{
  "id": 10116085,
  "title": "Loss of restriction-modification methyltransferases drives persistence to fluoroquinolones in Pseudomonas aeruginosa",
  "url": "https://urgent.news/2026/09/26/loss-of-restriction-modification-methyltransferases-drives",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-26T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.26.754597v1?rss=1"
  },
  "original_language": "en",
  "account": "Recent interest in phage therapy has reignited research into the relationship between phage resistance and antibiotic susceptibility, leading to the exploration of non-canonical cellular functions by defense systems. However, it remains unclear if intracellular antiphage defense systems impact bacterial physiology, resistance, or persistence to antibiotics.\n\nIn this study, researchers found that the type I restriction modification (RM) system, which typically functions to protect bacteria from phages, also significantly influences the physiology of the opportunistic pathogen Pseudomonas aeruginosa. Deleting the type I RM methyltransferase HsdM leads to a smaller bacterial nucleoid, delayed DNA replication initiation, and a longer lag phase in P. aeruginosa PAO1.\n\nMoreover, CF patients' P. aeruginosa strains lacking the RM type I system exhibit slower growth compared to those isolated from other infection sites and encoding this system. Deleting HsdM selectively increases the levels of persisters that survive fluoroquinolone treatment, displaying an enhanced SOS response without acquiring resistance. Crucially, researchers measured increased persistence to fluoroquinolones in CF isolates lacking the type I RM system, establishing a functional link between RM systems, slow growth, and persistence to fluoroquinolones.\n\nThese findings suggest that antiphage defense systems could play a new and significant role in understanding bacterial susceptibility to antibiotics, placing these systems at the forefront of the field.",
  "summary": "The resurgence of phage therapy has renewed interest in the interplay between phage resistance and antibiotic susceptibility and has stimulated research in the emergent field of non-canonical cellular functions carried out by defence systems. Yet it remains largely unknown whether intracellular antiphage defence systems influence bacterial physiology, resistance or persistence to antibiotics.…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}