Extra Credit: Simon Lax

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.

Extra Credit: Simon Lax

Simon’s seminar was primarily concerned with analyzing our personal relationship that we share with the microbes present in our surrounding environment. As he states very early on in his presentation, the microorganisms in which encounter in our day-to-day lives greatly shape our own microbiome and our immunological health. Our microbiome and our relation to our microbial sources is significantly changing as we become an “indoor species.’ It is estimated that the human species spend about 90% of their time indoors. As Lax states, this change is resulting because these particular “built’ environments are simulated to limit the amount of microbial growth.

His personal research regarding this field of study consisted of various sample collections from different sources throughout candidates’ households. 16S RNA sequences  were targeted to analyze the resemblance of the human micrbiome with their innate surroundings. The results of his research indicate that the surfaces in these test subjects’ homes strongly resembled the microbiome of the individual. For example, he discovered that the floors of the home in which they reside.

Despite the fact that I had a little difficulty following this lecture, I found that the concepts he touched on were rather fascinating. I was very interested in his remarks concern an individual’s “microbial signature.’ It was really interesting for me to consider how an individual’s microbiome is subject to change once they leave their built environment. I feel that this research that he has conducted thus far has been rather supplemental to the field of microbiology, by allowing us to consider how our environment impacts of individual microbiome. It also reiterates the importance of microorganisms to the human body and the important role they possess in our daily lives.

Extra Credit Simon Lax Seminar

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?

Extra Credit: Simon Lax

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 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).

ExtraCredit Simon Lax

The overall idea Simon Lax presents in this seminar is that microbes are transferred from skin  to surfaces constantly. Recently, people mostly live indoors and try to remove all microbes from the indoor environment. The various studies he presents use the 16S method of identifying bacteria which we have learned about in lab. There were several recurring themes throughout his presentation. First, skin microbial signatures differ between people. This makes it possible to track the transfer of bacterial cells from skin to surfaces such as countertops, phones, floors and keyboards. A study in which people took samples from surfaces in their home and from their skin showed a strong correlation between the abundance of bacteria in a household and on the occupants’ skin. In his hospital study, Lax examined the transfer of microbes from patient and nurses skin to surfaces in the hospital, much like the study of occupants in their homes. The main issue he addresses is: How does the microbial community of a hospital change after opening and use of the facilities? He found that the pre-opening microbes came mostly from building materials and were environmentally acquired. Many things were found from this study but the most shocking is that the surfaces in the room and the patient’s skin began to have very similar microbial diversity, the longer the patient stayed there. Also, antibiotic resistant bacteria were most commonly found on frequently sanitized surfaces.

Though the conclusions about bacterial transfer presented in this seminar could have been easily predicted, it is important that someone has published peer reviewed evidence to support these ideas. We have discussed the transfer of infectious diseases in class in the form of the plague. It used to be impossible to track the transfer of bacteria before we had microscopes. Even with microscopes, there was no way to be certain it was the same type of bacteria until DNA sequencing became a commonly used tool in research. A question that popped into my head when watching this seminar was: Since antibiotic resistant strains of bacteria were most commonly found on frequently sanitized surfaces, should the use of sanitizers in a hospital setting be examined more closely?

Simon Lax Extra Credit

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?


Extra Credit – Simon Lax Lecture

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?


Extra Credit: Simon Lax

Simon Lax’s seminar was about microbiomes and the possibility of affiliating certain microbes to a specific person, like a fingerprint. Lax’s research on the importance of this “microbe fingerprint” came from both a forensic and health perspective. In a forensics type study, by comparing samples from someone’s shoe and the floor, Lax could essentially get an idea of who walked where. In a health study, Lax was able to see how microbes colonized in a hospital setting. Essentially, he could see how microbes in a room became more similar to the occupant over time. Further, he did a test of skin microbiomes and their relation to the patient’s diagnosis.

Our microbiology course made it clear to me that microbes are everywhere and essentially rule the world. However, I was unaware that microbes could be specific to a type of person and their environment. I always assumed microbes were random but it now makes sense that their being has some kind of order. This seminar related specifically to the lecture about viruses, specifically Norovirus, and how it is common on cruise ships. It makes sense such a segregated place such as a cruise ship would be prone to such outbreaks. A cruise ship is similar to one’s home which, as Lax pointed out, is a place where eventually everyone and most surfaces come to have similar microbes.

“Extra Credit Simon Lax”


The seminar was about the microbial interactions taking place indoors as opposed to a more widely studied interactions taking place outside.  Though the seminar was fast-paced and a little above my pay-grade (of knowledge, I mean), I was able to discern two main aspects of his study.  The first part of his study was the one in which he sampled from 7 different homes across the US.  They varied not only in location and occupancy number, but also whether or not pets were included.  He expanded his “microbial fingerprint” study to include his own interactions with his cellphone.  The second part of his study was the the one where he looked at how microbes colonize and move about in the hospital environment.  He did this as there is a growing concern for hospital-aquired illnesses such as MRSA.

The one particular thing I found most interesting about the seminar is the forensics aspect of the first part of his study.  I think it’s fascinating to consider that we as individuals might have our own unique microbial signature or at least be able to distinguish between individuals based on that signature.  I have no critical comments about his material (what I could follow, being rather newly exposed  with the vastness that is microbiology). We have spoken briefly about anti-biotic resistant microbes in class, and it was interesting to hear him note at the end about a possible future study of antibiotic resistance in microbes located in hospitals.  One question I would have is if it is feasible that sometime in the near future that microbial “fingerprints” would be used in real world applications such as crime scene analysis and processing.