Inhibitors produced by propionibacteria and their possible roles in the ecology of skin bacteria

Abstract

SynopsisHuman skin propionibacteria have been shown to produce,in vitro, a wide range of inhibitory substances including bacteriocins, bacteriolytic enzymes, bacteriophages and low molecular weight metabolites (e.g. ammonia, propionic acid). Some or all of these substances may play a role in the ecology of cutaneous populations of micro-organisms and may be involved in maintaining the balance of the normal flora. There is no evidence to suggest that they deter or exclude other transient bacteria including pathogens. Similarly, evidence in support of thein vivoproduction of growth inhibitors by propionibacteria with activity against other skin micro-organisms is lacking (except for bacteriophage and propionic acid) so that their potential role in controlling cutaneous populations must be interpreted with caution.