Better get out of bed!

Don’t put your head down in here!

From, and reporting on an article in Discover magazine: “Your pillow is a lot like a toilet seat, microbially speaking.” And it’s not an exaggeration! Students in BIO230 should be well aware of the microorganisms that are inside us and surround us. It is estimated that the number of prokaryotic cells occupying the volume of the human body outnumber the human cells in that volume by at least ten-fold. Fortunately, human cells are significantly larger than prokaryotes, so we still outnumber our microbial flora by mass, if not in number. Outside the human body, we interact with huge numbers of microorganisms with every breath. DNA analysis indicates that there are upwards of 10 million bacteria in every cubic meter of air. Those bacteria would enter the lungs through just a few minutes of breathing.

The authors of the article in Discover point out that perhaps contrary to popular perception, the movement of humans into our houses does not mean that we now live in a more germ free environment. Every surface we interact with is teeming with microbes that vary hugely in their pathogenic, or disease causing, potential. Complicating analysis of indoor microbes is the fact that we actively move air throughout our buildings, and this moves micro organisms.

Norm Pace of the University of Colorado has been a leader in the analysis of microbial ecology, and has described the vast number of organisms that inhabit things like shower heads. In addition to getting your body clean, you are also aerosolizing microbes and inhaling them when you breath. In clinical settings, reservoirs such as shower heads can be sources for nosocomial infections, which can lead to very poor patient outcomes.

Jessica Green and her collaborators at the University of Oregon’s Biology and the Built Environment Center (BioBE) argue that we must come to terms with these organisms, particularly in the hospital environment. They suggest that if the hospital ecosystem promotes the growth of dangerous microorganisms, we should endeavor to find a way to create a healthier microbial ecosystem, by altering floor plans, reconfiguring the ventilation system, and actively moving more healthful bacteria from outside to inside the building. They have found that buildings have created microenvironments, where distinct locations have very defined populations of bacteria. The organisms on your pillow for instance are far different than the ones on the floor by your bed. By understanding how these two populations interact and contribute both positively and negatively to our health, we can make more informed decisions about how nosocomial infections might be curtailed!


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on October 22, 2012, in gross, Strange but True. Bookmark the permalink. 2 Comments.

  1. I would like to elaborate below the ventilation system and the shower heads, and talk about the floor. It always baffled me why some of the nursing homes I was employed at had carpet on the floors rather then some sort of linoleum. I understand from the interior designer’s viewpoint the carpeting looks nicer until it starts getting wet from various fluids, use your imagination, of course. Which leads me to my point. Underneath the carpeting the floor never really dries and thus mold and bacteria have a wonderful medium on which to grow. In fact at my past job when they did finally switch out the carpeting the smell that filled the halls as the carpet was pulled up was at times unbearable, and also supports the reason my work shoes are not allowed to walk into my apartment!!!!

    • Right! My in-laws used to have carpeting in the bathroom, which always was gross to me. When my kids were really young, they used to seriously douse the bathroom floor at Grandma’s house, and I imagine that the subflooring is still wet a decade and a half later. Fortunately, it has been replaced with linoleum, so at least the mold is sealed beneath that barrier! Of course, the opposite trend in health care settings today is to surround ourselves with antimicrobial surfaces, and that leads to all sorts of other issues such as antimicrobial resistance.

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