Antagonism within populations of micro-organisms from normal human skin

Abstract

SUMMARY.The skin flora of 20 normal subjects was sampled from 7-cm2 sites on the volar forearm, forehead and ball of the foot. Interactions between all aerobic and anaerobic strains isolated from the same site were examined by a deferred-antagonism technique. Seventeen subjects possessed inhibitory strains on at least one skin site. Of the Micrococcaceae tested, 20.6% were inhibitory. Of the aerobic diphtheroids, more strains were sensitive (1 9.2%) than inhibitory (5-1 %). Inhibitory Micrococcaceae and aerobic diphtheroids revealed intergeneric and intrageneric inhibition. Antagonistic propionibacteria were found (7.4%) but no sensitive strains. Several Micrococcaceae were specifically antagonistic towards only one strain isolated from the same skin site; no sensitive strains from other skin sites or other subjects were found. Quantitative sampling showed that only 17.5% of the inhibitory strains clearly dominated their skin sites numerically.

Skin microbiota: Microbial community structure and its potential association with health and disease

“…For many decades, researchers have been interested in defining the microbial inhabitants of human skin, focusing on descriptive features such as their association with infection (McBride et al, 1977), their stability over time (Evans, 1975), and their interactions with other microbes (Wright and Terry, 1981). Currently, our understanding of the human microbiota is undergoing a dramatic reassessment.…”

Role of reduced sulfur compounds in nutrition of Propionibacterium acnes

“…Since in any ecosystem the environment determines to a great extent the types of organisms that will develop, those organisms that possess the physiological properties and biochemical capabilities to deal with these ecological forces will survive and proliferate to the exclusion of others. Among the selective forces in skin limiting the number of species in the resident flora are a pH range of 5 to 6 (10); the presence offatty acids produced by the action of microorganisms on sebum (14), some of which are toxic to other organisms (11); the lack of moisture, which restricts the development of gram-negative organisms (10); and various inhibitory substances produced by the resident organisms (2,16,17). In addition, sebaceous follicles provide an anaerobic environment for P. acnes (5).…”