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Korean J Parasitol > Volume 33(4):1995 > Article

Brief Communication
Korean J Parasitol. 1995 Dec;33(4):387-390. English.
Published online Dec 20, 1995.  http://dx.doi.org/10.3347/kjp.1995.33.4.387
Copyright © 1995 by The Korean Society for Parasitology
Axenization of Entamoeba histolytica, a Korean strain YS-27
Jae-Kyung Chang,Kyung-il Im,* and Chin-Thack Soh
Institute of Tropical Medicine & Department of Parasitology, Yonsei University College of Medicine, Seoul 120-752, Korea.
Received October 16, 1995; Accepted November 21, 1995.


In the present communication, YS-27, a Korean strain of Entamoeba histolytica is described for the isolation and establishment of axenic cultivation. E. histolytica, designated as strain "YS-27", was isolated from the pus of a hepatic abscess obtained from a 72 year old inpatient of August 10, 1969. Specimens, were obtained by needle aspiration, inoculated immediately and weekly cultured in a modified diphasic medium at 37℃. Strain YS-27 had been maintained for more than 15 years by weekly subculture until February, 1985. These cultures were transferred to a monoxenic TTY-SB medium seeded with a trypanosomatid of the genus Crithidia. Penicillin G, 2 to 10 × 103 International units and Streptomycin, 2 to 10 mg per 100 ml, were added to the cultures to eliminate the bacteria. After more than one year later, these two organisms were well maintained by transfer every 3 or 4 days until January, 1986 at 37℃ in TTY-SB medium in the absence of other microorganisms. These monoxenic cultures were then transferred to TYI-S-33 medium. Strain YS-27 alone had not been growing at the time of transfer, but when overlaid with Crithidia at intervals of 3 to 4 days, strain YS-27 propagated well. The Crithidia died out several weeks later after several passages. Beginning in April, 1986, strain YS-27, was successfully established in axenic culture in TYI-S-33 medium and has been maintained in continuous culture and multiplied well to present.


Fig. 1
In vitro propagation of Entamoeba histolytica trophozoites in monoxenic TTY-SB medium (above) and in axenic TYI-S-33 medium.

Fig. 2
72-hours coolnies of Entamoeba histolytica, strain YS-27, grown under axenic conditions in TYI-S-33 medium at 37℃ (left, × 100).


Table 1
Composition of TTY-SB medium for monoxenic cultivation of Entamoeba histolytica.

Table 2
Composition of TYI-S-33 medium for axenic cultivation of Entamoeba histolytica

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