Skin Flora For Beautiful Skin

Table of Contents

What is skin flora?

The skin flora is the types of microorganisms which reside on your skin. They are frequently referred to as the skin microbiome or skin microbiota.

Your skin has large numbers of these microorganisms on it. In total, there are 10 times more microorganisms than your own body cells!

Your skin hosts more microorganisms on your skin than anywhere else on your body, apart from your gut. Though bacteria are the most numerous of these microorganisms, mites, viruses and fungi also form a part of the skin microflora of a normal healthy human.

Human microbes

In brief, the microbes found on human skin are categorized into three groups:

1. Transients

These microorganisms are found intermittently on the human skin. They either don’t replicate or their growth rates are so low that they are not capable of sustaining their presence on the skin. Occasionally, they may only be isolated in cultures of skin samples and include Gram-positive bacteria such as clostridia which are found in the perineum.

A variety of factors influence transient skin microflora including skin characteristics such as pH, and dryness of the skin. Hot, humid weather conditions also lead to an increased number of transient microflorae on the skin. Similarly, personal hygiene is also a factor as unclean persons tend to have a greater number of transient microflorae. Age, too, plays a role and children tend to have a higher number of transient microflorae than adults.

2. Temporary residents

These microorganisms can maintain a growth rate that allows them to remain on the skin for a short duration.

3. Resident microorganisms

Resident microorganisms inhabit your skin permanently. They are considered true, normal, skin microflora. They’re able to survive, multiply and live on the skin. Usually, resident microorganisms are present in the upper part of the epidermis and are clustered in and around hair follicles.

It is presumed that resident skin microflorae have evolved in the skin’s environment. These include mainly gram-positive bacteria such as propionibacterium, brevibacterium, and others. Gram-negative bacteria are also resident bacteria and are present on your skin in limited areas. As an example, a resident microorganism that is highly prevalent on the skin is a yeast known as Malassezia.

How does skin flora come to the body?

The ecology of the skin surface drives the colonies of various microorganisms. However, this is variable and depends on the topographical location, external environmental factors and internal host factors.

Age has a huge effect on the microflora present on the skin. In the uterus, a fetus’s skin is sterile, but colonization from microorganisms occurs immediately post birth if the child is delivered vaginally. Organisms found in the mother’s vaginal canal colonize the baby’s skin. This also occurs a few minutes after birth if the child is delivered by Cesarean delivery. (The baby’s skin is colonized with organisms that reside on the mother’s skin.)

The child receives most of the good microorganisms (both for the skin and the gut) from the mother and the environment at the time it is born. For this reason, many nurses and hospitals prioritize breastfeeding and contact of the baby’s skin to the mother’s skin during the initial months post delivery. This also helps in building the baby’s natural immunity through the mother’s skin and body microbes. The microflorae are also acquired through contact with the surroundings during daily life, for instance, animals, plants, chemicals and people.

During the first few years of life, the microbial communities on the skin establish and stabilize themselves as the newborn baby explores his environment and his immune system matures.

Where on the human skin is microflora found?

Skin is an organ of the human body that helps to protect us from environmental pathogens and reduces excessive water loss from the body at the same time. Some of its other functions include insulation, sensation, temperature regulation and vitamin D synthesis.

The skin consists of the epidermis, fat cells and dermis.

Epidermis

The epidermis is the outermost skin layer. It provides a waterproof barrier that also creates the skin colour. The epidermis contains dead cells, which do not have nuclei. These cells are in constant contact with environmental microorganisms.

The epidermis does not allow these microorganisms to enter the skin’s deeper layers. It is usually impermeable to these microorganisms. However, cuts, wounds and abrasions on the skin’s surface may allow microorganisms to penetrate.

Dermis

The dermis lies underneath the epidermis and contains the connective tissues. It cushions the body from strain and heat and contains sweat glands, sebaceous glands, nerve endings and hair follicles. Also, the dermis contains the lymph nodes and blood capillaries.

Sebaceous glands are present around the hair follicles and they produce an oily substance known as sebum, which lubricates the hair and the skin.

The sweat glands consist of long, hollow, coiled tubes. The coiled portion is located in the dermis and the long portion connects to a pore located on the outer surface of the skin.

There are two types of sweat glands: apocrine and eccrine glands.

  • Eccrine glands are present all over the body, especially on the palms of the hands, forehead and soles of the feet.
  • Apocrine glands are present in the groin, the underarms and around the nipples. They end in hair follicles instead of skin pores.

Hypodermis

The hypodermis helps to attach the dermis to the bones that lie beneath. It consists of connective tissues and fat. The functions of the hypodermis are to insulate and pad.

Skin microflorae are present all over the surface of the skin but the type of microorganism varies according to the anatomical site.

Three major types of dry skin sites:

  1. Dry
  2. Oily/ Sebaceous
  3. Moist

1. Dry sites of the body

Dry sites include the hands, legs, forearms and feet. The predominant organisms at these sites are Coagulase-negative staphylococci such as S. hominis and S. epidermedis.

2. Sebaceous or oily sites of the body

Sebaceous sites of the body include the neck, head and trunk, where the sebaceous glands situated in the skin secrete oily sebum. The major microflorae species found in these areas are Staphylococci and Propionibacteria. Demodex mites and the Malasezzia fungus are also present on the oily areas of the face.

