Project description:Antibiotic use can lead to expansion of multi-drug resistant pathobionts within the gut microbiome that can cause life-threatening infections. Selective alternatives to conventional antibiotics are in dire need. Here, we describe a Klebsiella PhageBank that enables the rapid design of antimicrobial bacteriophage cocktails to treat multi-drug resistant Klebsiella pneumoniae. Using a transposon library in carbapenem-resistant K. pneumoniae, we identified host factors required for phage infection in major Klebsiella phage families. Leveraging the diversity of the PhageBank and experimental evolution strategies, we formulated combinations of phages that minimize the occurrence of phage resistance in vitro. Optimized bacteriophage cocktails selectively suppressed the burden of multi-drug resistant K. pneumoniae in the mouse gut microbiome and drove bacterial populations to lose key virulence factors that act as phage receptors. Further, phage-mediated diversification of bacterial populations in the gut enabled co-evolution of phage variants with higher virulence and a broader host range. Altogether, the Klebsiella PhageBank represents a roadmap for both phage researchers and clinicians to enable phage therapy against a critical multidrug-resistant human pathogen.
Project description:Contrasting effects of historical contingency on phenotypic and genomic trajectories during a two-step evolution experiment with bacteria
| PRJEB13018 | ENA
Project description:Compensatory evolution in populations with fixed or non-fixed antibiotic resistance
| PRJNA910842 | ENA
Project description:Historical contingency impacts community assembly and ecosystem function in sulfidic marine ecosystems
Project description:Pseudomonas syringae pv. phaseolicola (Pph) is a significant bacterial pathogen of agricultural crops, and phage Φ6 and other members of the dsRNA virus family Cystoviridae undergo lytic (virulent) infection of Pph, using the type IV pilus as the initial site of cellular attachment. Despite the popularity of Pph/phage Φ6 as a model system in evolutionary biology, Pph resistance to phage Φ6 remains poorly characterized. To investigate differences between phage Φ6 resistant Pseudomonas syringae pathovar phaseolicola strains, we performed expression analysis of super and non piliated strains of Pseudomonas syringae to determine the genetic cause of resistance to viral infection.
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.