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?

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