Medical Literature Library

The Truth About Microbes

Microbes are tiny living organisms that live almost everywhere on this planet, including the human body. The human microbiota is diverse and includes bacteria, viruses, and eukaryotes, such as fungi, helminths, and protozoa. Microbes play an important role in human health, as they can aid in essential functions like digestion and nutrient cycling. However, some can also be associated with major health issues.


So, what is the human microbiota, and what does the general public need to know about it? This article will focus on the nature of the skin microbiome and its constituents and endeavor to clear up some common misconceptions about it. The skin biome encompasses all living actors on the skin, including the skin cells themselves, while the skin microbiome includes the microbes that populate the skin biome.


The Five Different Types of Microbes


1. Bacteria: Bacteria are single-celled microorganisms. As prokaryotes, they have cell walls but lack organelles and an organized nucleus. Based on current scientific knowledge, bacteria in the microbiome represent the majority of microbes in the skin. 


2. Fungi: Fungi are eukaryotic microbes and are key contributors to core functions related to developing, maintaining, and repairing the skin. Although some helpful fungi can live on the skin without any issues, overgrowth or microbiome imbalance can lead to skin conditions such as acne and dermatitis. 


3. Archaea: Archaea are single-celled microorganisms that share many of the same physical characteristics as bacteria and eukaryotes. While archaea aren’t generally understood to cause disease, we aren’t completely certain what role they play in the skin microbiome. There is some evidence that the prevalence of archaea on the skin increases with age, although researchers have yet to determine the significance, if any, of this discovery. 


4. Protozoa and Helminths: Protozoa are a group of single-celled eukaryotes that feed on organic matter, and helminths are microscopic worms. These microbes are primarily associated with disease, but it is possible they may play a part in maintaining the human body’s microbiome. 


5. Viruses: Viruses are the smallest known microbes and are not considered to be “alive” in the usual sense of the word. Viruses can’t survive on their own and can multiply only by infecting a living cell and using it to reproduce. They typically consist of genetic material like DNA, RNA, and proteins packaged in a type of shell used to deliver the contents into the target cells. Researchers haven’t committed much time to examining viruses’ impact on the skin microbiome. However, one class of viruses, the bacteriophages, doesn’t infect human cells but only the bacteria of the microbiome.


Microbes: Good, Bad, or Neutral?


Although our skin does a good job protecting us from external threats, it’s not an impenetrable barrier. Some of the microbes in and on our skin simply live there and may not be beneficial or detrimental to our health. Other microbes that reside in and on the skin are symbiotic in nature and perform or assist with vital protective and preservative functions. Unfortunately, the collection of microbes in the skin can include some bad actors which have the potential to cause health issues, but the good news is that often the symbiotic and commensal microbes keep the potentially harmful ones in check. Regardless, the situation isn’t as simplistic as “germs cause disease.”


For example, Staphylococcus epidermidis is a common skin bacteria species. Some strains of this species have been reported to produce antimicrobial compounds that protect against harmful strains, such as ones associated with methicillin-resistant Staphylococcus aureus (aka MRSA). On the other hand, some strains of Staphylococcus epidermidis have been highly associated with hospital-acquired infections. So, the strain of a microbe is a very important consideration as to how it affects our health, but it’s not the only one. We also must evaluate how those strains interact with other strains and whether our immune system is working properly to deal with potential conflicts within the skin ecosystem. As one can see, we can’t simply call a microbe either good or bad; there is more to the issue. 


Why Microbe Diversity Is Critical to Skin Health


When it comes to the skin biome, balance is the most important aspect. Microbial balance is critical to skin health because different types of microbes play different roles in maintaining a healthy skin microbiome. What is microbial balance? A healthy skin microbiome includes a diverse collection of microorganisms living on the skin’s surface which collaborate to protect the skin from harmful pathogens and maintain the skin’s barrier function.


Research indicates that a diverse skin microbiome is associated with healthier skin, while a less diverse microbiome is linked to skin conditions such as acne, eczema, and psoriasis. This is because a diverse skin microbiome is better equipped to carry out the various functions required to maintain skin health, such as regulating the skin’s pH balance, producing antimicrobial compounds, and interacting with the immune system. However, the advantage of diversity is not always the case, depending on the part of the skin. Research has shown that more diversity is associated with skin issues like acne in the hair follicles.


Several things can affect the balance of the skin biome. Numerous factors, including genetics, age, diet, hygiene, and exposure to environmental stressors, influence microbe diversity on the skin. Maintaining a balanced and healthy skin microbiome is achieved through practices such as not over cleansing the skin and washing with gentle cleansers containing minimal surfactants. Also, it is important to avoid using antibacterial ingredients or products unless directed to do so by a personal physician.


The Consequences of Microbiome Disruption


While no one needs to be an expert in microbiology, having a cursory understanding of how the skin biome and all the tiny microbes in it work and how to best keep it healthy is a good idea. This task is essential since an imbalance in the microbiome called skin microbiome dysbiosis may trigger health issues, such as inflammatory diseases of the skin and gut, allergies, and certain cancers.


Unfortunately, these diseases are why the general public instinctively associates microbes with health conditions. Keep in mind that as much as microbiome disruption is certainly a precursor to illness, a symbiotic relationship between the immune system and helpful microbes is just as critical to maintaining healthy skin. 


It’s clear that each species of bacteria consists of several strains or subspecies, each with distinct physiological traits and activities that might be considered good or bad, depending on how those traits present and when and where those activities occur. As medical professionals continue to modulate the skin microbiome to treat skin disease, knowing which bacterial strains to target might be the key to successful treatment.


In summary, skin biome balance is critical to skin health because a balanced skin microbiome is better equipped to carry out the functions required to maintain healthy skin and protect against harmful pathogens. As with all things, recognizing nuance is essential to forming an accurate picture of the skin biome.


Thomas Hitchcock, Ph.D., is the Chief Science Officer for Crown Laboratories, where he oversees clinical development, medical affairs, biological sciences, product development, and research and development for the privately held, fully integrated global company dedicated to developing and providing a diverse portfolio of safe and effective scientific solutions for life-long healthy skin. Dr. Hitchcock is a formally trained scientist with expertise in molecular genetics, microbiology, and dermatology. He has 20+ years of research experience, including basic science, preclinical, and clinical research across several therapeutic areas. He has also been issued patents on his inventions in aesthetic medicine, dermatology, and microbiology. Dr. Hitchcock lectures and presents his research internationally. His work has been published in notable journals such as the “Journal of Biological Chemistry,” “Annals of the New York Academy of Sciences,” “Clinics in Plastic Surgery and Nature,” “Journal of Cosmetic Dermatology,” “Aesthetics Surgery Journal,” “Nucleic Acid Research,” and “Cell Transplantation.” He is also the co-author of the book “Rebooting the Biome”.