Your home is a garden of bacteria; you’ll be fine

Friday, January 31, 2020, Vol. 44, No. 5

Two weeks ago, I mentioned that Bob Harwood, a homebuilder with some 600 homes under his toolbelt, had recommended that anyone working in the residential real estate world should read the book “Never Home Alone.” In spite of his vast knowledge of construction, Harwood possesses an unquenchable thirst for knowledge.

As fate would have it, Nashville’s treasured Parnassus Books had the book in stock and, after perusing it, there is no doubt Harwood is correct in his assessment. Many of the observations seem obvious, but the research is intense. The book was written by Rob Dunn, a scientist by trade who knows how to spin a web.

Dunn’s hero is Antony van Leeuwenhoek, which is not exactly a household name. Nor are any of the 200,000 organisms living within our walls. Van Leeuwenhoek, forevermore known as Antony in this column, lived in Delft, Holland, and conducted most of his studies there. It was in 1676 that he began to learn about the organisms inhabiting houses.

While attempting to crack a peppercorn and learn what made pepper spicy, he began to discover thousands of species of bacteria in houses. Antony’s studies led Dunn and others to learn that “more species of bacteria have been found in homes than there are species of birds and mammals on Earth.”

Studies now show, Dunn says, that children growing up today spend about 93% of their time in controlled environments such as cars and buildings. Manhattan, for example, has 172 square kilometers of residential living space and only 59 square kilometers of land area.

With more people spending more time inside and scientists discovering more bacteria, it was soon learned that some bacteria is bad and can cause illness, even death. Understandably, the scientific community began to create ways to kill bacteria.

Unfortunately, while killing the bad bacteria, the sterilization often eliminated good species that held the bad creatures in check.

These pesticides and antimicrobials unknowingly assisted resistant species such as German cockroaches, bedbugs and MRSA bacteria. Dunn has concluded that the evolution of the species within our homes is “arguably the fastest occurring (evolution) anywhere on Earth.” He also notes that the indoors is the fastest growing biome on the planet.

In 1676, when Antony worked his way through his pepper water, the breeding ground for his species, he identified an organism that were 1 millionth the volume of a grain of sand. We now this as bacteria; van Leeuwenhoek and his group were not aware of bacteria at that time.

Louis Pasteur was credited with discovering that pathogens cause disease, but Antony Leeuwenhoek thought most of the animals he was seeing under the microscope were harmless. He was right, as Dunn asserts; of all the bacterial species in the world, only 50 regularly cause disease.

In studying Iceland’s hot springs and the geysers that go along with them, Dunn discovered certain species only live where there is hot water. Voila! Now the obvious begins to permeate the studies. The water heater in most houses has water as hot as the hot springs, the freezer has temperatures that rival the coldest tundra and the stove creates an environment hotter than the hottest desert.

Naturally, bacterial species that live in frigid temperatures would make their way into freezers and warm, wet seeking species would reside in water heaters, while desert bacteria gather at the stove. These species moved in unnoticed as the appliances around the houses changed.

One of Dunn’s most interesting discoveries is that some of the bacterial species found in homes were bodily bacteria, and most of the species were not pathogens, bacteria that can cause disease, but detritivores. In short, our bodies are falling apart even when we are alive, leaving a cloud of us everywhere we go.

Humans are falling apart at a rate of 50 million flakes a day, and each flake has thousands of bacteria living and feeding on it.

“Riding their skin flake parachutes,” Dunn writes, “these bacteria fall from us like a steady snow.” The process of flaking is called desquamation. If you are feeling a bit tired, you probably over-desquamated that day. My assumption, not that of Dunn or the Dutchman.

The faint of heart may want to skip this paragraph. Dunn has learned that the drains found in sinks contain a mix of species that is seen nowhere else and contains bacteria and tiny drain flies whose larvae feed on drain bacteria.

The secondary offender is the showerhead. They get dry, then wet, then dry again and are covered in films of unusual microbes. These microbes are typically seen in swamps. Dunn has determined the development of the biofilm that forms on the showerhead.

“Biofilm is made by individuals of one or more species working together to achieve the common goal of protecting themselves from hostile conditions (including the flow of water that threatens to wash them away). The bacteria make the infrastructure of the biofilm out of their own excretion.”

It gets worse. “In essence by working together, the bacteria poop a little indestructible condominium in your pipes, a condominium built of hard-to break- down complex carbohydrates,” he says.

There is an answer and that is to make the house a garden of bacteria – good and bad – and other microbes and antipathogens. Wash your hands regularly and change the showerhead and the drain.

Richard Courtney is a licensed real estate broker with Fridrich and Clark Realty and can be reached at