Saturday, October 31, 2015

New Study Looking at the Viruses Colonizing Your Skin

Illustration of the complex microbial communities of
the skin. This includes viruses!
If you have been keeping up with previous posts, you have noticed that this has been a busy time on my end, and unfortunately blogging has had to take a back seat. I defended my doctoral thesis, earned my PhD, moved to a different University, and started a new position as a postdoctoral research fellow with Pat Schloss. Even though this has resulted in some busy weeks, these have been wonderful events and I am really fortunate to be going through this. Although these events are blog-worthy, I wanted to spend this week discussing one of our recent major publications about the skin virome.

Your skin is covered in microbes, including bacteria, fungi, and even viruses (see the illustration to the right)! We know viruses can directly impact your health by infecting your cells and causing diseases such as cutaneous warts and serious skin cancers like Merkel Cell Carcinoma. Viruses can also indirectly impact your health as bacteriophages that infect bacteria, modulate bacterial community compositions, and even promote pathogenicity like antibiotic resistance by transferring genes between bacteria. While we know a lot about how individual viruses impact your health, we don't know a whole lot about the health impacts of virus communities (the viromes). This unmet need for understanding viruses as members of their natural communities, instead of individual entities, is what motivated our recently published work.

Overview of our human subject sampling, processing,
and analysis.
We gained a lot of new insights into the viruses that colonize your skin, and published these findings in the open source journal mBio. Open source means anyone can access the paper, so go ahead and check it out! To summarize our work, we swabbed many different skin sites on each person within our healthy human cohort (see figure to the right). We developed methods to purify the viruses from the swabs, and then sequence their genomes. From here we used some sophisticated genomic analyses to characterize the healthy communities across skin sites, between people, and even over time.

The viruses on your skin are primarily bacteriophages, with the primary human virus being the Human Papillomavirus. These virus are quite different on different areas of your skin, and we quantified the relative community abundances of some clinically relevant viruses at different skin locations. Additionally, the viruses colonizing your skin are highly person-dependent, because your skin viruses are more similar to what they were a month ago compared to someone else right now.

As is illustrated in the figure below, bacteriophages can replicate in a lytic cycle (meaning they actively kill their host and replicate) or a temperate cycle (meaning they can exist silently in a bacterial host without killing it, just waiting for the right time to kill the host and replicate). Most of the viruses on the skin had markers suggesting temperate replication cycles, so they mostly hide silently in your skin bacteria. These types of viruses are able to promote transfer of antibiotic resistance genes through bacteria, and we found evidence for antibiotic resistance genes within the skin bacteriophages. Therefore, these skin viruses may be promoters of bacterial antibiotic resistance.

Overview of the general bacteriophage replication cycles. Phages can
be either lytic or temperate.

Now I don't want to hype this work, which happens way too much our field. This is an early study and is a stepping stone for future studies that will be able to offer even more insight into these skin viruses. While we offer some great insight into skin virus communities, and provide a strong foundation for future studies of skin viromes in disease, there are some important caveats and considerations. We outline these in the manuscript discussion, so I encourage you to check that out.

Finally, I have been so honored by the enthusiasm surrounding our work. The scientific community has taken notice of our work, and it has even been highlighted on Twitter. It is wonderful and encouraging to see people interested in what we are doing, and I look forward to publishing even more cool work that continues to impact the lives of others.

Think this work is cool? Have some questions, comments, or concerns about the paper or this post? Let me know in the comments below, or feel free to shoot me an email. I always love hearing from Prophage readers!

Works Cited

Hannigan, G., Meisel, J., Tyldsley, A., Zheng, Q., Hodkinson, B., SanMiguel, A., Minot, S., Bushman, F., & Grice, E. (2015). The Human Skin Double-Stranded DNA Virome: Topographical and Temporal Diversity, Genetic Enrichment, and Dynamic Associations with the Host Microbiome mBio, 6 (5) DOI: 10.1128/mBio.01578-15


  1. very cool and congratulations, truly interesting stuff.