3. Moist sites of the body

Corynebacterium and staphylococci are abundant in the moist areas of the folds of the skin including the elbow creases, the areas under the breasts, the groin, and areas in between the toes.

Does every person have the same microflora profile present on their skin?

Everyone has specific and unique skin microflorae contracted during infancy and that has stabilized during adulthood. Some variation occurs due to environmental factors and age. The microflorae of the skin change and the variety depends on the location. In addition, they vary according to the amount of light received by the area and whether the region is dry, moist, oily or hairy.

Moreover, the microflorae differ with gender and age. For example, a sweaty, hormonal boy in his teenage years has different microflorae on his skin to a sedentary female in her postmenopausal years.

After birth, the key factors that influence the presence of microflorae on the skin include the following:

  • pH of the skin (normal pH of the skin is somewhat acidic at around 4-4.5)
  • Moisture content of the skin
  • Body temperature
  • Ratio of oxygen and carbon dioxide
  • Sun exposure. Ultraviolet radiation damages microorganisms’ DNA.
  • Interaction between different micro organisms present on the skin
  • Internal defences of the host
  • Genetic makeup of the host
  • Kinds of personal and skin care products utilized
  • Exposure to any medicines
  • Exposure to other people

Role of skin flora in human health

Three categories of skin microflora exist.

1. Commensals

These are microorganisms which live on the skin and derive benefit from the host, but the host does not benefit from them.

2. Symbionts

Microorganisms which live on the skin, are beneficial to the host and also, in turn, derive benefit from the host.

3. Pathogens

Skin flora’s presence has certain unwanted consequences, even though most problems are minor and only present for a short duration.  Some microorganisms present on the skin such as corynebacteria, kytococcus, and staphylococci contribute to the general body odour and odours that are specific to certain skin sites such as the axilla and foot. However, some can cause diseases. These include:

  • Propionibacterium acnes causes acne
  • Malassezia spp. causes folliculitis, pityriasis and dandruff
  • Kytococcus sedenterius causes pitted keratolysis
  • Corynebacterium spp. causes erythrasma and trichomycosis axillaris.
  • The importance of Staphylococcus epidermidis is emphasized as it causes serious skin infections in hospitalized patients who undergo surgical procedures that involve the insertion of prosthetic implants and catheters. Immunodeficiency or immunosuppression further increases this risk. 

Are the skin flora in a symbiotic relationship with humans?

According to a study published in the British Journal of Dermatology, microorganisms present on the human skin are usually considered as potential pathogens, pathogens or innocuous organisms that are in a symbiotic relationship with humans. Microorganisms present on the skin that very infrequently cause disease are called commensal.  In other words, the microorganism lives peacefully on the host while getting benefit from it.

For instance, Staphylococcus epidermidis, which is a Gram-positive bacterium, is a commensal. According to emerging evidence, this species of bacteria and other commensals may play a vital role in host defence. They are in a symbiotic relationship with humans instead of being commensals.

How do commensal microorganisms benefit us?

Commensal microorganisms may also help in the prevention of colonization of certain pathogenic microorganisms including S. aureus. Staphylococcus epidermidis produces compounds similar to antibiotics.

  • Commensals reduce nutrients and make toxic compounds, thereby preventing the adherence of pathogenic bacteria to the skin cells.
  • They boost the response of immune cells to pathogenic and harmful bacteria by producing cytokines, interferon and phagocytosis.
  •  Lipoteichoic acid present in the cell walls of Gram-positive bacteria triggers the release of cathelicidin by mast cells. Cathelicidin is a type of antimicrobial peptide.

A 2013 study showed that there are even microbes in the subepidermal fat layers and not only on the skin surface. A healthy skin microflora protects from infection in a manner similar to healthy gut microflora – by overpopulating overgrowth of disease-causing microorganisms. Moreover, the skin microflorae prefer a slightly acidic pH (about 4-4.5) which prevents the growth of pathogenic microorganisms.

Between the skin’s immune system and microflora

The skin’s immune system and skin microflorae regularly communicate with each other and control inflammation. When the microflorae are imbalanced, the skin’s immune system may release antimicrobial peptides, like cathelicidin, to help balance things out. Likewise, the skin microflorae may prevent the skin’s immune system from releasing inflammatory compounds.

Research done on mice in 2017 suggested that during early infancy, microflorae present on the skin induce “tolerance” in the infants. This may decrease the incidence of autoimmune diseases in adulthood.

Exposure to antibiotics during infancy that damages the skin microflorae may disrupt the induction of tolerance and allow the development of autoimmune diseases later in life. Some studies point to a correlation between the health of the skin microflorae and the maintenance of overall immunity.

The relationship between skin health and skin flora

What are the characteristics of good skin?

Beautiful skin has the following qualities:

1. Even tone or colour

Consistent colour or an even tone is the first sign of a healthy and youthful skin. From a young age, the skin is capable of regulating its pigmentation naturally; thereby resulting in a healthy-looking and uniform tone. However, the only exception to this is freckles, which are due to genetics.

2. Even and smooth texture

Another feature of beautiful skin is an even, smooth texture that is devoid of bumps and other common skin problems such as acne, whiteheads, blackheads, scars and wrinkles.

