Biofilms in the Home and Their Impact on Human Health

We’ve talked a lot about mold and how important it is to prevent its spread in the home. Mold is indeed one of the most serious threats to our health, but the problem doesn’t end there. Recent research shows that we shouldn’t only be talking about mold, but about a broader issue — homes affected by water damage.

You may say: “But that’s exactly how the mold problem starts!” And that’s true. However, besides mold, there are other threats that often go unnoticed. In addition, if you think the problems are limited to roof leaks, basements, or sewage systems, you are underestimating the scale of the issue.

This has become a large-scale problem relatively recently and is directly related to the increase in our level of comfort. In the past, homes didn’t have running water, sewage systems, dishwashers, refrigerators, or washing machines. Basements and attics existed, but there was no central heating. No one tried to wrap a house in plastic to minimize heat loss. Homes weren’t airtight, they “breathed,” which reduced the risks we are about to discuss. All of these changes happened recently, and they created ideal conditions for the growth not only of mold but also of other microorganisms. That is why it is more accurate to speak not only about the problem of mold indoors, but about the problem of biofilms that form in that environment.

And that’s exactly what we’re going to talk about now. The first article will be dedicated to biofilms in our homes, and the second will explain what you can do to keep your home from becoming “sick” and making those who live in it sick. “Sick building syndrome” is a fully recognized illness, but I have yet to hear of our Canadian medical system ever diagnosing or treating it.

What are biofilms and how can biofilms affect the indoor air environment?

• Biofilms are complex communities of microorganisms that form on surfaces in the presence of moisture. In a water-damaged home, biofilms can form on any wet or moisture-prone surfaces, including walls, floors, ceilings, pipes, and household appliances. Microorganisms within biofilms interact with each other and with the surrounding environment, forming a resilient structure that protects them from external influences.
• Microorganisms that make up the biofilm: A biofilm can include various types of microorganisms, such as mold, bacteria, viruses, and actinomycetes. In conditions of elevated humidity in a water-damaged home, these microorganisms find an ideal environment for growth and reproduction. Mold and actinomycetes are especially common in such conditions, as they can easily thrive on porous and damp materials.
• The protective matrix of a biofilm and its resistance: Biofilms form on wet or moisture-prone surfaces. They are surrounded by a protective matrix composed of polysaccharides, proteins, and other substances secreted by the microorganisms. This matrix shields the microorganisms from external factors such as cleaning agents and antimicrobial products, making the biofilm particularly resistant and difficult to remove. This requires the use of specialized cleaning and disinfection methods.

Mold, actinomycetes, and endotoxins: differences and effects on health

Mold and actinomycetes are microorganisms that are often found in environments with high humidity, such as homes affected by flooding. Although both types of organisms can cause health problems, they differ in their effects and properties.

Mold is a fungus that grows on organic materials such as wood, paper, and fabric. Mold produces spores and hyphae that spread through the air and settle on various surfaces. It releases mycotoxins — toxic substances that can cause allergic reactions, asthma, and other respiratory problems. Mold also creates biofilms on damp surfaces, making it particularly difficult to remove.

Actinomycetes are bacteria that look like long threads and live in soil and in homes affected by water damage. They play an important role in the decomposition of organic matter and the production of antibiotics. Although their metabolites are not classical toxins, they can disrupt the body’s microbiome and cause respiratory problems. Actinomycetes also form biofilms, which complicates their removal and control.

Endotoxins are toxic substances released from the cell walls of gram-negative bacteria when they break down. They can cause acute inflammatory reactions and serious illnesses such as sepsis. It is important to note that endotoxins and the metabolites of mold and actinomycetes represent different problems.

Mycotoxins from mold and actinomycete metabolites can both affect health, but in different ways. For example, mold releases substances that cause allergies and breathing problems, while actinomycetes can disrupt the microbiome and lead to respiratory diseases.

Understanding the differences between mycotoxins, actinomycete metabolites, and endotoxins helps to more effectively cope with their effects and take steps to improve air quality and maintain health indoors.

Possible causes of water damage in homes followed by biofilm formation

In the context of a water-damaged home, biofilms can present a serious problem, especially if moist conditions persist for an extended period. Biofilms formed by microbes such as bacteria and mold can appear on various surfaces, including walls, floors, ceilings, and inside ventilation systems.

