Inhibition of phagocytosis in vitro by obligate anaerobes.

A variety of species of obligate anaerobes have been shown to interfere with the phagocytosis and killing of Proteus mirabilis and other aerobic bacteria in vitro. Although all the obligate anaerobes examined showed this activity, the effect was greatest with strains of Bacteroides melaninogenicus and B. fragilis. In contrast, none of the 36 aerobes tested acted in this way. These observations suggest that the presence of obligate anaerobes may be fundamental to the pathogenesis of some types of infections.