Floor Six: Microbiome

Maurice waits pensively as his lover shakes dirty martinis in the kitchen. The vodka calms his mind, and stirs microbes in his stomach and intestines that influence his health. Those microbes may also mix with some bacteria covering her sofa, which are currently spreading to his shirt. She then delivers bad news: “I’m not leaving my boyfriend.” Maurice takes his hurt pride with him out the door, but he leaves behind thousands of microbes from his skin and guts.

Floor Five: Earth and Water

Polly washes away more than dirt and sweat. At every rumble in her roller derby match, she swaps skin microbes with her teammates. Some of these now float down the drain, but she’s being hit with millions more. A microbial flood wafts in through the window, and others pour down from the showerhead. Tap water in the United States contains hundreds of types of bacteria per liter. Luckily, none surveyed in a recent study were known pathogens.

Floor Four: Shedding

Len’s dog leaves white hairs all over his clothes and carpet. What Len doesn’t realize is that he sheds too. In a single hour, a person contributes 10 million microbes to the area around them, by sloughing microbes from their skin and re-suspending settled microbes as they walk. Many of the microbes on Len come from his dog, and studies suggest these microbes may shift his gut microbiome toward bacteria that protect him from allergies. Gary and Larry, the dudes downstairs, may get lucky when the pooch greets them, spreading microbes with every pounce and lick. “Who’s a good boy?”

Floor Three: Material

Newlyweds Elsa and Oliver splurge on home décor: organic cotton sofas, a mid-century oak table and a wool high-pile rug to suit their mature and modern sensibilities. As eager as they are to be on the next Dwell home tour, what they have yet to consider is that in choosing their wares they select different microbial communities. Microbes don’t just inhabit dirty surfaces; they live between the fibers of walls, on windowsills, and on natural and synthetic materials—all of which host distinct sets of microbes.

Floor Two: Climate

Gary, an environmentally conscious vegan, keeps his half of the floor cool, preferring to save energy. Larry, a glutton, turns up the heat. Neither realizes their differences reach far beyond lifestyle, and stretch to the microbes that surround them. Hot and dry rooms have been found to harbor lots of Staphylococcus epidermis, a common skin microbe, while cool rooms contain more Ralstonia pickettii, a bacteria that’s common in water, soil, and on plants. In other words, Gary’s microbes are tree-huggers too.

Floor One: Antimicrobials

Peter scrubs away the scent of Len’s dog, and then he scrubs a little more. He manages to destroy many of the microbes brought in by his neighbors at his housewarming party the night before. But was it necessary? Some bacteria, such as the one that causes fatal outbreaks of Legionnaires’ disease, deserve to die. But others killed in our war against microbes might be the ones keeping us healthy.