3. Hydration

Keeping the skin moist and hydrated is essential to ward off fine lines and wrinkles. Dry skin may lead to scaling and flaking.

4. Normal sensations

A healthy skin should not make its presence felt. As a matter of fact, there should not be any uncomfortable or unusual sensations, such as tightness and dryness after washing the face.  Some other abnormal skin sensations also include itching, stinging, burning, and pulling.

What are the characteristics of bad skin?

Some of the signs that the skin is in poor health are:

1. Uneven texture and/or blotchiness

An unhealthy skin has a blotchy, uneven texture. Light or dark coloured or red spots or circles may develop under the eyes.

2. Acne

The development of acne indicates that the skin is unhealthy. Acne may occur due to excessive oil production and clogging of the skin pores by dead skin cells.

3. Scaly, flaky skin

Dryness due to dehydration may result in scaly, flaky skin.

4. Abnormal sensations

Abnormal skin sensations may develop such as itching, burning, stinging, pulling, or tightness.

How is your skin flora able to maintain good skin?

The skin surface contains millions of microorganisms in the form of bacteria, fungi and viruses. In the same way that good bacteria present in our gastrointestinal tract (gut) have an impact on our general health, microbes present on the skin have an impact on the way our skin feels and looks. They also impact the skin’s ability to form a barrier between the body and the outside environment.

According to Toral Patel, M.D., a dermatologist based in Chicago, skin microflorae are vital for maintaining not only the health of the skin but also our overall health. Healthy skin microflorae can protect against skin infections by preventing the overgrowth of disease-causing microorganisms. Skin microflorae are also able to fight against environmental and external factors.

The skin flora is able to maintain skin health by doing the following:

  • Helping in dampening inflammation
  • Promoting wound healing
  • Acting as a physical barrier to environmental toxins and some allergens
  • Limiting exposure to UV radiation and allergens
  • Minimizing oxidative damage caused by free radicals
  • Keeping the skin moist and plump

Evidence exists that balanced skin microflora may be effective in fighting against certain skin cancers.

What are the factors affecting the wellbeing and quantity of skin flora?

The factors that affect the well-being of skin flora include:

Cosmetic use

Ingredients in makeup affect the skin’s surface and are absorbed into the skin. They may thus lead to subtle changes that can have a negative impact over time. For instance, certain common ingredients present in eyeshadows that are harmful to the skin microflorae are aluminium powder, coal tar, bismuth oxychloride, formaldehyde, parabens, nanoparticles, talc and thimerosal. If one uses these products on a daily basis, these ingredients can play a significant role in altering the natural skin florae.

Products for personal care

Moisturizers and lotions might harm the skin, especially if applied to almost every part of the body. Certain ingredients present in these creams play a significant role in altering the microflorae of the skin. Some of them can even cause endocrine disorders.

BHA (Butylated Hydroxyanisole), fragrances, DMDM Hydantoin, Triethanolamine and Retinyl Palmitate are a few common ingredients.

Antiperspirant is another product that is potentially harmful and is commonly used. The active ingredient in antiperspirants is aluminium, which kills the bacteria residing on the underarms and temporarily stops the production of sweat by the sweat glands. There are potential links between antiperspirant use and breast cancer but no solid evidence exists to prove them.

Anti-bacterial soaps

Most people practice basic hygiene and hand washing without giving it much thought. However, what you should pay attention to is the kind of soap you are using. Anti-bacterial and anti-microbial soaps destroy not only harmful bacteria but also the good ones.

Bacteria, on exposure to triclosan, (an ingredient that is present in the majority of antibacterial hand cleansers) undergo genetic mutation. This mutation makes bacteria resistant to these compounds. Gradually they may become tolerant to certain antibiotics also.

Food sensitivities

Dairy and gluten are linked to skin diseases such as psoriasis and eczema. Healing the gut promotes overall health including skin health.

Host factors

Host factors such as age, sex and location play a huge role in the diversity of skin microflora.

Environmental factors

Environmental factors that are specific to a person such as choice of clothing, occupation and antibiotic use may modulate how the microflorae colonize their skin. Cosmetics, hygienic products, moisturizers and soaps are also factors that contribute to variations in skin microflorae.

Skin pH

According to a study published in the International Journal of Cosmetic Science, the natural pH of the skin surface is on average below 5 (4-4.5), which keeps the resident microflorae attached to the surface of the skin. The study also demonstrated that an alkaline pH (8-9) promotes the dispersal of microflorae from the skin.

Keeping skin flora healthy & alive

What can we do to maintain the wellbeing of our skin flora?

Given that skin microflorae play such a vital role in the maintenance of our appearance and health, it’s important to take appropriate steps to their health.

You can do the following to maintain a healthy skin microbiome:

Get out as much as possible

Spend some time outside of the house regularly. The ideal situation would be where you get dirty or are around animals. However, even a walk in the park may expose you to new kinds of microbes which may transfer to the skin and diversify or replenish your microbiome.

Relax often

Your body is not able to tolerate prolonged stress, and your skin is not an exception. Do things to manage stress so that your skin microorganisms can flourish. Some great ways to reduce stress include starting a gratitude or meditation practice, avoiding foods which tend to raise stress levels such as those that contain sugar or caffeine, practising yoga and limiting screen time.