• The impact of severe storms on water supply and home structure: Hurricanes and typhoons can damage plumbing systems, compromise the integrity of home structures, and lead to flooding, creating favorable conditions for biofilm formation.
• Impact on basements and lower levels of homes: Heavy rains and river overflows can flood basements and lower floors, increasing humidity and creating ideal conditions for biofilm growth.
• How sewer blockages contribute to biofilm formation: Clogs in sewage systems lead to stagnant water, promoting the proliferation of microorganisms and the formation of biofilms.
• The impact of leaks on ceiling and wall structures: Roof leaks can lead to moisture in ceilings and walls, creating an environment for biofilms to grow on these surfaces.
• Cracks in tile and leaks in plumbing/sewage: Cracks in tile, as well as small leaks in water supply and sewage pipes, promote the accumulation of moisture in hidden areas, leading to the formation of biofilms.

How do biofilms in indoor environments affect health?

• Respiratory diseases. Biofilms can release microparticles and allergens that, when inhaled, irritate the respiratory tract, causing chronic cough, asthma, and allergic reactions. Continuous exposure to these irritants can lead to the development of serious respiratory conditions.
• Infectious risks. Biofilms often contain pathogenic microorganisms such as bacteria and fungi, which can infect people through contact or inhalation. This increases the risk of infectious diseases, especially in individuals with weakened immune systems.
• Toxic emissions. Mold, as part of biofilms, releases mycotoxins — toxic substances that can enter the body through the respiratory tract or skin. These toxins can cause a wide range of symptoms, from headaches and fatigue to more serious disorders such as liver and kidney damage.
• Impact on the immune system. Constant exposure to microorganisms and toxins released by biofilms can cause chronic inflammation, which burdens the immune system. This can lead to a disruption of normal immune responses, reduced ability to fight infections, and an increased risk of autoimmune diseases.
• Hormonal disorders. Components of biofilms, such as mycotoxins released by mold, as well as other chemicals, can act as endocrine disruptors. These substances can interfere with the endocrine system, leading to hormonal imbalances, including altered stress levels, reproductive issues, and thyroid hormone disruptions.
• Neurological disorders. Substances released by biofilms can have toxic effects on the nervous system, causing memory impairment, decreased concentration, dizziness, and chronic fatigue.
• Cardiovascular diseases. Long-term exposure to polluted air in buildings with biofilms can contribute to inflammation of blood vessels, increased blood pressure, and a higher risk of cardiovascular disease.
• Skin reactions. Contact with contaminated surfaces or inhalation of biofilm particles can cause skin irritation, dermatitis, and worsening of chronic skin conditions.

Why has the problem of pathogenic indoor biofilms become relevant now?

• Impact on humidity and the microbiome of homes: In the past, homes didn’t have sewage systems, running water, or central heating. The absence of modern utilities historically resulted in different humidity conditions and the formation of a completely different microbiome.
• Modern building materials: The use of new building materials and technologies has influenced the development and spread of biofilms, as they can create conditions for moisture accumulation. Drywall covered with paper, paper and vinyl wallpaper, insulation materials such as mineral wool or fiberglass, laminate and parquet flooring, modern water-repellent paints, plastic and vinyl windows.
• Increased airtightness of homes: Modern energy-efficiency measures that involve sealing homes contribute to higher indoor humidity, which in turn promotes biofilm growth.
• Washing machines, dishwashers, refrigerators with auto-defrost: These appliances can become sources of elevated humidity and favorable environments for biofilm growth inside them.
• Increased use of household appliances and more time spent indoors: The modern lifestyle and increased time spent indoors exacerbate the problem of biofilms, as homes develop additional sources of moisture.

Conclusion

The problem of biofilms in water-damaged homes is becoming increasingly relevant. These complex communities of microorganisms, forming on damp surfaces, pose a serious health threat. They can cause respiratory diseases, infections, toxic reactions, and immune system disorders. Given modern construction standards and increased building airtightness, it is important not only to fight mold but also to take measures to prevent and control biofilms. We can no longer give up this comfort, so we need to learn how to live in these conditions without exposing ourselves and our loved ones to excessive risks.

In the next article, we will look at practical recommendations for protecting your home from these dangerous microbiological threats: Creating a Safe Home Environment for Better Health