Bacteria still cause a “gross” factor in many people. Every day we attack them before, and after we go to the toilet, while showering, with hand disinfectant, while washing up, the list goes on. Most, however, are familiar with yogurt or other probiotic products that are said to be full of “good” bacteria. To better know the good and bad of bacteria, let’s explore the self-appealing creatures that live on our skin.
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Our Skin Is A Dynamic Ecosystem
The skin is our largest organ. It’s a dynamic shield full of nerve endings that allow us to feel the world while protecting ourselves from extreme temperatures, ultraviolet rays, toxins and pathogens while keeping water and nutrients inside. There are 3 layers: the epidermis (outer), dermis and subcutis (base).
The epidermis made up of cells known as keratinocytes that form layers of varying thickness depending on the location of the skin. This is also where Langerhan cells located, which help to investigate pathogens and regulate our immune system. The epidermis is also an excellent defence for us against the outside world.
With its collagen and elastin, the dermis acts like a rubbery part and gives our skin elasticity and firmness. There are also nerve receptors here that send information to the brain about touch, temperature, and pain. Also, there are too many secretory glands here. There are three main types of secretory glands: eccrine, apocrine, and sebaceous glands. Eccrine glands abound on all surfaces of the skin and are responsible for regulating body temperature through sweat.
They also inhibit microbial growth by acidifying the skin. Apocrine glands, on the other side, are found in areas with more hair follicles like armpits, nipples, and genital areas. They excrete milky fluids that are often associated with psychological arousals, such as B. Stress or sexual arousal. When bacteria attack the secretions of the apocrine glands, people often look to deodorants. Finally, the sebaceous glands secrete an oily and waxy substance called sebum that covers and protects our skin and hair.
After all, the base layer made up of fat and connective tissue to insulate and cushion us while serving as a fuel reserve.
What Is Your Skin Flora?
Skin Flora refers to minor microbes that found on your skin. This includes bacteria, viruses, and fungi (to find out the difference between the three groups, visit here). Mites also settle on our skin. Together, the flora on your skin can act as a barrier to other invading bacteria, which may or may not cause disease. Sometimes the flora on your skin is also a source of infection.
What Is The Difference Between “Good” And “Bad” Microbes?
Much literature tries to differentiate between “good” and “bad” microbes. For example, “bad” bacteria can have DNA-coding properties to bypass our immune systems, pump out antibiotics, or change where antibiotics would bind so that they can no longer do so. My favourite explanation, however, is “depending on the place and time”, which I learned from an introductory microbiology course. Like many living organisms, bacteria want to survive and multiply. Like a right Darwinian species, it adjusts to its surroundings, from deep-sea springs to hot springs to your iPhone. The “bad” bacteria adapt to live within us in ways that have adverse consequences. Also, “good” bacteria adapt in ways that we believe are beneficial. In many ways, we are just Petri dishes to bacteria.
What Lives On Our Skin?
Our skin generally described as a cold, acidic and dry habitat and it also shows variations that lead to a different flora depending on the number of hair follicles, the folds and the thickness of the skin. Most of the skin bacteria found to fall into four main categories / “Phyla”, which are known as Actinobacteria, Firmicutes, Bacteroides, and Proteobacteria.
- In hot, humid places where the skin is partially covered (groin, armpits, toe nets), bacteria that like high humidity include Corynebacterium, Staphylococcus aureus, and gram-negative bacilli *. Our smell of sweat is most likely associated with corynebacteria and staphylococci, which feed on the secretions of the apocrine glands.
- On our face, back and chest, where there are more concentrated sebaceous glands, the fungi Propionibacterium. And Malassezia are some of the bacteria that feed on sebum. These regions also have the lowest bacterial diversity. Demodex mites even live in these regions.
- In drier areas such as arms and legs, the microbial density is lower due to large fluctuations in temperature. These also placed with more skin variety with representations of the four species mentioned above.
- Babies born by cesarean section tends to have a flora associated with the skin, while babies born vaginally tend to colonized with the vaginal flora of their mothers. These skin florets change as babies interact with their environment and grow.
Other factors that affect skin flora:
- Host factors like age and sex, as well as underlying diseases and immune susceptibility
- Environmental factors such as weather and geographic location
- Lifestyle choices like jobs, hygiene practices, antibiotic use, hand, clothing, UV exposure, cosmetic services, and more.
“Bacteria traditionally derived as either Gram-positive or Gram-negative, depending on the structure of the cell wall, which means that they stain differently when stained. Gram-negative rods appeared as pink bacilli and previously believed to rarely colonize our skin.”
What Protective Functions Do Microbes Play On Our Skin?
The dermis or bacteria on our skin are always in balance with our immune system, and this accomplished through a large amount of crosstalk involving secreted molecules and complex immune pathways. They help regulate our immune system by “training” our immune cells to differentiate between pathogens and residents. Also, some bacteria in the skin flora secrete antibacterial substances to prevent others from living on our skin and can sometimes work with our immune system to speed up the elimination of pathogens.
What Harm Can Microbes Do To Our Skin?
Since there is constant interference between microbes on the skin and our immune system, illnesses are suspected when chi disrupted. For example:
- Seborrheic dermatitis is an itchy and scaly skin condition/peeling that occurs primarily on the scalp. Malassezia mushrooms believed to involve in this process, and patients often see an improvement with antifungal medications.
- Open wounds and wounds contribute to the flora of our skin in our body. For example, Staphylococcus epidermidis often associated with infected medical devices such as catheters and heart valves.
- Propionibacterium acne believed to be the cause of lousy acne during puberty when our sebum glands mature. The hypothesis is that the increase in sebum glands means an increase in sebum, which P. acnes in excess attracts and selects. This leads to irritation of the pilosebaceous glands as the bacteria communicate with the immune system and produce unsightly pimples. However, more studies needed on this link.
Our skin microbiota is an exhilarating and dynamic area where researchers continue to find better methods and analyze the wealth of our data. It is vital to note that the correlation is not causal, especially when it comes to the flora of our skin (just because a bug often linked to a disease doesn’t mean the bug caused the disease). The best one you can do is to keep your skin healthy is to keep reading up on current literature while staying open-minded.