Microbiology of specialized skin: the vulva.

Human vulvar skin is an example of specialized skin. This is not only true for its gross and microscopic anatomy and physiology, but also for its microbiology. To the microbiologist, the vulva consists of several distinct ecotopes. These are defined by the physical factors, especially occlusion, nutrient factors, and by the close proximity to the vagina, the urethra, and the anus, which may result in contamination with the flora typical for those sites. Of the vulva ecotopes, only the labia majora have been seriously studied. The microbial flora of the labia majora is characterized by a high density of microorganisms, as is typical for occluded areas of the body, by the presence of organisms common for intertriginous skin such as gram-negative rods, and by the carriage of organisms unique for the vulva and probably related to urethral and vaginal flora such as the nonpathogenic neisseria, lactobacilli, and Gardnerella vaginalis. Finally, the labia majora skin is a preferred site of Staphylococcus aureus carriage that can be of clinical and epidemiological relevance.