Embrace your own skin

People usually get into their beauty and health routines pretty early in life, implying that they may not have the knowledge of whether they are right for the skin or not. Give your skin a break from the routine facial regimen you normally undertake. Experience how your skin feels without a multitude of products on it.

Clean out your cosmetic cabinet

Get rid of all beauty and cosmetic products which contain ingredients that may have the potential to deplete your skin’s microflorae. It’s best to avoid any products that read “antimicrobial” or “antibacterial” on their label and also to avoid products that contain ingredients including mineral oil, petroleum and its byproducts, parabens and propylene glycol. Even so-called “natural” products may contain certain unwanted ingredients.

Be sure to read their labels carefully.

Give your skin microflorae a boost, both inside and outside

You may apply various things to your skin to change its looks temporarily, but for permanent, natural beauty and health you must go deep inside. Supporting the gut microbes is the best area, to begin with. Ensure you take a high-quality probiotic daily, drink plenty of water, eat lots of prebiotic-rich, organic foods, exercise regularly and spend time outside.

Moreover, since the microflorae of your skin are so vital to the radiant glow on your face, you may want to give them additional support by using skincare products enhanced with probiotics. You can either go for a premium probiotic-containing skincare regimen or get a yummy yoghurt facial. You may also apply a powdered probiotic mixed with shea butter or coconut oil to your skin.

Probiotics may help to protect your skin from environmental toxins when applied directly to the skin.  Besides soothing temporary skin inflammation, they also help in bringing back the balance of your skin’s microbiome.

Minimize the use of soaps and hand sanitizers

Don’t use antibacterial soap on your skin. Try natural, non-toxic cleansers and moisturizers instead.

Exercise regularly and get sweaty

If you are eating a good diet, the sweat produced during exercise will act as food for your skin’s microflorae. Sweat acts in a similar way to how prebiotics works for gut bacteria. You can also get sweaty by spending some time in a sauna.

What kind of diet will maintain the wellbeing of our skin flora?

Eat clean foods high in fibre as they are rich in prebiotics

Prebiotics nourish the skin microflorae and help them to grow. Examples of such foods include asparagus, garlic, Jerusalem artichokes, soybeans and oats. By eating a diet high in prebiotics, you encourage a diversity of microbes and promote the growth of healthy skin microflorae.

Eat foods rich in probiotics every day

Though no recommended daily amount exists for probiotics, according to health experts, we should consume live bacterial cultures ranging from 1 billion-10 billion (measured in CFU or colony forming units) every day. Get a minimum of one serving of probiotic and prebiotic rich food per day.

Take probiotic supplements

Additionally, you may supplement your probiotic-rich diet with supplements that can promote and maintain the health of both skin and gut microflorae.

Eat a healthy diet and stay adequately hydrated

Eat a well-balanced diet that consists of good fats, carbohydrates, proteins and colourful vegetables. Drink lots of water to stay adequately hydrated. Avoid extra sugar and processed foods. Take organic food as much as you can.

What kind of skincare product ingredients will negatively impact our skin flora?

The ingredients in cosmetic products that may negatively impact the skin florae include aluminium powder, coal tar, bismuth oxychloride, formaldehyde, parabens, nanoparticles, talc, mineral oil, propylene glycol and thimerosal.

The ingredient that is present in antibacterial hand cleansers that negatively impacts skin microflorae is triclosan.

A study published in the International Journal of Current Pharmaceutical Research mentioned that a synthetic cosmetic contains seven ingredients in the form of water, preservatives, emulsifiers, colours, thickeners, stabilizers and fragrances. The study states that preservatives may remain active on the skin for a long time and they may alter the resident microflorae with continued use.

The study stated that people use deodorants to reduce body odour. Most deodorants have antibacterial ingredients that act against gram-positive bacteria. However, they may shift the normal florae to gram-negative bacteria and cause infections.

Can skin microflora cause harm to us?

Microflorae present on the skin can result in numerous non-infectious and infectious skin conditions that affect the hair follicles, epidermis, subcutis and dermis.

While commensals do not cause any harm in most individuals, they may result in minor diseases in some people or even serious disease in others. The below-mentioned factors tend to turn skin microflorae into pathogens:

  • A breach in the physical skin barrier as a result of injury, skin disease (for instance, dermatitis) or an invasive medical device (for instance, a central venous line)
  • Medicine to suppress the immune system
  • Suppression of the immune system due to HIV, infection or cancer
  • Age (both very old or very young age)
  • Genetic factors of an individual

Non-infectious medical conditions associated with skin microflora

Examples of such conditions are:

  • Demodex mites are associated with rosacea
  • Proprione bacterium acne is associated with acne
  • S. epidermidis is associated with miliaria
  • Mixed flora associated with hidradenitis suppurativa
  • Skin Infections

Skin infections may be due to:

  • Bacteria
  •  Fungi
  • Viruses

Skin diseases from various skin flora

Understanding coagulase-negative staphylococci and diseases caused by It

Our skin forms the initial barrier between our body and the outside world.  A variety of microorganisms colonize our skin because of this. A minimum of 47 types of coagulase-negative staphylococci is just some of them.

