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.