A small amoeboid organism, found in mammalian tissue cultures inoculated with an infective agent formerly termed ‘Ryan virus’, is shown to have the morphological, cultural and behavioural characters of the free-living soil amoeba Hartmannella castellanii Douglas, 1930. Cytopathic changes occurred regularly in the infected monolayers; this was evidently due to action of the amoebae rather than the presence of any associated bacterial or viral agents. Strong circumstantial evidence suggests that the Ryan isolates of H. castellanii originated, either as trophozoites or cysts, from swabs of the human nasopharynx. Recovery of hartmannellid amoebae from this source is of interest in relation to some recently reported cases of pyogenic meningitis, apparently caused by free-living soil amoebae.
AlexeieffA.1912b; Quelques remarques supplémentaires sur la systématique des Amibes du groupe Limax. Sur le genre Sappina Dangeard. Bull. Soc. zool. Fr 37:149
ChangR. S.1961; Properties of a transmissible agent capable of inducing marked DNA degradation and thymine catabolism in a human cell. Proc. Soc. exp. Biol. Med107135
SinghB. N.1952; Nuclear division in nine species of small free-living amoebae and its bearing on the classification of the order Amoebida. Phil. Trans. R. Soc. B 236:405
van RooyenC. E.1932b; Observations on the clearing effect of Amoeba (Hartmannella) castellanii on bacterial cultures: a phenomenon simulating bacteriophagy. J. trop. Med. Hyg 35:259
WangS. S.,
FeldmanH. A.1961; Occurrence of Acanthamoeba in tissue cultures inoculated with human pharyngeal swabs. In Antimicrobial Agents and Chemotherapy150FinlandM.,
SavageG. M.
Michigan: Braun-Brumfield Inc;