Effect of hamster liver passage on the isoenzyme patterns of Entamoeba histolytica.

The effect of hamster liver passage on the isoenzyme patterns of isolates of Entamoeba histolytica was investigated. Three isolates, F, G and T were originally obtained from patients with acute amebic dysentery and another strain, C, was obtained from an asymptomatic carrier. All these strains were maintained for over two years in axenic culture. The isoenzyme pattern (zymodeme) of hexokinase (HK), phosphoglucomutase (PGM) and glucose phosphoisomerase (GPI) of these strains was found to belong to non-pathogenic group X, but the isoenzyme pattern of GPI resembled less pathogenic zymodeme XX and might be an intermediate type. Following inoculation of trophozoites into hamster livers and recovery after abscess formation, their isoenzyme pattern changed and revealed that they belonged to pathogenic type XIV. Liver passage caused an enhancement in amebic virulence as evidenced by their increased ability to destroy leukocytes. The results indicate that isoenzyme pattern is not a stable property of E. histolytica.