{
  "id": 3181307,
  "title": "Pre-existing antibiotic tolerance facilitates plasmid-mediated carbapenem resistance evolution in clinical Klebsiella pneumoniae",
  "url": "https://urgent.news/2026/08/24/pre-existing-antibiotic-tolerance-facilitates-plasmid-mediated",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-08-24T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.24.746623v1?rss=1"
  },
  "original_language": "en",
  "account": "A long-term study examining more than 800 clinical Klebsiella pneumoniae isolates from 1997 to 2020 has revealed a key mechanism behind the evolution of carbapenem resistance in these bacteria. Among the isolates, 17.6% displayed hidden ertapenem tolerance, a phenomenon where bacteria survive exposure to 30 times their specific ertapenem MIC. This tolerance was mostly undetected and did not delay bacterial growth, yet it was more common in ertapenem-resistant strains. The presence of tolerance was noted even before the introduction of local ertapenem use and was more prevalent in strains with carbapenem resistance. Crucially, tolerant bacteria with pre-existing resistance plasmids were better able to acquire resistance plasmids, survive antibiotic exposure, and had an accelerated evolution of resistance to ceftazidime-avibactam. Genetic analysis identified the uhpABC regulatory operon as a potential candidate linked to tolerance, and its coordinated expression enhanced ertapenem survival. In summary, the findings suggest that antibiotic tolerance, a hidden phenotype, can play a significant role in the evolution of carbapenem resistance in K. pneumoniae, highlighting the importance of understanding pre-existing bacterial characteristics in the context of antibiotic use and resistance evolution.",
  "summary": "Antibiotic tolerance enables bacteria to survive bactericidal antibiotic exposure and has been linked to resistance evolution in laboratory systems and individual infections, but its role in plasmid-mediated resistance evolution in clinical populations remains unclear. Here, we analyzed a longitudinal collection of more than 800 clinical Klebsiella pneumoniae isolates spanning 1997-2020. Among…",
  "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."
}