Speaker
Description
Phage-antibiotic combinations are a promising strategy to combat antimicrobial-resistant pathogens, but we currently lack mechanistic understanding of underlying bacterial responses. Here, we characterize the interaction between the antifolate antibiotic sulfamethoxazole and phage T4 in Escherichia coli.
We combine quantitative with molecular and phage biology approaches, namely checkerboard assays, time-lapse microscopy and one-step growth curves, to characterize phage-sulfamethoxazole interactions in E. coli.
Sulfamethoxazole protects bacterial cultures from rapid T4-induced collapse, even at subinhibitory concentrations. Checkerboard assays show similar effects with phage T2, but not phages T5 or T7. Preliminary single-cell time-lapse microscopy shows delayed cell lysis, suggesting slower propagation of infective progeny, which was confirmed by time-resolved phage titer assays. After introducing the sulfamethoxazole resistance gene sul2 into E. coli, the protection of the drug is completely abolished indicating that the on-target antifolate effect is driving the suppression of T4-induced collapse.
Our results identify a previously uncharacterized antagonistic interaction between sulfamethoxazole and T4, showing how this antibiotic can impact phage replication, even at subinhibitory concentrations. Ongoing experiments include a large genetic screen and dual-transcriptomics and quantitative proteomics to identify host factors underlying the molecular mechanism of this interaction.
Reference #3
Brochado AR et al (2018): Species-specific activity of antibacterial drug combinations. Nature // 10.1038/s41586-018-0278-9
Reference #2
Fungo G et al (2023): “Two Is Better Than One”: The Multifactorial Nature of Phage-Antibiotic Combinatorial Treatments Against ESKAPE-Induced Infections. PHAGE // 10.1089/phage.2023.0007
Reference #1
Theuretzbacher U et al (2020): The global preclinical antibacterial pipeline. Nat Rev Microbiol // 10.1038/s41579-019-0288-0
