A study found that in urban homes, where the use of cleaning products is usually more prevalent than in rural homes, fungal diversity was higher, not lower as might be expected. The study, “Home Chemical and Microbial Transitions Across Urbanization,” was published in the journal Nature Microbiology.1
Researchers investigated and compared the chemical and microbial conditions of urban and rural homes in the Amazon basin and of the people who lived in them.
The dwellings ranged from a rainforest village with thatched huts that had no walls to a Peruvian rural town with wooden houses but no indoor plumbing, to a more populous Peruvian city of 400,000 with more modern appurtenances, to the high-rise dotted metropolis of Manaus, Brazil.2 What the researchers found from the wide cross section of urban and rural living was surprising:
“The degree of urbanization correlated with changes in the composition of house bacterial and microeukaryotic communities, increased house and skin fungal diversity, and an increase in the relative abundance of human skin-associated fungi and bacteria in houses.
Overall, our results indicate that urbanization has large-scale effects on chemical and microbial exposures and on the human microbiota.”3
Cleaning Products May Be Encouraging Fungi
Many people are aware of the serious dangers of antibiotic-resistant bacteria that are caused by excessive antibiotic usage. But do fungi also become resistant to cleaning products and chemicals as the study suggests?
Fungal resistance to cleaning products and chemicals is only one explanation the researchers postulate in the study, but the substances are major suspects.
The researchers also question whether the fungi are flourishing because of the warmer temperatures typically found in urban homes and from other factors more likely to be found in urban homes than less developed housing, like reduced air exchange and lower levels of natural light.
There is even another facet to urbanization that could be at play in the increased fungal presence, says Maria Gloria Dominguez-Bello, a professor in the biochemistry and microbiology department and the anthropology department at Rutgers University-New Brunswick and senior author of the Nature Microbiology research.
Modern living shuts us inside with industrial compounds and higher carbon dioxide levels, she says.4 It is not surprising that being cut off from the healing properties of nature can have negative health consequences. The documentary, “Call of the Forest — The Forgotten Wisdom of Trees,” revealed how forest bathing produces positive psychological and physiological effects and trees boost the immune system by emitting specific and healthy compounds.
Similarly, in the documentary “Down to Earth,” grounding or earthing, in which foot contact is made with the Earth without shoes, is found to neutralize free radicals in the body through access to the negatively charged electrons in soil.
Grounding is also said to reduce the unwanted voltage humans can receive from electromagnetic fields that are ubiquitous in developed countries.
Urbanization Includes Many Harmful Factors
As would be expected, the researchers found molecules from medications and cleaning agents in urban homes but not in the rural or rainforest homes. And researchers made another fascinating discovery: In rural or rainforest homes, there was a greater variety of bacteria and fungi that live outdoors and fewer that colonize the human body and are harmful.
A study in Science Advances confirms the presence of desirable microbes in the gut microbiomes of those living in isolated areas and less touched by urbanization, but surprisingly also points out the existence of antibiotic resistance genes:5
“Most studies of the human microbiome have focused on westernized people with life-style practices that decrease microbial survival and transmission, or on traditional societies that are currently in transition to westernization.
We characterize the fecal, oral, and skin bacterial microbiome and resistome of members of an isolated Yanomami Amerindian village with no documented previous contact with Western people. These Yanomami harbor a microbiome with the highest diversity of bacteria and genetic functions ever reported in a human group.
Despite their isolation, presumably for >11,000 years since their ancestors arrived in South America, and no known exposure to antibiotics, they harbor bacteria that carry functional antibiotic resistance (AR) genes, including those that confer resistance to synthetic antibiotics and are syntenic with mobilization elements.
These results suggest that westernization significantly affects human microbiome diversity and that functional AR genes appear to be a feature of the human microbiome even in the absence of exposure to commercial antibiotics.”
A decline in the richness of humans’ microbiomes may be linked to the increase of immunological and metabolic diseases such as asthma, allergies, diabetes and obesity in recent years, points out Dominguez-Bello.6 Even autism is associated with urbanization, which in turn is linked to a loss of microbiome diversity.7
Western Medications Deplete Beneficial Bacteria
The repeated use of antibiotics, seen in urban environments and seldom in rainforest and rural environments, may raise the risk for Type 2 diabetes by altering gut bacteria, write researchers in the European Journal of Endocrinology:8
“Treatment with two to five antibiotic courses was associated with increase in diabetic risk for penicillin, cephalosporins, macrolides and … The risk increased with the number of antibiotic courses.”
There are other gut microbiome risks from urbanization. Pesticides, processed food and Caesarean sections may also contribute to the dramatic decline in the richness of the human gut microbiome. These factors are seldom seen in less developed cultures but abound in urban environments.
