• Quick Order
  • Careers
  • Support

Entamoeba histolytica Schaudinn


Product category
Amoebozoa, Entamoebida
Strain designation
Type strain
Isolation source
Canadian with amebic dysentery probably acquired in Honduras
Enteric disease research
Infectious disease research
Product format
Storage conditions
-80°C or colder for 1 week, vapor phase of liquid nitrogen for long-term storage
Mission Collection Item
This is a Mission Collection Item.


ATCC determines the biosafety level of a material based on our risk assessment as guided by the current edition of Biosafety in Microbiological and Biomedical Laboratories (BMBL), U.S. Department of Health and Human Services. It is your responsibility to understand the hazards associated with the material per your organization’s policies and procedures as well as any other applicable regulations as enforced by your local or national agencies.

ATCC highly recommends that appropriate personal protective equipment is always used when handling vials. For cultures that require storage in liquid nitrogen, it is important to note that some vials may leak when submersed in liquid nitrogen and will slowly fill with liquid nitrogen. Upon thawing, the conversion of the liquid nitrogen back to its gas phase may result in the vial exploding or blowing off its cap with dangerous force creating flying debris. Unless necessary, ATCC recommends that these cultures be stored in the vapor phase of liquid nitrogen rather than submersed in liquid nitrogen.

Required Products

These products are vital for the proper use of this item and have been confirmed as effective in supporting functionality. If you use alternative products, the quality and effectiveness of the item may be affected.

Detailed product information


Specific applications
Enteric Research
Food and waterborne pathogen research

Handling information

Instruction for complete medium
ATCC Medium 1171 grown with mixed bacteria (Quality controlled lots of this medium are commercially available from ATCC as cat. no. PRA-1171)
Culture system
Handling procedure
Storage and Culture Initiation
Frozen ampules packed in dry ice should either be thawed immediately or stored in liquid nitrogen.  If liquid nitrogen storage facilities are not available, frozen ampules may be stored at or below -70°C for approximately one week.  Do not under any circumstance store frozen ampules at refrigerator freezer temperatures (generally -20°C).  Storage of frozen material at this temperature will result in the death of the culture.
  1. One day before thawing a frozen ampule inoculate two tubes of ATCC medium 1171 with the bacterial flora only.  Incubate the tubes on a 15° horizontal slant at 35°C.  If the specific bacterial flora associated with this culture are not available, skip this step and proceed to step 2.
  2. On the following day combine 4.1 mL ATCC medium 1171 with 0.9 mL of HIBS (heat-inactivated bovine serum) to produce 5 mL of medium enriched with 20% serum.  Invert gently several times to mix.  Note:  If bacterized medium 1171 was prepared in step 1, use the bacterized medium in place of fresh medium for faster recovery/growth.
  3. Remove the frozen ampule from liquid nitrogen and flame gently at the base of the cap.  Remove the cap and aseptically add 0.5 mL of the serum-enriched medium prepared in step 2.  Place in a 35°C water bath until thawed (2-3 min).  Note:  Manipulations of the ampule before placing in the water bath should be done as quickly as possible to avoid warming of the contents at a suboptimal rate.
  4. Transfer contents of the thawed ampule to a one-dram screw-capped vial (vial holds approximately 4.0 mL).
  5. Add 2.5 mL of serum-enriched medium prepared in step 2 to the vial in dropwise fashion.  Tighten the cap and incubate on a 15° horizontal slant at 35°C for 2-3 hours.
  6. Ice the vial for 10 minutes, then invert gently 10 times. Centrifuge the vial at 100-200 x g for 5 min.
  7. Aspirate the supernatant leaving approximately 0.5 mL.  Note:  Do not aspirate the pelleted material. 
  8. Replace the supernatant with 3.0 mL of the bacterized medium 1171 prepared in step 1 if available; otherwise use fresh medium 1171 (i.e., not serum-enriched).
  9. Incubate the vial on a 15° horizontal slant at 35°C with the cap screwed on tightly.  Observe the culture daily and transfer when many trophozoites are observed (i.e., early stationary phase).
Handling notes
This xenic culture contains the original bacterial flora present when the amoeba was first isolated. In general, addition of penicillin G at 75 U/ml and streptomycin at 75 µg/mL to ATCC Medium 1171 may be necessary if the bacterial density in the culture is too high.  Inoculate fresh tubes of media with bacteria at least one day prior to subcultivation and prior to addition of antibiotics, if used.
Culture maintenance
  1. Ice a test tube culture at or near peak density for 10 minutes, invert 20 times and aseptically transfer a 0.1 and 0.3 mL aliquot to a fresh tube of ATCC medium 1171.
  2. Screw cap on tightly and incubate on a 15° horizontal slant at 35°C.  Transfer when many trophozoites are observed (i.e., early stationary phase).

