FILE — Petri dishes with fecal bacteria colonies, which are used to produce a final product, at Vedanta Biosciences, in Cambridge, Mass., Feb. 5, 2019. Two patients contracted severe infections, and one of them died, from fecal transplants that contained drug-resistant bacteria, the Food and Drug Administration reported on June 13, 2019. (Kayana Szymczak/The New York Times) XNYT215 XNYT215