What bacteria live in the gym?

A lot of research goes into understanding the complexity and dynamics of the human microbiome in the GI tract or the mouth, to name a few locations. In an article published by Microbiome, researchers at Northwestern University took a different perspective in that they looked at how the human microbiome affects the environments around us. A very interesting point raised by the article is that Americans spend most of their time in so-called “built environments,” which are indoors. The microbes of these indoor environments are mainly affected by the humans that interact with them, so the scientists at Northwestern University took to studying how the bacterial composition of indoor athletic equipment and facilities are affected. This specific environment was chosen mainly because of the numerous different human encounters it experiences.

For 2 days, the researchers collected swab samples in 3 athletic facilities. Samples were collected every 2 hours from the floor, mats, elliptical handles, free weights, and benches from 8 am to 6 pm, and a total of 356 samples were collected.  After sequencing and analysis, the researchers concluded that, consistent with all three facilities, the bacteria found on the equipment was most likely to be from the human skin, with Pseudomonas and Acinetobacter showing up in the most samples. Besides microbiota from the skin, other bacteria were found to be abundant such as Bacteroides from the human intestinal tract on elliptical handles and Finegoldia, also from the GI tract, on benches.

As for which sampled location had the most stable bacterial community, it was found that the floor and mats showed the least change in structure. This is most likely because elliptical handles, free weights, and benches come in more direct contact with human skin. Across the board, the only genera which were found in all samples from every surface type were Staphylococcus and Pseudomonas. It is important to remember that none of this means athletic facilities are blooming with harmful bacteria, and we should stay far away. In fact, the environment is not very conducive to the thriving of bacteria, because it lacks a lot of resources. What we should take away from this study is that any surface that comes in contact with human skin is likely to reflect the microbiome of that person.