At left,a clump of Staphylococcus epidermidis bacteria in the extracellular matrix, which connects cells and tissue. At right,the bacterium, Enterococcus faecalis, which lives in the human gut, a microbe that will be studied as part of NIH’s Human Microbiome Project.

First published in the August 17, 2012, 2:21 p.m. edition

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