These are Gram-positive, aerobic bacteria, and they differ from Staphylococcus aureus bacteria, a closely related species, in their inability to produce Coagulase (an enzyme which converts fibrinogen into fibrin, promoting the formation of a thrombus). Coagulase-negative staphylococci were first discovered by the scientists Alexander Ogston and Louis Pasteur in the 1880s.

They are an important constituent of the normal skin microflorae.  Naturally, mucous membranes of children and adults contain them. Staphylococci prefer oily or moist sites of the body and are present in the gluteal, inguinal and axillary regions along with the conjunctiva and anterior nares.

Common species of coagulase-negative staphylococcus

  • S. epidermidis occurs usually in the perineum, axilla, groin, anterior nares, and conjunctiva and toe webs.
  • Usually in the pubic and axillary areas with a high number of apocrine glands, S. hominis and S. haemolyticus thrives in these areas.
  • S. capitis usually occurs surrounding the sebaceous glands present on the scalp and forehead after puberty.
  • S. lugdunensis is present in the pelvic, perineal and axillary regions, lower extremities and groin.
  • Around 10 to 24 strains of the group S. epidermidis are present on the skin of a normal healthy adult.
  • More than 50% of staphylococci bacteria isolated from the skin of humans are S. epidermidis. In brief, they account for more than 75% of Coagulase-negative staphylococci isolated in all of the clinical specimens.
  • Collectively, S. haemolyticus and S. epidermidis cause the majority of premature infections in neonates and foreign body infections as a result of Coagulase-negative staphylococci.

Skin conditions associated with coagulase-negative staphylococci

Miliaria

S. epidermidis bacteria causes miliaria. In this condition, there is occlusion of sweat ducts leading to a retention of sweat in the eccrine glands. In skin biopsies, it is demonstratedthat PAS (periodic acid-Schiff) positive material blocks the upper ducts of the eccrine glands. Usually, miliaria is associated with:

  • Commensal bacterial overgrowth, particularly of Coagulase-negative staphylococci
  • Strains of S. epidermidis which produce EPS (extracellular polysaccharide substances) those are PAS-positive
  • An occlusive environment such as the wearing of occlusive dressings and increased temperature leading to thermal stimulation

There is no association of miliaria with S. epidermidis strains that do not produce EPS or other types of Coagulase staphylococci (for instance, S. hominis and S. haemolyticus). Up to 60% of strains of S. epidermidis present on the back and forehead produce EPS.

Atopic dermatitis

According to a study published in the journal JAMA Dermatology, Coagulase-negative staphylococci bacteria are thought to be implicated in a theory referred to as the double-hit phenomenon, which is used to describe the causation of atopic dermatitis. The combination of effects of an environmental trigger and an abnormal FLG gene may result in the abnormal skin surface in people with atopic dermatitis. The abnormal environmental trigger can be miliaria (subclinical) as researchers have found PAS-positive substance in the eccrine glands of people suffering from atopic dermatitis.

Strains of S. epidermidis may produce the PAS-positive substance.  Instead of producing the usual lesion of miliaria, in people with the abnormal gene, occlusion of the eccrine glands may cause a flare-up of atopic dermatitis. This occurs by activation of the innate immune system. In this study, among the skin samples of patients suffering from atopic dermatitis, 42% had S. aureus, 20% had S. epidermidis and all had EPS.

Who is prone to getting coagulase-negative staphylococcal bacterial infections?

To begin with, Coagulase-negative staphylococci bacteria rarely produce disease when the skin is intact, despite being present abundantly on the skin. The major risk factor for infection with Coagulase-negative staphylococci is a medical implant in the body. However, the microorganism can colonize and proliferate on this and may also enter the systemic circulation.

Factors that increase the risk of getting Coagulase-negative staphylococcal bacterial infection include:

  • Pacemakers, prosthetic valves of the heart, cardiac stents, prosthetic joints and defibrillators
  • Systemic therapy to suppress the immune system (immunosuppressive therapy)
  • Intravascular devices including peripherally inserted arterial lines and central venous catheters. They are the cause of up to 40% of nosocomial infections of the bloodstream.
  • Orthopaedic implants – a history of joint surgery or prolonged surgery increases risk. There is also a risk of infection during surgery for an implant
  • Premature birth, very low birthweight (less than 1500 g) and the use of central or umbilical catheters in infants (this accounts for at least 31% of all neonatal infections occurring in intensive care units in the USA).

Signs and symptoms of coagulase-negative staphylococcal bacterial infections

Clinical symptoms and signs of hypotension, leukocytosis (increased white blood cells) and fever help in differentiating between true infection from Coagulase-negative staphylococci and contamination from the bacteria.

Identification of coagulase-negative staphylococci and diagnosis of infection

  • Cultures of clinically obtained specimens are made in an enrichment broth and blood agar plates.
  • Identification is done by examining the morphology and antibiotic susceptibility.
  • To identify specific species of Coagulase-negative staphylococci, sequencing of the whole genome and MLST (multi-locus sequence typing) of housekeeping genes is done.

How coagulase-negative staphylococci cause systemic infections

Coagulase-negative staphylococci enter via breached surfaces of the skin, usually during medical procedures. The main mechanism of causing systemic infection is the capability of the microorganism to make biofilms on the outside of implanted medical devices, where they replicate and then disseminate into the bloodstream.

