Beyond predation: potential metabolic roles of intracellular bacteria in Acanthamoeba ecology

Although Acanthamoeba is well known as a reservoir and ‘Trojan horse’ for other microbes, its relationship with intracellular organisms may extend beyond protection. Here, we discuss that certain bacteria contribute metabolically to the host, breaking down complex substrates and providing nutrients that expand its ecological adaptability. The proposed model reframes amoebae not only as predators and shelters but also as metabolic consortia, with implications for environmental microbiology, protist ecology, and the evolution of opportunistic pathogens. Further studies using integrated multi-omics and co-culture approaches, combining metagenomic and metabolomic profiling of Acanthamoeba-bacteria interactions and transcriptomic analyses will help identify bidirectional metabolic exchange and functional gene expression within the symbiosis.