The action of amoebicidal drugs on Entamoeba invadens Rodhain, 1934 in vitro

Abstract

1. A method, based on that devised for E. histolytica by Dobell (1947), was worked out for testing the action of drugs upon E. invadens.2. The sensitivity of di- and monobacterial strains of E. invadens to emetine was determined, and of a dibacterial strain to the quinaldines A 352, A 356 and A 404. E. invadens was killed by emetine at concentrations of 1/50,000–1/100,000, A 352 or A 356 at 1/100,000, and A 404 at 1/10,000. The strains of E. invadens used in the present tests are thus less sensitive to emetine than is E. histolytica, but the sensitivity of the two species to the quinaldines is similar.3. A strain of E. invadens which was maintained for 9 months in the presence of increasing concentrations of emetine, did not become resistant to the drug.I am indebted to Dr A. Bishop for much advice and criticism; to Dr J. D. Fulton for a culture of Bacterium coli A'; and to Dr J. Walker for supplies of the compounds A 352, A 356 and A404. The work has been financed by the Medical Research Council.