Another interesting study that makes you think about our microbiome. From NPR:
Stinky T-Shirt? Bacteria Love Polyester In A Special Way
Anyone with a drawerful of T-shirts knows that the synthetic ones can get sour after just a brief jog, while old-school cotton T-shirts remain relatively stink-free all day. And now science explains why. The bacteria that flourish on a sweaty polyester T-shirt are different from those that grow on cotton, researchers at the University of Ghent in Belgium found. Polyester makes a happy home for Micrococcus bacteria, while Staphylococcus, a common armpit denizen, was found on both poly and cotton.
Microbes love the cozy warmth of the human armpit; it's like a trip to the tropics without ever having to leave home. And it's crowded in there. Those microbes eat compounds in sweat and generate odors, which support a flourishing deodorant industry.
The scientists asked 26 volunteers to take a spinning class while wearing shirts made of cotton, poly or blends. The shirts were then incubated for a day, and the microbes extracted and DNA fingerprinted. Volunteers also had their armpits swabbed.
It turns out the bugs on the shirts are different from the bugs in the pits. While Corynebacterium is thought to be the main cause of armpit body odor, there was no Corynebacterium on the clothes. Instead, Staphylococcus flourished on cotton and poly, and Micrococcus, bacteria also known for making malodor, loved polyester.
He's also trying to help people with excessive body odor by giving them armpit bacteria transplants. "We have done transplants with about 15 people, and most of them have been successful," Callewaert, a Ph.D. student in applied biological sciences at the University of Ghent, tells Shots. "All have had an effect short term, but the bad odor comes back after a few months for some people."
Manufacturers have tried to make polyester fabric less hospitable to bacteria by impregnating it with antimicrobials like silver nanoparticles or triclosan. Both products have been criticized as having potentially negative impacts on the environment, and there are few data on how they might affect the wearer. Callewaert thinks the ultimate solution will be something more organic — supplant bad bugs with good ones.