Winston Churchill said. “We shape our buildings, and afterwards our buildings shape us.”
While all building owners strive to comply with federal and local building codes, perhaps hospital CEOs and facility managers have the safety of the built environment foremost in their minds. Patients, especially vulnerable due to the condition that caused their admission, have been suffering from injuries related to the hospital in alarmingly high numbers. In particular, high numbers of inpatients acquire healthcare-associated infections (HAIs). These are new infections that are a consequence of the patient being in contact with the hospital building, caregivers, and invasive procedures that direct their own organisms into the wrong places. Hospitals now have robust Infection Control departments and policies in an attempt to eradicate all new micro-organisms that might come into contact with patients. While this approach certainly makes sense in many ways, recent research on human microbes and their relationship to buildings may change the way we think about building hygiene.
The microorganisms in and on patient and staff bodies populate the hospital building and ultimately contribute to patient outcome.
We live with tiny roommates
Humans rapidly colonize indoor spaces, leaving viruses, bacteria, and other microbes from our skin on surfaces and in the air. An average person emits a plume of about 37 million bacteria per minute that disperse throughout a building and can survive for extended periods.
Research on the micro-ecology of hospitals show that patient rooms quickly acquire the patient’s unique microbial signature. These predictable patterns of bacterial growth have been studied more closely in non-healthcare environments, yielding fascinating results. A person could go on a indoor microbial safari in their own kitchen. The micro-ecology of areas near appliances resembles exotic lands with extreme climates. The moist area above the faucet harbors organisms found in rain forests, the dry and hot stove exhaust vent provides respite for temperature resistant spores found in desserts and in volcanoes, and dark cupboards grow unique bacterial communities found in low sunlight countries.
Clean, clean, clean! But – is bug free even possible, or necessarily good?
We hope that most of the micro-organisms in buildings are relatively benign. Whether benign or not, eradicating them is not possible and may not necessarily be desirable. A new strategy of managing healthcare buildings may be to control the extreme micro-environments associated with mechanical systems and interstitial spaces rather than to strive for total indoor sterility. In fact, the use of powerful disinfectants has created unbalanced micro-environments that we know little about. Removing pathogens that might be harmful has undoubtedly saved lives, however, we have also fostered unbalanced microbial species and communities that may be more harmful and resistant to disinfection.
Research has also shown that people exposed to a wide diversity of microbes are healthier than those exposed to narrow ranges of bugs. In this way, some microbes living in our buildings can affect our health in a positive way. Recent studies have revealed some very interesting associations between building micro-flora and human health.
- Increased fungal diversity indoors has been linked to reduced rates of asthma.
- A study published in 2012 found that hospital patients were more likely to encounter harmful pathogens when their rooms were mechanically ventilated compared to rooms with access to fresh outdoor air.
- Studies show that children living with indoor dogs, known to have a wide diversity of bacteria, have fewer ear infections requiring antibiotic treatment.
If building conditions influence the communities of indoor micro-organisms, what building design and maintenance is best for creating a healthy micro-ecology to protect patients? Microbes from humans, outdoor soil and air enter buildings via ventilation systems, water, carpets and other materials. How do building conditions such as humidity and air temperature influence indoor microhabitats and consequently, the composition of indoor bacterial communities? As we learn more about indoor micro-ecology; architects, engineers and building information systems can manage room designs and materials, ventilation system operating parameters and maintenance policies that affect the ecology of microbes within a space. With this understanding, building management systems can foster healthy indoor biodiversity within healthcare facilities, as well as balance operating costs and energy efficiency.
In summary, there is significant evidence that the microbes living in and on people play a critical role in human health and well-being. In turn, these organisms rapidly populate our buildings and create complex ecosystems. Architectural design and building management can modify the indoor micro-ecology, ultimately influencing the human microbiome and human health.
8 years ago
This is an excellent article and compliments the work done a few years back by Prof Jessica Green at U of Oregon. In that work Prof Green highlights from her research how the microbiome of mechanically ventilated buildings is much less diverse and had a higher concentration of pathogen bacteria than the microbiome of the human body and / or the landscaped exterior of a building (the building used in this research is a Platinum LEED facility on the U of Oregon campus).
Establishing a more natural balance (ie: one resembling that of the landscaped exterior of the building, which had the most diverse microbiome with the lowest concentration of pathogens) in the interior of mechanically ventilated buildings should be the core objective.
However we spend way too much time, effort and money at trying to “kill” every bacteria, (the good which we need, as well as the bad), to create a totally un-natural and unsustainable indoor environment.
The conventional combinations of Physics (sweeping, wiping, vacuuming et al) and Chemistry (bleaches, quats, oxidizers et al) fail to remove the biofilm that is present on virtually every surface. Given pathogen biofilms can replicate as quickly as every 20 minutes, its not long before the problem of harmful, pathogen bacteria has returned. Biofilms also provide protection to these pathogens by preventing the conventional disinfectants and sanitizers penetration the pathogens’ cell walls. (The CDC and NIH have noted that biofilms make pathogens between 500 times and 1,000 times more resistant to the conventional sanitizers and disinfectants).
So unless the biofilm is addressed, then conventional cleaning efforts are a waste of time because the pathogen bacteria will be largely unaffected and the any weakening of the biofilm from such approaches will only result in its rapid rebuilding.
Prof Green in one of her TED Talks about her research notes that humans eat yogurt to restore / strengthen the microbiome of their gut to make them healthier. She then raises the point that what is needed is “Yogurt for Buildings”.
This is a logical approach. The conventional approaches of using just Physics and Chemistry are clearly proving increasingly in adequate. The issue of HAI / HAC is one evidential exhibit, and the appearance in such HAI / HAC infections in non-hospital environments such as schools is another.
What Prof Green is calling for here is the addition of a Biology component to cleaning; the idea of “fighting fire with fire”.
“Microbiology 101” is the appreciation that no matter how big or large the “chemical hammer” when trying to address a micorobe, eventually the microbe will adapt and win out over the “chemical hammer”, or in the case of HAI / HAC the Chemistry used to prevent such issues by trying to kill all the bacteria, good and bad.
So is there a Biology based solution to these challenges of HAI / HAC?
The emergence and use of Probiotic bacteria based cleaning agents suggests so. Such cleaners have been successfully used in areas where biofilm is a massive problem such as agriculture (poultry, hog and dairy barns) for 7 yrs, and restoration of HVAC heat exchange units (coils, chillers and cooling towers) for 4 yrs demonstrates that this approach is successful in addressing pathogen biofilm.
I find it ironic that such cleaners are saving the lives of pigs, poultry and dairy cattle but are not even being considered by the commercial cleaning and healthcare sectors to save human lives.