[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
February 1971

Ecological Effects of Oral Antibiotics on the Microflora of Human Skin

Author Affiliations


From the Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia.

Arch Dermatol. 1971;103(2):148-153. doi:10.1001/archderm.1971.04000140034006

The capacity of orally administered antibiotics to alter the resident microbial flora of the skin was evaluated after three weeks of treatment with tetracyclines, penicillins, erythromycin, and a lincomycin derivative. An increase in the percentage of resistant organisms was the most sensitive indicator that an antibiotic had reached the surface; conversion from a dominantly diphtheroid to coccal flora was another evidence of substantial surface levels. It was concluded that this mainly happened as a result of holocrine excretion via epidermal or sebaceous cells. Tetracyclines and erythromycin were instances of the latter effect. Penicillins did not materially alter the microflora, except for a slight increase in resistant cells. Significant reductions in the density of Cornebacterium acnes on the forehead were produced by three of four tetracyclines and the lincomycin derivative.