Treatment of infection with coagulase-negative staphylococcal bacteria

Consider the following points when treating infection with Coagulase-negative staphylococcal bacteria:

  • The area of infection
  • The immune status of the host
  • Presence of any medical equipment in the body of the host

Ultimately, the focus of treatment is to provide appropriate systemic antibiotic therapy and to remove the implant that has caused the infection.

According to estimates, 90% of infections have developed a resistance to penicillin. The drug of choice is vancomycin. Linezolid, daptomycin, clindamycin, tedizolid, dalbavancin and tedizolid are newer antibiotics that treat Coagulase-negative staphylococcal bacterial infections. For infections that are deep-seated, the physician may add rifampicin or gentamicin.

The time taken to treat the infection depends on the area where the infection has developed.

Prognosis of infection with coagulase-negative staphylococcal bacteria

Infection with Coagulase-negative staphylococcal bacteria is a serious condition that causes significant mortality and morbidity. The septic shock rate is 22% and the mortality rate is 37%. According to estimates, 50% of deaths due to septic shock is due to systemic infection with Coagulase-negative staphylococcal bacteria.

Endocarditis of prosthetic valves due to Coagulase-negative staphylococci has a mortality rate of 24% to 36%.

Although infections in neonates due to Coagulase-negative staphylococci have a relatively low mortality rate of 0.3 to 1.6%, these infections cause a prolonged stay at hospitals and high morbidity.

Infections of prosthetic grafts have a mortality rate of 17% and a morbidity rate of 40%, particularly from amputation.

Diseases caused by corynebacterium

Corynebacterium is a small Gram-positive coccus that is present as part of the skin’s microflorae. It is usually a commensal microorganism. However, under some circumstances, it may cause certain skin problems.

The various skin diseases that may be caused by Corynebacterium are as follows:

Pitted keratolysis

Pitted keratolysis results in the occurrence of smelly feet and its cause is corynebacteria. It occurs in association with occlusive footwear and hyperhidrosis. Normally, either the heel of the foot or the front part of the foot becomes white. The foot also develops punched out pits in clusters, which become more obvious on wet skin.

Treatment of pitted keratolysis

Treat it with either topical antibiotic like fusidic acid (in cream form) or an oral antibiotic like erythromycin.

Keep the feet dry or it will recur quickly.  Additionally, physicians recommend the following points to prevent recurrence of the condition:

  • Avoid wearing boots for long durations. Wear them for very short periods only.
  • Wear socks that are able to absorb sweat effectively; for instance, wool and/or cotton socks.
  • Wear open-toed sandals when possible.
  • Wash your feet using antibacterial cleanser or soap twice a day.
  • Apply antiperspirant to your feet a minimum of twice a day.
  • Do not wear the same shoes consecutively for two days –  dry them in between.
  • Avoid sharing towels or footwear with other people.

Erythrasma

Corynebacterium minutissimum causes this infection. Usually, it is asymptomatic, and it occurs in skin flexures, such as in the groin and axillary areas. It tends to occur more frequently in people suffering from diabetes mellitus.

It manifests as an area of brown or pink dry skin that enlarges slowly. Generally, erythrasma is diagnosed by collecting a scraping and getting a culture and microscopic examination done.

Treatment of erythrasma

Whitfield’s ointment is a good antiseptic for treating Erythrasma. Essentially, topical antibiotics like clindamycin solution or fucidic acid cream also work. Oral antibiotics like tetracycline and erythromycin may help to treat extensive infection, and there is usually a prompt response. Together with antibacterial soap, this can prevent a recurrence.

Trichomycosis axillaris

Trichomycosis axillaris occurs due to the multiplication of Corynebacterium (usually Corynebacterium tenius) on the hair present in the underarm. Pubic hair infection is called trichomycosis pubis. Granular nodules of a yellow colour (less often of a red or black colour) envelop the hair shaft. Over time, the sweat may become discoloured and stain the clothes.

Treatment of trichomycosis axillaris

The easiest treatment of Trichomycosis axillaris is to shave the affected site. Using benzoyl peroxide in gel form, antiperspirants and antibacterial washes may also help.

Diseases caused by malasezzia

Malassezia is a group of fungi belonging to the genus Malassezia that contains many different species. These species of fungi are namely M. dermatis, furfur, equi, globosa, pachydermatis, obtusa, restricta, sympodialis, slooffiae, and ovalis (or Pityrosporum ovale).

Skin conditions that are aggravated or caused by a Malassezia infection are:

Pityriasis versicolor

Malassezia sympodialis, furfur and globosa can cause a common fungal infection that looks like discoloured flaky patches on the back and chest. The patches are generally asymptomatic, but they may be mildly itchy in some people. This infection tends to occur more frequently in young adults and is more common in males than females. It also more commonly occurs in hot, humid weather than in dry, cool weather. Also, people who sweat heavily are more prone to it.

Generally, the diagnosis is made clinically. It may also be diagnosed using the Wood lamp examination in which a yellow-green fluorescence is observed in the affected areas.

