Skin flora, normal

A distinction is made between resident flora (site flora: germs that colonize the skin permanently) and transient flora (approach flora: germs that can only be detected on the skin for a short time, e.g. Staphylococcus aureus, Streptococcus pyogenes). The resident flora consists mainly of bacteria and yeasts.

• Bacteria:
  • Aerobic gram-positive cocci: staphylococci, e.g. S. epidermidis, S. hominis, various micrococci species.
  • Anaerobic coryneform bacteria: V.a. Propionibacterium acnes.
  • Aerobic coryneform bacteria: e.g. Corynebacterium minutissimum, C. tenuis and others; Brevibacteria.
• Yeasts: Pityrosporon ovale (Malassezia furfur).

There are large inter- and intraindividual differences with regard to the skin flora: the composition depends on age (in children streptococci are more frequent, in adults coryneform bacteria), skin moisture (higher bacterial density on moist skin, increased staphylococci), sebum production(Pityrosporon ovale and Propionibacterium acnes in areas rich in sebaceous glands). In the axilla, 2 types of flora are distinguished:

• dominance of coryneform bacteria
• dominance of cocci.

In the case of dominance of coryneform bacteria , erythrasma, trichobacteriosis axillaris and stronger axillary odour occur more frequently than in the case of dominance of cocci.

1. Kim JE et al (2019) Microbiome of the Skin and Gut in Atopic Dermatitis (AD): Understanding the Pathophysiology and Finding Novel Management Strategies. J Clin Med 8:444.
2. Korting HC et al (1988) Microbial flora and odor of the healthy human skin. Dermatologist 39: 564-568
3. Larson EL et al (2003) Microbial flora of hands of homemakers. Am J Infect Control 31: 72-79