ExtraCredit: Simon Lax seminar Category

Simon Lax’s presentation encompasses bacterial interactions within a normal household environment and how bacterial movement and interactions occur in a hospital setting. He retrieved his data from several houses and a hospital/clinic, and he discussed how microbes can leave microbial signatures along their surroundings and how they are more prevalent the longer the microbes are present in that certain environment.

As for the hospital setting, Simon Lax retrieved his data from various hospital rooms, hospital floors, door knobs, doors, patients, and etc. He then used this data to study and compare the microbiomes that were found. Simon Lax also made concrete graphs and tables that explained his data efficiently.

I really liked how detailed and organized Simon Lax’s presentation was, especially the data that he presented. What really peaked my interest was the concept of microbial signatures because its interesting how microbes interact with their surroundings. Also, I find it interesting that the longer a person stayed in their specific environment, the more similar the microbes are to each other.

The seminar’s major points pertained to how our built environment resembles its occupants and why this is important to study. Why should we care about this? One reason is that our microbiome and our surrounding microbiome play a big role in our health. The skin microbiome was the focus of Simon Lax’s research and he has found enormous diversity between people’s skin microbiome just on a day-to day basis. People’s built environment really does resemble what is on their skin. For instance, people’s feet and floor maintained relatively similar communities, but the bacterial communities found on people’s hands and therefore phones changed. With something changing so frequently (keeping in mind we shed millions of bacteria off of our skin onto a variety of surfaces that we touch), how does this affect health or help with forensics? These are questions he addresses.

I think overall it was a really fascinating seminar and provokes people to consider how interacting with the built environment impacts microbial diversity, human health, and how we approach forensics. It makes sense that the environments we interact with the most resemble much of the bacteria found on our skin, especially our phones, which change in their bacterial communities as our hands do.

I do wish he had been able to discuss the specific (or more specific) kind of bacteria found in the hospital setting though. As he mentioned (and as we have discussed in class), using 16S rRNA sequencing does not yield useful results in terms of identifying specific strains of bacteria or determining pathogenicity, which I feel in a hospital setting is important to determine. I did also wonder if antibiotic resistance genes increased over time in the hospital environment they studied, but he did address that this would take more time and research, seeing as the hospital they are studying has not been open for very long. I am also wondering if there is one factor related to the skin microbiome that contributes to an increase in antibiotic resistance more so than anything else in hospitals. Is it the staff skin microbiome, which has higher levels of microbial diversity, since they are interacting not only with the patients, but also with their environments? What are other ways the skin microbiome contributes to increased antibiotic resistance?

Summary: Simon Lax began his seminar by stating that our relation to our microbial sources are changing significantly due to the fact that we are becoming an indoor species. According to him, humans are spending about 90% of their lives indoors! This is causing such a change because indoor environments are created to limit the growth of microbial life. Simon told us about the Home Microbiome Study that was done in order to have a better understanding of the relationship between our own skin and microbes found in our indoor environments. This study seemed to have found certain microbes that could be almost used as a “fingerprint’ to help track the way in which humans transport microbes. This study led to a follow up study where Simon collected samples from personal belonging such as phones in order to see a relationship between the microbes observed. Lastly, was a study in a hospital to track the pathway of microbes from the beginning of the day to the end.

Reflection: I found this seminar to be pretty difficult to follow along with as it was pretty fast paced. However, I really enjoyed the concepts of the presentation. Since starting this Microbiology course, I have become more aware and curious about the microbes on and around me in my everyday life, so I find this topic to be extremely interesting. I would love to experience something similar to the hospital study because so many people come in and out of those doors and there must be such a diverse population of microbes. It would be so fascinating to see how microbes work their way from the doors and throughout the building.

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).

Summary:  In his presentation, Simon Lax provided background information to provide insight into he did for his research, such as information on 16s rRNA. The basis of his research examined the microbial communities in buildings, such as houses, and how those microbes resembled the people that inhabit those places. There seemed to be similarities between the microbes found on people and the microbes that were found in the houses that he sampled from, and looking into the role that people play in transporting microbes. Hospitals are another place that could show how microbes flourish because nurses are tending to patients that could be infected with bacteria or other types of microbes. Even though hospitals and other health care facilities are constantly cleaned and sterilized, that may encourage antibiotic resistance because the bacteria and other microbes are trying to find away to keep reproducing.

Reflections:  Although informing, Simon Lax presented his information in a really fast-paced manner which made it really hard to follow what he was explaining. The results were very in-depth and there was a lot to take in to comprehend. The main thing that made it hard for me to listen to his presentation was the fact that he talked so fast. I thought it was interesting how the results showed similarities among what microbes were found in the houses and on the people that lived in those houses. Also, it seemed as though the microbes that are found on our skin and in the place that we live in are influenced by the lifestyle that we live, whether we have pets or spend a lot of time outside. When he reached the portion of the presentation about the types of microbes in the hospital, it made sense that microbes can build up antibiotic resistance because they grow on surfaces that are constantly sterilized indicating that the bacteria and other microbes need to find a way to survive. These microbes survive by building up resistance to whatever the hospitals use to sterilize the surfaces. In class, we have learned that microbes grow where there are optimal conditions, meaning that they grow where the environment is best for them. If people are spending a lot of time in certain areas, the microbes inhabiting those places are going to travel with the person to potentially be introduced to other optimal environments. One question that popped in my mind while listening to Simon Lax’s presentation is: how would this study contribute to reducing the chance of getting a disease while in a hospital, or another “sterile” place? What could this study suggest about people’s lifestyles?

The seminar was an overview of the various research projects done by Simon Lax and colleagues in the field of metagenomics. His first study consisted of sampling several households and the people living in them for an extended period of time to analyze how the microbiome varied between location on the body, individuals, and households. He looked into the correlation between the microbes on the surfaces of the house and the people’s and animals’ coming into contact with them. Another study he mentioned followed him and one of his fellows, with samples collected from their shoes, cell phones and various surfaces they touched. The last project was centered around a hospital, starting before it opened and following the microbial diversity in two of its floor after patients and nurses started occupying  them.

It seems to me like the applications of microbial fingerprinting are not very useful in the forensic and medical field; the microbial community on surfaces disappears just a few days after an individual stops touching them, and in crowded places there’s just too many microbes to be able to isolate a specific track.

The connections to our class include the use of bioinformatics and DNA sequencing, and the idea of microbiome, which we have discussed before, both in relation to the lab project and to human health, especially the gut microbiome.

I thought it was very interesting to see that use of antibiotics does not affect the skin’s microbes, but I would like to know if it affects the gut’s. Also, as one of the people present at the lecture mentioned, how does genetic relatedness impact the microbiome? I wish we had spent more time talking about people moving in together. How do their microbes change, and how quickly? Is there selection for the most successful microbes between individuals?