Bacterial flora in intestinal amoebiasis.

Entamoeba histolytica was first cultured in vitro in 1925 (Boeck and Drbohlav, 1925) but has not yet been grown in the absence of living bacteria. Experimentally the dependence of E. histolytica on living bacteria in the intestine is well illustrated by the inability of E. histolytica to survive and invade the bowel wall of germ-free guinea-pigs (Phillips, Wolfe, Rees, Gordon, Wright, and Reyniers, 1955) and clinically by the observation that certain antibiotics halt acute amoebic dysentery by inhibiting the growth of intestinal bacteria (Elsdon-Dew, Armstrong, and Wilmot, 1952) but do not affect amoebic liver abscess (Wilmot, Armstrong, and Elsdon-Dew, 1952). The mean size of E. histolytica cultured from bacteria-free human amoebic liver abscess varies according to the bacterial parasites provided (Freedman and Elsdon-Dew, 1958). However, the role of bacteria in the pathogenicity of E. histolytica is obscure; bacteria probably attack the tissues of the host and reduce the resistance or supply essential factors for the growth of amoebae. In the literature, evidence is provided to show that bacteria are necessary for the growth of amoebae in the colon, yet there are no studies to the best of our knowledge to show whether or not any specific bacteria are associated with the growth of amoebae in the intestine.