Diphtheroid osteomyelitis.

Isolates of either Corynebacterium diphtheriae or Propionibacterium acnes from osteomyelitis are not necessarily contaminants, as shown by the cases of three patients who had bone and joint infections in which these organisms were pathogenic (one in pure culture and two in mixed cultures). Previous operation or other factors that compromise host resistance create the setting for these opportunistic organisms. Penicillin with or without streptomycin is the treatment of choice, but if penicillin or streptomycin cannot be used then the cephalosporins, clindamycin, and erythromycin are acceptable alternatives (depending on susceptibility studies). In general, the prognosis is good.