Using City Sewage to Survey a City's Microbiome

The team gathered samples over the course of a year from sewage treatment plants in 71 different cities in 31 states, chosen for their geographic spread and range of obesity rates. The leanest city sampled was Steamboat Springs, Colorado, with an obesity rate of 13.5 percent, while the heaviest was St. Joseph, Missouri, with a rate of 37.4 percent. Bacteria from human waste make up just a small proportion of the bacteria found in sewage. But using DNA sequencing, the researchers could identi...