Topic antifungals can treat the fungal infection, with products such as topical azole shampoo/cream (ketoconazole, econazole), terbinafine gel, selenium sulfide, propylene glycol solution, ciclopirox solution/cream and sodium thiosulphate solution. It is advisable to apply the medicine thoroughly to all affected sites before going to bed. Extensive Pityriasis versicolor may require oral antifungals such as fluconazole and itraconazole.

Malassezia folliculitis

This is a hair follicle infection and inflammation caused by the Malassezia fungus. Usually, it occurs in young adult and adolescent males who live in hot, humid climates. Other factors that increase the risk of developing the condition are a high sebum production, excessive sweating, use of antibiotics, occlusion from sunscreens and emollients, uses of oral steroids including prednisone and immunosuppression.

The disease is characterized by the presence of small, itchy, uniform pustules and papules on the chin, neck, forehead, and the extensor part of the arms and trunk. It is usually diagnosed on clinical examination.

Typically, the treatment for this involves oral antifungals as they are more effective than topical agents. Fluconazole is the drug of choice. Any factors that predispose to developing the condition should be addressed in the beginning as the condition has a high recurrence rate even after successful treatment.

Seborrheic dermatitis, sebopsoriasis, dandruff and scalp or facial psoriasis

This is a common, chronic form of dermatitis which mainly affects areas of the face, trunk and scalp that are rich in sebaceous glands. There are the adult and infantile types of seborrheic dermatitis, also known as seborrheic eczema.

This condition is most often caused by a proliferation of M. globosa and restricta. The metabolites of the fungus such as fatty acids, indole-3-carbaldehyde, and malssezin may produce an inflammatory reaction.

Dandruff is a type of seborrheic dermatitis that is not characterized by inflammation. It presents as scaly patches that resemble bran on the areas of the scalp containing hair.

Infantile seborrheic eczema occurs in babies below the age of three years. Usually, it gets better by six months to one year of age.

Adult seborrheic eczema tends to start in adolescence and is more prevalent in the elderly and in young adults. Also, it occurs more commonly in males than females.

Factors associated with severe adult seborrheic eczema
  • A family member with psoriasis or a tendency to have seborrheic dermatitis in the family.
  • Oily skin
  • Immunosuppression in people who have undergone an organ transplant, have HIV or lymphoma.
  • Psychiatric and neurological diseases: Parkinson disease, depression, tardive dyskinesia, epilepsy, injury to spinal cord, congenital disorders including Down syndrome and facial nerve palsy.
  • Undergoing psoriasis treatment with ultraviolet A therapy (PUVA) and psoralen.
  • Stressful events and lack of proper sleep.

Infantile seborrheic eczema results in cradle cap (greasy, diffuse scaling present on the scalp). The rash can spread to the groin and armpits. The patches are salmon-pink in colour and may peel or flake. However, the rash is non-itchy and does not disturb the baby.

Adult seborrheic eczema affects the scalp, face (areas behind ears, around the nose, eyebrows) and upper body. The rash typically flares in winter and improves in summer after exposure to the sun, however, there is usually minimal itchiness. There may be localized patches of scale on the scalp. Blepharitis may occur which is characterized by red and scaly margins of the eyelids. Also, rash may develop in the armpits, groin folds, genital creases and under the breasts.

Clinical appearance decides diagnosis.

Treatment may involve several of the options below:
  • Scales are removed by keratolytics.  Lactic acid, propylene glycol, urea and salicylic acid are effective.
  •  Malassezia is decreased by topical antifungals. Ciclopirox cream and/or shampoo, ketoconazole are effective.
  • Mild corticosteroids (topical) are prescribed for a duration of one to three weeks to decrease inflammation when there is an acute flare-up.
  • Calcineurin inhibitors (topical) such as tacrolimus ointment or pimecrolimus cream may be indicated as alternatives to topical corticosteroids as they have fewer side effects.
  • Resistant adult cases warrant the use of oral tetracycline antibiotics, phototherapy or itraconazole.
Treatment of the scalp
  • Medicated shampoos that contain ketoconazole, selenium sulfide, ciclopirox, coal tar, and salicylic acid and zinc pyrithione should be used two times a week for a minimum of one month.
  • Steroids should be applied for a few days to the scalp to reduce itching.
  • Calcineurin inhibitors including tacrolimus may be used in place of steroids.
  • Cream containing coal tar can be applied to areas that have scales and then removed after several hours by shampooing.
  •  Combination therapy may be recommended.
Treatment of face, chest, back and ears
  • Clean the affected area thoroughly two times daily with a cleanser that does not contain soap.
  • Apply ciclopirox or ketoconazole cream once in a day for two to four weeks, repeating it as required.
  • Hydrocortisone cream may be applied up to two times in a day for one to two weeks.
  • Calcineurin inhibitors may be used, including tacrolimus ointment or pimecrolimus cream in place of steroids.
  • Various herbal remedies may be used; however, their efficiency in treating the condition is uncertain.
Treatment in infants
  • It is recommended to wash the scalp using aqueous cream or baby shampoo followed by brushing gently to clear scales.
  • White petrolatum has been found to be useful.
  • Depending on the severity of the rash, the physician may prescribe topical antifungal agents.

Possibly certain cases of reticulated and confluent papillomatosis

A pigmented eruption pigmented occurs mainly on the back, neck and chest of adolescent females.

