Feeding Caenorhabditis elegans E. coli engineered to express human HSP90 extended both lifespan and healthspan without costing fertility. The authors propose the exogenous chaperone acts as an extracellular signaling ligand, engaging kinase networks that activate three longevity transcription factors: DAF-16, SKN-1 and HSF-1. Pairing dietary HSP90 with the HSP90 inhibitor tanespimycin produced additive lifespan gains, and a probiotic E. coli Nissle 1917 strain constitutively expressing HSP90 also lengthened worm life. The evidence comes entirely from roundworms, not humans. The paradox deserves attention: HSP90 inhibitors extend lifespan across species, yet supplying more HSP90 helps too, hinting that intracellular and extracellular HSP90 play opposing roles. The ligand mechanism is inferred, not proven, and worm lifespan results frequently fail to translate to mammals; bacterial food source effects are a known confounder in C. elegans work. Nothing here supports taking HSP90 supplements. A protein delivered orally would face digestion in mammals, and extracellular HSP90 is already linked to inflammation and tumor-promoting signaling in mammalian biology, a cautionary note. The engineered probiotic is a creative delivery concept, but it is far from any human application. This is a bioRxiv preprint that has not yet been peer reviewed, so findings may change. Overall, the work is a novel but early, hypothesis-generating step, incremental for aging biology and irrelevant to personal health choices today.