Suppression of polymorphonuclear leukocyte chemotactic factor production in Propionibacterium acnes by subminimal inhibitory concentrations of tetracycline, ampicillin, minocycline, and erythromycin

Propionibacterium acnes is the cause of inflammation in acne vulgaris and has been shown to produce potent neutrophil chemoattractants. Different strain of P. acnes that were sensitive or resistant to ampicillin, erythromycin, minocycline, and tetracycline were grown in the presence of subminimal inhibitory concentrations of the drugs, and their culture supernatants were assayed for neutrophil chemotactic activity. The presence of subminimal inhibitory concentrations of ampicillin failed to affect chemotactic factor production by any of the strains. Subminimal inhibitory concentrations of tetracycline, minocycline, and erythromycin all produced decreased neutrophil chemotactic activity in P. acnes culture supernatants. This inhibition of chemotactic activity was most pronounced in strains of P. acnes which were susceptible to the drugs. The addition of antibiotics at appropriate concentrations to control supernatants failed to affect neutrophil migration. The results indicate that subminimal inhibitory concentrations of antibiotics are capable of reducing the inflammatory capacity of P. acnes.