A microfabricated device defining a high density array of microwells is described for cultivating cells from a sample. A series of unique tags may be disposed in the microwells to identify one or more species of cells and locate the particular microwells in which each species was cultivated. A unique tag may be a nucleic acid molecule including a target-specific nucleotide sequence for annealing to a target nucleic acid fragment and a location-specific nucleotide sequence predetermined to identify one or more microwells. The device may be incubated to grow a plurality of cells, which may be split into an analysis portion and a reserve portion. High throughput methods are described for cultivating, screening, and determining a relative and/or absolute abundance of cells from a sample.