{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T15:00:48Z","timestamp":1790089248125,"version":"4.0.1"},"reference-count":49,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>\n                    Antimicrobial resistance (AMR) is a global public health crisis driven not only by clinical antibiotic misuse but also by environmental reservoirs that remain insufficiently characterized. Free-living amoebae of the genus\n                    <jats:italic>Acanthamoeba<\/jats:italic>\n                    are ubiquitous eukaryotic protists that graze on diverse bacterial communities via phagocytosis, yet certain clinically important pathogens\u2014including\n                    <jats:italic>Legionella pneumophila<\/jats:italic>\n                    ,\n                    <jats:italic>Mycobacterium<\/jats:italic>\n                    spp. and\n                    <jats:italic>Pseudomonas aeruginosa<\/jats:italic>\n                    \u2014have evolved sophisticated mechanisms to survive and replicate within the amoebal phagosome. This intracellular niche serves simultaneously as an evolutionary training ground for bacterial virulence and immune evasion, a physical shelter against environmental biocides, and a hotspot for horizontal gene transfer (HGT) of resistance determinants. Strikingly, the molecular strategies used to subvert amoebal killing are mechanistically conserved with those deployed against human macrophages, effectively shielding amoeba-trained bacteria from both innate and adaptive immune clearance. Recent studies demonstrate that\n                    <jats:italic>Acanthamoeba<\/jats:italic>\n                    -associated bacteria exhibit significantly elevated multidrug resistance indices compared with free-living counterparts, that plasmid-borne carbapenem-resistance genes can transfer between co-ingested species within the phagosome, and that the highly resistant cyst stage shields intracellular bacteria from chlorine disinfection at concentrations exceeding water-treatment standards. This review provides a comprehensive synthesis of the molecular and immunological mechanisms underlying intracellular bacterial survival within\n                    <jats:italic>Acanthamoeba<\/jats:italic>\n                    , evaluates the evidence for AMR amplification through protist\u2013bacteria interactions, and frames these processes within the One Health paradigm connecting environmental reservoirs to clinical and veterinary outcomes.\n                  <\/jats:p>","DOI":"10.3389\/fimmu.2026.1874010","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T14:00:49Z","timestamp":1790085649000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Acanthamoeba as a microbial Trojan horse: intracellular endosymbionts, adaptive immune evasion and antimicrobial resistance dissemination from a one health 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