The Composition and Influencing Factors of Skin Microbes

The Composition and Influencing Factors of Skin Microbes

1. Composition of skin microbes

Skin microbes are important members of the skin ecosystem, and the flora on the skin surface can usually be divided into resident bacteria and transient bacteria. Resident bacteria are a group of microorganisms that colonize healthy skin, including Staphylococcus, Corynebacterium, Propionibacterium, Acinetobacter, Malassezia, Micrococcus, Enterobacter, and Klebsiella. Temporary bacteria refer to a class of microorganisms obtained through contact with the external environment, including Staphylococcus aureus, Streptococcus hemolyticus and Enterococcus, etc. They are the main pathogenic bacteria that cause skin infections. Bacteria are the predominant bacteria on the skin surface, and there are also fungi on the skin. From the phylum level, the new drama on the skin surface is mainly composed of four phyla, namely Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes. From the genus level, the bacteria on the skin surface are mainly Corynebacterium, Staphylococcus and Propionibacterium. These bacteria play a major role in maintaining skin health.

2. Factors affecting skin microecology

(1) Host factor

Such as age, gender, location, all have an effect on skin microbes.

(2) Skin appendages

Invaginations and appendages of the skin, including sweat glands (sweat and apocrine glands), sebaceous glands, and hair follicles, have their own unique flora.

(3) Topography of the skin surface.

Topographical changes of the skin surface are based on regional differences in skin anatomy. Culture-based methods study that different topographical areas support different microorganisms.

(4) Body parts

Molecular biological methods detect the concept of bacterial diversity, emphasizing that the skin microbiota is body site dependent. Bacterial colonization is dependent on the physiological site of the skin and is associated with a specific moist, dry, sebaceous microenvironment, etc.

(5) Time change

Molecular biological methods were used to study the temporal and spatial changes of skin microbiota, which were found to be related to the time and location of sampling.

(6) pH change

As early as 1929, Marchionini proved that the skin is acidic, thus establishing the concept that the skin has a “countercoat” that can inhibit the growth of microorganisms and protect the body from infection, which has been used in dermatological research to this day.

(7) Exogenous factors – the use of cosmetics

There are many exogenous factors that affect the skin microecology, such as temperature, humidity, air quality, cosmetics, etc. of the external environment. Among the many external factors, cosmetics are one of the important factors affecting the skin microecology in some parts of the human body due to the frequent contact of the skin with cosmetics.