An Enriched, Egg Extract Medium for Recovering Viable Entamoeba Histolytica Trophozoites from Fecal Suspensions Kept at Room Temperature for Four Days

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  • Department of Health, Education and Welfare, Communicable Disease Center, Public Health Service, Atlanta, Georgia
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  1. 1.Balamuth's egg extract medium without liver, enriched with dextrose, Trypticase and sodium thioglycollate has been found to be superior to the original medium in ability to support Entamoeba histolytica in cultures with mixed bacteria.
  2. 2.Trophozoites of three strains of E. histolytica and of two strains of E. hartmanni were inoculated into the enriched medium plus antibiotics, a fecal suspension was added, and the tubes were stored at room temperature for up to 4 days. Upon incubation at 37°C, viable amebae were recovered from all tubes stored for 1 and 2 days, and from approximately 75% of those stored for 3 and 4 days.
  3. 3.In 2 field trials, 3 strains of laboratory-prepared cultures containing fecal suspensions, and three original isolations of amebae from purged stools, were mailed to the laboratory. In all cases positive cultures were obtained upon cultivation of the tubes at 37°C, after the tubes had been in transit for 2 days.