Notes:  In general, better growth can often be achieved by using media pre-inoculated with bacteria.  Addition of penicillin G at 75 U/mL and streptomycin at 75 µg/mL to ATCC Medium 1171 may be necessary if the bacterial density in the culture is too high.  Inoculate fresh tubes of media with bacteria at least one day prior to subcultivation and prior to addition of antibiotics, if used.  Also, nutrients in ATCC medium 1171 may be diluted through use of an osmotically-balanced saline buffer such as Dulbecco's PBS (ATCC 30-2200) with the medium.  Mixtures in the range of 1:1 to 3:1 (medium to buffer) usually work well to control or limit bacterial growth in cultures where other methods are not sufficient.

Reagents for cryopreservation
CPMB-5 Cryoprotective Solution
DMSO, 1.0 mL
2.5 M Sucrose, 0.8 mL
L-Cysteine/Ascorbic Acid Solution, 0.2 mL
CPMB-2 Basal Solution, 6.0 mL
HIBS, 2.0 mL

CPMB-2 Basal Solution
Yeast Extract, 60.0 g
K2HPO4, 1.0 g
KH2PO4, 0.6 g
NaCl, 2.0 g
Distilled water, 1.0 L
Autoclave for 15 minutes.

L-Cysteine/Ascorbic Acid Solution
L-Cysteine-HCL, 1.0 g
Acorbic Acid, 0.1 g
Distilled water, 10.0 mL

Add 9.0 mL of distilled water to a 20 mL beaker and dissolve the first two components.  While stirring, adjust the pH to 7.2 with 10N NaOH (approximately 0.7 mL).  Adjust final volume to 10 mL with distilled water and filter sterilize. Solution should be used soon after preparation.  Discard any unused solution.
  1. Mix the components in the order listed. When the medium is added to the DMSO the solution will warm up due to chemical heat.
  2. Harvest cells from a culture that is at or near peak density by filtration and centrifugation at 800 x g for 5 min.
  3. Adjust the concentration of cells to at least 2 x 106/ml in fresh medium.
  4. Mix the cell preparation and the cryoprotective solution in equal portions.
  5. Dispense in 0.5 ml aliquots into 1.0 - 2.0 ml sterile plastic screw-capped cryules (special plastic vials for cryopreservation).
  6. Place vials in a controlled rate freezing unit. From room temperature cool at -1°C/min to -40°C. If freezing unit can compensate for the heat of fusion, maintain rate at -1 C/min through heat of fusion. At -40°C plunge ampules into liquid nitrogen. Alternatively, place the vials in a Nalgene 1°C freezing apparatus. Place the apparatus at -80°C for 1.5 to 2 hours and then plunge ampules into liquid nitrogen.  (The cooling rate in this apparatus is approximately -1°C/min.)  
  7. Ampules are stored in either the vapor or liquid phase of a nitrogen refrigerator.
  8. To establish a culture from the frozen state place the vial in a 35°C water bath.  Immerse the vial to a level just above the surface of the frozen material. Do not agitate the vial.   Immediately after thawing, do not leave in water bath, aseptically remove the contents of the ampule and inoculate into a T-25 tissue culture flask containing 10 ml ATCC medium 802 bacterized with Klebsiella pneumoniae subsp. pneumoniae (ATCC® 700831™) or Enterobacter aerogenes (ATCC® 13048™).
  9. Incubate at 25°C with the cap screwed on tightly.
  10. Once the culture is established, vigorously agitate the flask and aseptically transfer 0.5 ml to 10.0 ml of bacterized ATCC medium 802. Follow the protocol for maintenance of culture.


