Acidity of the skin: influence of external factors
Barrier of bacteria and maintenance of balance
Continuing the series of articles on skin pH, we will talk about how the acidity of the skin affects the lipid composition of the stratum corneum, its hydration, the barrier function of the skin, its microbiota, as well as how an acidic skin pH promotes an optimal microenvironment for resident bacteria and their enzyme activity.
The acidity of the skin surface affects many factors for the growth of resident flora and pathological microorganisms. An acidic pH is one of the main factors that make the skin less hospitable to bacteria.
A high density of bacteria is found in regions of the skin with a less acidic pH, such as genitofemoral areas, anal area, submammary folds, axillary folds.
Normal microflora also acts as a barrier and serves to prevent the invasion and growth of pathogenic bacteria. Healthy growth and maintenance of resident flora effectively prevents colonization by transient bacteria (E. coli, Pseudomonas, S. aureus, C. albicans). Skin antimicrobial protection includes mechanical rigidity of the stratum corneum, reduced moisture content, stratum corneum lipids, lysozyme, pH 5.
Skin flora also produces protein and lipid antibacterial components, so-called "bacteriocins", which are involved in bacterial competition for survival in this microenvironment. For example, the bacteriocin - Pep 5, produced by S. epidermidis, is partially active against other staphylococci, especially S. aureus.
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