Simon Lax Extra Credit

Simon Lax-Human Microbiome

Kirsten Veech

     This seminar addressed a very interesting topic, Simon Lax studies culture independent microbiology which is where he collects samples from environments sequences and targets 16S markers which determine a large part of diversity in microbes. These studies don’t look at microbes that are grown in labs. Lax’s research was focused on the human microbiome and how a persons microbiome is changed depending on their skin condition, environment and surroundings, and pets. The main questions that Lax was pursuing are; How much did home surface microbes resemble their occupants microbes? How unique microbe communities in individual homes are? What are there major interactions between people and their environment? and How stable are these microbe communities?

     These questions were answered by Lax conducting a study on 7 families who took samples from their skin, home surfaces, and pets every 1-2 days from 4-6 weeks. Lax found that surfaces in home do resemble their occupants quite a bit, more specifically he found that the occupants feet resembled the floors of the house while the occupants hands more closely resembled the counter and doorknob surfaces. This finding makes sense considering the transfer of microbes from hands to doors and feet to floors. By using beta diversity he also found that there was not a unique environment in different homes, there was a well mixed environment in each home. He found that there was a larger variety in homes with multiple occupants and pets vs a single occupant home. So to be clear the microbes found in homes were similar across the board. Stability of microbe communities was determined by comparing surface samples from day to day. Lax found that peoples hands had a low stability possibly due to the large amount of interaction with different environments through out the day while the floors had high stability.

     A really interesting point that Lax brought to our attention was that when a person leaves the home environment for a little while their “microbial signature” as he called it, will go away. This makes sense because that person is not coming in contact with these surfaces and keeping their microbial signature present, however I would have thought that their microbes that they brought to the house would have stayed present because they were in environments that they could live in so what would cause them to leave that environment if they have already successfully habituated there? This really shows what we learned in class that microbes are everywhere, and its super interesting that they are, in a way organized in their location around us. Its so cool to think that a single celled organism can be “organized” (using this term loosely because they don’t organize themselves, but certain microbes are more common in certain places).