The microbiome revolution

The human microbiota refers to all micro-organisms (bacteria, fungi, viruses) living in symbiosis with their human host. There are various microbiota, each present in different parts of the body in which an epithelium is in contact with the outside of the body: the digestive tract (stomach, intestines) the skin, the respiratory tract (mouth, pharynx, lungs) and the urogenital tract ⁽¹⁾. All these microbiota are of bacterial origin and are non-pathogenic.

The microbiome refers to the environment in which the microbiota evolves: pH, temperature, hormones, absence or presence of light…

There is therefore a cutaneous microbiota, also called skin flora, which refers to all the micro-organisms living on the surface of the skin and in its superficial layers, thus creating a complex ecosystem.

It consists of a relatively stable commensal flora, also called resident flora (Gram+ species with two main families: staphylococci and aerobic and anaerobic coryneform bacteria). These commensal bacteria are present in the epidermis, the sebaceous and sweat glands, the hair follicles, but also in deeper cutaneous sites such as the dermis and hypodermis ⁽²⁾.

It also consists of a transient flora composed of micro-organisms temporarily present on the skin ⁽³⁾. It varies according to the conditions of the environment (the most common are Staphylococcus aureus, Pseudomonas aeruginosa and certain species of Bacillus) ⁽⁴⁾. These micro-organisms are not pathogenic but they can become so if for example they are ingested, hence the need to wash hands frequently!

Resident or transient, the cutaneous microbiota varies quantitatively and qualitatively from one person to another according to age, gender, immune system and certain physicochemical factors such as humidity, pH and temperature.

The cutaneous microbiota is a fundamental element of the good health of the skin since it plays a role of defense against pathogenic bacteria. An imbalance of it can lead to skin disorders such as dermatitis, acne or psoriasis.

Cosmetic brands have seized the subject and now offer products that respect the balance of the cutaneous microbiota.

Emulium® Mellifera MB is a natural O/W emulsifier that allows the formulation of a wide range of textures suitable for all skin types and climates. It creates natural emulsions with white and luxurious appearance, while leaving a light and smooth afterfeel. Its moisturizing and anti-pollution properties, its capacity to visibly improve skin texture and its high tolerance even for sensitive and hyper reactive skin make Emulium® Mellifera an active emulsifier.

To go even further in understanding of a healthy skin, Gattefossé demonstrated that Emulium® Mellifera MB is microbiome-friendly, meaning that it maintains, even improves the balance of the cutaneous microbiota. 

The objective of this research was to study the effect of an emulsion formulated with 4% of Emulium® Mellifera MB on moisturization, barrier function and pH of the skin and understand its impact on cutaneous microbiota. Several evaluation techniques have been used:

• Self-assessment by the volunteers
• Satisfaction questionnaire
• Biometrological measures: corneometry, TEWL
• Questionnaire to understand what volunteers know about cutaneous microbiota
• Study of cutaneous microbiota by amplification and sequencing of ribosomal 16S DNA

Results showed an increase of moisturization, a reduction of TEWL reflecting a better barrier function and an improvement of the skin quality of volunteers.

More importantly, the study of cutaneous microbiota after application of an emulsion containing Emulium® Mellifera MB revealed that the taxonomic diversity and richness of the skin flora have been improved for 81% of volunteers. These taxonomic diversity and richness are directly linked to a healthy skin, able to defend itself against external aggressions.

References

⁽¹⁾ Di Domizio et al. (2016).  « Le microbiote cutané : le poids lourd sort de l’ombre ». Rev Med Suisse; 12 : 660-4

⁽²⁾ Nakatsuji T, et al. (2013) “The microbiome extends to subepidermal compartments of normal skin. Nat Commun” 2013;4:1431.

⁽³⁾ Mokni, M., & Abdelhak, S. (2014). « Flore cutanée, microbiote et microbiome », 1–4.

⁽⁴⁾ Dunyach-Remy, C., Sotto, A., & Lavigne, J.-P. (2015). Le microbiote cutané : étude de la diversité microbienne et de son rôle dans la pathogénicité. Revue Francophone Des Laboratoires, 2015(469), 51–58.