The epidemiology of Entamoeba histolytica in Mexico City. A pilot survey I.

Stocks of intestinal amoebae isolated from hospital patients in Mexico City and grown in monoxenic culture were compared among themselves and with those already described (SARGEAUNT & WILLIAMS, 1979), using the electrophoretic patterns of four enzymes: glucose phosphate isomerase (GPI), phosphoglucomutase (PGM), L-malate:NADP+ oxido-reductase (oxalacetate-decarboxylating) (ME) and hexokinase (HK). New isoenzyme groups (SARGEAUNT & WILLIAMS, 1979) of all the amoebae, including Entamoeba histolytica have been demonstrated. Amongst these have been found seven more groups of E. histolytica, two new groups of E. hartmanni, one new group of Dientamoeba fragilis and one new group of E. coli. Of the seven new groups of E. histolytica three are known to originate from patients with clinical amoebiasis whilst the remainder are from asymptomatic subjects. Only 11.2% of the 125 isolations were associated with clinical amoebiasis, and these are clearly distinguished from the isolations from asymptomatic patients by their electrophoretic isoenzyme pattern.