This mid-summer human microbiome journal club was small but mighty, with representatives from 3 laboratories, undergraduates to post-doctoral fellows.
On Friday, Saad (future MD-PhD in the Surette lab) led us through a discussion of Universality of Human Microbial Dynamics, Bashan et al. We will admit that it took us a bit of effort to fully understand the author’s definitions of overlap and dissimilarity. However, after a few memorable quotes (“It’s pretty much like… I don’t know”; “…and then you take the square root of that for some f$#%ing reason”) and some pacing of the meeting room, the attendees worked together to truly understand the dissimilarity-overlap curve (DOC) method.
And I’m sure glad we did- because this method appears to be powerful. The first 2 figures of this paper are used to outline DOC and show that the application of this method to real and raw data indicates that there are universal underlying dynamics present within human-associated microbial communities. The authors then apply their method in two ways. First, they use Human Microbiome and Student Microbiome Project data to show that this universality holds in communities associated with the gastrointestinal tract and mouth but that there are less evident in communities of the skin.
Perhaps what the group found most interesting were the results of the last Figure. In Figure 4, the authors used their DOC measure to show a lack of universal dynamics in individuals with recurrent Clostridium difficile infection, citing their disrupted microbiomes as the culprit. However, after these individuals underwent Feacal Microbiota Transplantation, the DOC analysis produced a strong negative slope, suggesting universal dynamics.
This paper displayed a really interesting application of ecological methods and theories to microbiome research. We are excited to see the application of this method in future studying of microbial communities.