Analysis of the interaction between the human skin microbiome and its environmental surroundings
Factors influencing the composition of communities are of fundamental importance in ecology. We report on changes in microbial communities as a result of interactions between humans and their environment. The microbial community found on the human skin is constantly interacting with external microbial communities. Although some studies examine diversity of the skin microbiome and some of the diseases that are associated with an altered skin microbiome, there is little research on how simple, every day interactions affect microbial communities. This research examined the interaction between the human skin microbiome and the microbial surrounding, specifically the interplay of microbial diversity between skin microbiota and tables in a biological laboratory. Surface samples (n=10) were collected from lab tables and volunteer’s forearms (n=31) before and after a three-hour lab class in accordance with IRB approved protocols. Samples were analyzed for changes in microbial communities by measuring (1) numeric differences in microbial diversity using culture based methods, (2) changes in microbial diversity determined by Randomly Amplified Polymorphic DNA (RAPD) finger-printing, and (3) changes in functional diversity using Ecolog plates.
No significant results were identified for numeric differences (CFU/ml) in microbial samples taken from people before and after lab or from tables before and after lab (p=0.706, p=0.468 respectively). On average, 21.9 ± 17.6 CFU/ml were present on forearms prior to lab and 23.7 ± 18.1 CFU/ml after lab. When comparing all table samples to all skin samples, skin samples had significantly greater CFUs/ml than table smaples (p<0.001). Changes in functional diversity were determined based on colorimetric changes in the Ecolog plates, and DNA fingerprinting was used to identify changes in microbial composition. Ecolog and DNA samples were analyzed using SPSS Hierarchical Clustering, which both showed table communities and forearms form unique clusters indicating both functional and compositional differences. These results also suggested changes occur in response to interactions between people and tables. Thus interactions over a short period of time (<3hrs) can significantly alter microbial diversity and function within the community.