The Invisible Residents of Our Skin, Getting to Know Skin Microbiota!
What is Skin Microbiota?
The skin is the body's outermost organ, acting as a protective barrier between the human body and its environment. Interestingly, each area of the skin has distinct characteristics.
For example, the temperature in areas such as the groin and armpits can reach 37°C, while the fingertips and toes are more fabulous, around 30°C. Sebaceous glands in the skin produce fatty acids that help maintain an acidic pH (ranging from 4.2 to 7.9), creating an ideal ecosystem for various microorganisms.
These conditions allow microorganisms (bacteria, fungi, viruses, and archaea) to thrive on the skin. This diverse community, known as the skin microbiota, is crucial in wound healing, infection prevention, and overall skin health.
However, its balance can be disrupted by aging, skin diseases, or external factors. Understanding the skin microbiota remains a significant challenge in health and cosmetics. However, advancements in modern technologies, such as next-generation sequencing (NGS), have opened new opportunities for research and innovation.
Types of Skin Microbiota
Without realizing it, our skin hosts diverse microorganisms that form a unique ecosystem. The skin microbiota consists of various types of microorganisms, including bacteria, fungi, viruses, and archaea:
1.Archae
The most commonly found types are Thaumarchaeota and Euryarchaeota, which help regulate skin pH and strengthen the body's natural defense system.
2.Viruses
Bacteriophages, or viruses that infect bacteria play a role in controlling bacterial populations. According to a study by Liu et al. (2017), individuals with healthy skin have more Cutibacterium acnes phages than those with Acne vulgaris. This suggests that phages help prevent the growth of acne-causing bacteria.
3.Bacteria
Human skin is predominantly colonized by bacteria from the genera Staphylococcus, Corynebacterium, and Cutibacterium, which work together to maintain skin homeostasis.
What is the Role of Skin Microbiota?
Skin microbiota are not only passive residents but also have important functions. They play a role in maintaining skin homeostasis, which protects against pathogens and environmental problems.
Microbes on the skin produce protease enzymes that help exfoliate dead skin cells and renew the outermost layer of skin (stratum corneum). In addition, the lipase enzyme produced also helps break down the fat layer on the skin's surface, and the urease enzyme plays a role in breaking down urea.
Another role of microbes on the skin as a homeostatic defense is to protect the skin from pathogens through a competition mechanism, namely, microbes competing for a place to live and nutrients. Another mechanism is to produce antimicrobial substances such as antimicrobial peptides (AMP).
In addition to maintaining skin homeostasis, skin microbiota can interact with the human immune system. Since the beginning of life, bacteria on the skin have had a strong interaction with the body's immune cells; T immune cells in the skin are trained to respond to pathogenic bacteria that appear temporarily on the skin.
What Affects the Composition of Skin Microbiota?
The composition of skin microbiota is not stable. Various factors, ranging from hereditary factors to daily habits, can affect the balance of microorganisms on our skin. Intrinsic and extrinsic factors influence the composition of skin microbiota.
Intrinsic Factors
Intrinsic factors that affect skin microbiota composition include skin location, ethnicity, gender, and aging. Based on skin location, areas that tend to be oily, such as the face, will be dominated by Propionibacteria and Staphylococci.
Corynebacteria and Staphylococci will dominate moist skin areas (armpits). At the same time, dry skin areas have higher microbial diversity.
Ethnicity factors include behavioral patterns, cultural aspects, and social aspects. For example, Corynebacterium variable is found in Hispanics, while Corynebacterium kroppenstedtii is more common in East Asians.
Based on gender, men's skin tends to have more Cutibacterium and Corynebacterium, while women have more Enterobacteriales and Moraxellaceae. Corynebacterium increases in older skin, while Cutibacterium decreases.
Extrinsic Factors
Extrinsic factors are the environment and habits of a person that affect the skin microbiota. These factors include the birth process from infancy to development according to the environment. Lifestyle and hygiene, such as using cosmetics and soaps and exposure to pollution, will also affect microbiota diversity. People who live together tend to have similar skin microbiota. In addition, antibiotics will reduce the number of bacteria and allow pathogenic bacteria to grow.
The skin microbiota is an essential element in human health. A deeper understanding of the skin microbiome paves the way for clinical applications (such as microbiome-based therapies) and industry (such as developing microbial-based cosmetics). However, many technical and methodological challenges exist in exploring and manipulating it effectively.
To understand the composition of the skin microbiota more accurately, IML Research provides molecular biology testing services. This test helps identify microorganisms on the skin, providing essential insights for developing cosmetic products or other products you have.
References:
Boxberger, M., Cenizo, V., Cassir, N., dan Scola, B. L. 2021. Challenges in exploring and manipulating the human skin microbiome. Microbiome, 9: 125.
Grice EA, Kong HH, Conlan S, Deming CB, Davis J, Young AC, et al.Topographical and temporal diversity of the human skin microbiome.Science. 2009;324:1190–2.
Liu J, Yan R, Zhong Q, Ngo S, Bangayan NJ, Nguyen L, et al. The diversity and host interactions of Propionibacterium acnes bacteriophages on human skin. ISME J. 2015;9:2078–93.
