Natural antibiosis among skin bacteria as a primary defence against infection.

Antibiotic-producing bacteria were present on the healthy intact skin of 77 of 340 people but predominated in only 38-9% of these. In contrast, antibiotic-producers which occurred in the lesions of 51 out of 263 dermatological patients predominated in 78-4%. The presence of inhibitory commensals in skin lesions was associated with a significantly low incidence of secondary infection both on admission and during hospital stay; there was, however, a small excess of Gram-negative infections on admission in skin lesions containing antibiotic producers. Among ninety surgical patients, also, the presence of inhibitory skin bacteria was associated with a relatively low rate of wound colonization by pathogenic bacteria. The ecological implications and practical applications of the findings are discussed.