial effects of phages. Here, we measured bacterial killing kinetics and individual phage replication in different growth phases, including biofilms, elucidating factors influencing the efficacy of two phages against the laboratory strain P. aeruginosa PAO1. While two-phage combination treatment effectively eliminated P. aeruginosa in routine broth and in infected human lung cell cultures, the emergence of phage-resistant variants occurred under both conditions. Phage combination displayed initial inhibition of biofilm dispersal, but sustained control was achieved only with a combination of phages and meropenem. In contrast, surface-attached biofilm exhibited tolerance to phage and/or meropenem, suggesting a spatiotemporal variation in antibacterial effect. Moreover, the phage with the shorter lysis time killed P. aeruginosa more rapidly, selecting a specific nucleotide polymorphism that likely conferred a competitive disadvantage and cross resistance to the second phage of the combination. These findings highlight biofilm developmental phase, inter-phage competition and phage resistance as factors limiting the in vitro efficacy of a phage combination. However, their precise impact on the outcome of phage therapy remains uncertain, necessitating validation through phage efficacy trials in order to establish clearer correlations between laboratory assessments and clinical results.
2024-07-17 | GSE271537 | GEO
Project description:Complete genomes of five Enterococcus faecium virulent phages targeting VRE isolates
| PRJEB41784 | ENA
Project description:This series represents the gene expression study of phages DT1 and 2972 during the whole process of infection. Gene expression was measured at nine time intervals (0, 2, 7, 12, 17, 22, 27, 32, 37 minutes) during phage infection.
2005-08-10 | E-GEOD-2476 | biostudies-arrayexpress
Project description:This series represents the gene expression study of phages DT1 and 2972 during the whole process of infection. Gene expression was measured at nine time intervals (0, 2, 7, 12, 17, 22, 27, 32, 37 minutes) during phage infection. Keywords: time-course
2005-08-10 | GSE2476 | GEO
Project description:Retrons are toxin-antitoxin systems protecting bacteria against bacteriophages via abortive infection. The Retron-Eco1 antitoxin is formed by a reverse transcriptase (RT) and a non-coding RNA (ncRNA)/multi-copy single-stranded DNA (msDNA) hybrid that neutralizes an uncharacterized toxic effector. Yet, the molecular mechanisms underlying phage defense remain unknown. Here, we show that the N-glycosidase effector, which belongs to the STIR superfamily, hydrolyzes NAD+ during infection. Cryoelectron microscopy (cryo-EM) analysis shows that the msDNA stabilizes a filament that cages the effector in a low-activity state in which ADPr, a NAD+ hydrolysis product, is covalently linked to the catalytic E106 residue. Mutations shortening the msDNA induce filament disassembly and the effector’s toxicity, underscoring the msDNA role in immunity. Furthermore, we discovered a phage-encoded Retron-Eco1 inhibitor (U56) that binds ADPr, highlighting the intricate interplay between retron systems and phage evolution. Our work outlines the structural basis of Retron-Eco1 defense, uncovering ADPr’s pivotal role in immunity.
2024-05-23 | PXD044835 | Pride