In fact, one study even suggests that sophisticated sanitation and sewage systems, the hallmark of developed cultures, may be a factor in destroying microbial diversity, perhaps more consequentially than antibiotics.9
Human Fungal Infections Are Increasing
In the last few decades, fungal infections have increased, mostly because of the growing population of immunocompromised individuals undergoing intensive chemotherapy and those with HIV.10 One fungal disease, Cryptococcosis, has become strongly associated with immunocompromised HIV patients.11
But in 1999, a different species of fungus called Cryptococcus gattii or C. gatti surfaced and it was not linked to HIV patients. Previously a tropical disease, C. gattii began to infect healthy individuals across the Pacific Northwest, leading doctors to wonder if environmental change could increase the domain of some fungal pathogens.12
Then in 2009, Candida auris, a deadly yeast fungus no one had ever encountered, emerged. First described in a Japanese patient with an ear infection, it has since become a rapidly spreading pathogen, especially ominous because it is often multidrug-resistant.13
C. auris mostly affects those who are already seriously ill and kills one-third of those it infects.14 Its multidrug-resistance means hospitals have a difficult time eradicating it.15 The origin and spread of C. auris is unprecedented, says NBC News:16
“C. auris didn’t spread like a virus would, radiating out from one location. Instead, it popped up simultaneously in different parts of the world, including India, South Africa and South America.
‘It was really mystifying that Candida auris appeared at the same time in three continents,’ said … Dr. Arturo Casadevall, chair of the molecular microbiology and immunology department at the Johns Hopkins Bloomberg School of Public Health.
Casadevall and his team thought the fungus’s emergence must have been the result of some kind of change in the Earth’s environment — in this case, a gradual rise in temperature.”
What is especially odd, says NBC News, is that fungi normally gravitate toward the coolest parts of the human body like feet and nail beds. In the past, fungi didn’t cause internal infections because they can’t survive the body’s warmer temperatures, which hover around 98 degrees Fahrenheit. Now, this may be changing.17
Fungicides May Be a Factor in the Fungal Boom
The emergence of aggressive, drug-resistant fungi could also stem from fungicides used agriculturally. The chemicals are widely used in farming. Mother Jones states:18
“According to data collected from US government sources by the pesticide-tracking group Hygeia Analytics … 62 percent of total US peanut acres were treated with the triazole fungicide tebuconazole in 2016, and 25 percent with another one, propiconazole.
Both were named in a 2013 Dutch study among five farm fungicides identified as a driver of resistance in hospital-acquired A. fumigatus infections among patients with no previous exposure to the chemical.
The use of fungicide propiconazole jumped nationwide from less than a half-million pounds in 2004 to more than 2 million pounds in 2016, according to the US Geological Survey. It’s used on soybeans, wheat, rice, fruits, vegetables, and orchard crops.”
The wide use of chemicals with one specific means of killing fungi in agriculture, known as single-target-site fungicides, could morph into more drug-resistant fungal infections in humans, say experts.19
In Europe, the Americas and Asia, drug-resistant strains of the fungus Aspergillus fumigatus have also been found. Since drug-resistant Aspergillosis has even been identified in patients who have never been treated with antifungals, environmental sources are suspected.20
Spread of Fungal Infections Is an Environmental Red Flag
The spread of fungal infections raises many questions. The discovery of a greater incidence of fungi in urban areas suggests that the pathogens may be becoming resistant to cleaning products or even opportunistically replacing bacteria that have been eliminated since, as they say, “nature abhors a vacuum.”
The preponderance of the urban-located fungi also highlights the unhealthy aspects of urban living. Major questions also exist about environmental change and the use of agricultural fungicides, both of which could be causing or contributing to fungal resistance. The phenomenon of antibiotic-resistant bacteria from excessive farm use in livestock is well-documented and another significant danger.
How Can You Avoid Infections?
Minimizing your use of antibacterial cleaners may help protect the natural diversity of microorganisms in your home and on your body, but you can also help to avoid infections — including fungal infections — by boosting your immune system. Toward this end:
- Exercise regularly — Exercise improves the circulation of immune cells in your blood. The better these cells circulate, the more efficient your immune system is at locating and eliminating pathogens in your body. Make sure your fitness plan incorporates weight training, high-intensity exercises, stretching and core work.
- Get plenty of restorative sleep — Recent research shows sleep deprivation has the same effect on your immune system as physical stress or disease,21 which is why you may feel ill after a sleepless night.
- Have good stress-busting outlets — High levels of stress hormones can diminish your immunity, so be sure you’re implementing some sort of stress management. Meditation, prayer, yoga and the Emotional Freedom Techniques (EFT) are all excellent strategies for managing stress, but you’ll have to find what works best for you.
- Optimize your vitamin D levels — Studies have shown that inadequate vitamin D can increase your risk for MRSA and other infections,22 which can likely be extended to other superbugs. Your best source of vitamin D is through exposing your skin to the sun, but supplementation may also be necessary.