Neonatal cephalic pustulosis

This is a pustule-like eruption that occurs in young babies and has an appearance similar to infantile acne.

Certain cases of atopic dermatitis occurring on the face: Invasive pityrosporosis

This is rare but occurs in persons who are immunodeficient.

Factors that predispose to the proliferation of malassezia

Various species of Malassezia colonize the skin without producing any harm under normal circumstances. However, in some individuals, the fungi suppress the body’s immune response, which results in its proliferation leading to a skin disease. A small inflammatory response is associated with an overgrowth of Malassezia. The irritating metabolites produced by the fungus causing this.

Factors that predispose to skin diseases due to Malassezia are:

  • High humidity
  • Excessive sweating-therefore, Pityriasis versicolor is prevalent in tropical regions
  • Oily skin-therefore, it is present mainly on the face, upper trunk and scalp

Malassezia produces chemicals which reduce skin pigment, resulting in whitish patches. The pigments include pityriacitrin, malassezin and azelaic acid.

Malassezia may produce fluorescence when exposed to ultraviolet light; for instance, Wood’s lamp, due to the presence of the chemical pityrialactone.

Diseases caused by demodex

Demodex are tiny mites which reside in hair follicles. In human beings, Demodex is present on the skin of the face, particularly the cheeks, forehead, sides of nose, external ear canals and eyelashes. Sometimes it leads to a condition referred to as demodicosis.

Two types of Demodex mites principally cause an infestation in humans,

  • Demodex folliculorum is present in small hair follicles, especially the eyelashes. In both the adult and immature stages, the mite feeds on skin cells.
  • Demodex brevis is present in oil glands which are attached to small hair follicles and the mite feeds on the cells of the gland.

The length of D. folliculorum is 0.3-0.4 mm, whereas the length of D. brevis is 0.16-0.2 mm. They are not visible to the naked eye; however, they are clearly visible under a microscope. The mite has eight legs and it moves at the rate of eight to 16 mm/hour. Usually, the mite moves during night time as due to bright light it recedes back into the follicle.

Demodex mites are normally present in adults and older children (above the age of 5 years). They are rarely present in children below the age of 5 years.

Who gets demodicosis?

Usually, demodicosis occurs in adults and in immunodeficient persons such as those with HIV infection.

Signs and symptoms of demodicosis

Demodicosis causes non-specific signs and symptoms on the skin of the face, including:

  • Redness
  • Follicular scales
  • Skin itching
  • Skin sensitivity
  • Macules, eczema, papules, pigmentation and folliculitis

Patients suffering from demodicosis may develop irritation of the eyes, scaling and itching of eyelids (eyelid dermatitis or blepharitis). Additionally, the patient may develop symptoms of lid thickening, loss of eyelashes (madarosis), decreased vision and inflammation of the conjunctiva.

The conditions mentioned below increase the number of Demodex mites:

  • Demodex folliculorum- Skin becomes rough due to the occurrence of scales within the hair follicles
  • Demodectic frost of ear- Gritty, frosted follicular scaling occurs of the helix and earlobe
  • Rosacea
  • Certain cases of perioral dermatitis (may also affect periauricular or periorbital sites)
  • Otitis externa (also referred to as auricular demodex)
  • Demodex abscess

Diagnosis of demodex

Skin biopsies examined under a microscope will show Demodex. Ordinarily, this is done with samples of the skin surface.  When a large number of Demodex mites are present (greater than 5/cm2), doctors can diagnose Demodex.

Demodicosis treatment

Demodex live only in the hair follicles of human beings. If they are not allowed to proliferate excessively, no problems are created. Strategies to treat and prevent demodicosis at home include:

  • Shampooing eyelashes and hair with mild shampoo every day.
  • Cleaning your face with a mild cleanser (non-soap) two times a day.
  • Avoid oil-based cleansers and greasy makeup.
  • Exfoliating your skin periodically so as to shed dead skin cells.

Ultimately, the aim when using acaricides (substances to kill mites) for treatment is to reduce the excessive growth of mites and to cure the signs and symptoms of demodicosis. The various options are:

  • Permethrin cream
  • Solution of benzyl benzoate
  • Sulfur ointment
  • Selenium sulfide available as a wash
  • Crotamiton cream
  • Metronidazole gel
  • Ivermectin cream
  • Salicylic acid cream

Severe cases warrant oral ivermectin treatment.

Periorbital demodicosis

Spread the ointment at the base of eyelashes during the night so as to trap mites when they get out of the follicle. Alternatively,  first scrub your lashes with a baby shampoo, after which apply macadamia nut essential oil or tea tree essential oil to the area to kill the eggs.

References

https://www.dermnetnz.org/cme/bacterial-infections/corynebacteria/
https://www.dermnetnz.org/topics/microorganisms-found-on-the-skin/
https://www.dermnetnz.org/topics/coagulase-negative-staphylococci/
https://www.dermnetnz.org/topics/pityriasis-versicolor/
https://www.dermnetnz.org/topics/malassezia-folliculitis/
https://www.dermnetnz.org/topics/seborrhoeic-dermatitis/
https://www.dermnetnz.org/topics/malassezia-infections/
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