Deposited as
Entamoeba histolytica Schaudinn
LS Diamond
Type of isolate
Year of origin

Legal disclaimers

Intended use
This product is intended for laboratory research use only. It is not intended for any animal or human therapeutic use, any human or animal consumption, or any diagnostic use.

The product is provided 'AS IS' and the viability of ATCC® products is warranted for 30 days from the date of shipment, provided that the customer has stored and handled the product according to the information included on the product information sheet, website, and Certificate of Analysis. For living cultures, ATCC lists the media formulation and reagents that have been found to be effective for the product. While other unspecified media and reagents may also produce satisfactory results, a change in the ATCC and/or depositor-recommended protocols may affect the recovery, growth, and/or function of the product. If an alternative medium formulation or reagent is used, the ATCC warranty for viability is no longer valid.  Except as expressly set forth herein, no other warranties of any kind are provided, express or implied, including, but not limited to, any implied warranties of merchantability, fitness for a particular purpose, manufacture according to cGMP standards, typicality, safety, accuracy, and/or noninfringement.


This product is intended for laboratory research use only. It is not intended for any animal or human therapeutic use, any human or animal consumption, or any diagnostic use. Any proposed commercial use is prohibited without a license from ATCC.

While ATCC uses reasonable efforts to include accurate and up-to-date information on this product sheet, ATCC makes no warranties or representations as to its accuracy. Citations from scientific literature and patents are provided for informational purposes only. ATCC does not warrant that such information has been confirmed to be accurate or complete and the customer bears the sole responsibility of confirming the accuracy and completeness of any such information.

This product is sent on the condition that the customer is responsible for and assumes all risk and responsibility in connection with the receipt, handling, storage, disposal, and use of the ATCC product including without limitation taking all appropriate safety and handling precautions to minimize health or environmental risk. As a condition of receiving the material, the customer agrees that any activity undertaken with the ATCC product and any progeny or modifications will be conducted in compliance with all applicable laws, regulations, and guidelines. This product is provided 'AS IS' with no representations or warranties whatsoever except as expressly set forth herein and in no event shall ATCC, its parents, subsidiaries, directors, officers, agents, employees, assigns, successors, and affiliates be liable for indirect, special, incidental, or consequential damages of any kind in connection with or arising out of the customer's use of the product. While reasonable effort is made to ensure authenticity and reliability of materials on deposit, ATCC is not liable for damages arising from the misidentification or misrepresentation of such materials.

Please see the material transfer agreement (MTA) for further details regarding the use of this product. The MTA is available at

Permits & Restrictions

Import Permit for the State of Hawaii

If shipping to the U.S. state of Hawaii, you must provide either an import permit or documentation stating that an import permit is not required. We cannot ship this item until we receive this documentation. Contact the Hawaii Department of Agriculture (HDOA), Plant Industry Division, Plant Quarantine Branch to determine if an import permit is required.


Frequently Asked Questions


Curated Citations

Chadee K, Meerovitch E. Entamoeba histolytica: early progressive pathology in the cecum of the gerbil (Meriones unguiculatus). Am. J. Trop. Med. Hyg. 34: 283-291, 1985. PubMed: 2858986

CG Clark, personal communication

Need assistance with this product? Contact our Technical Support team.


US and Puerto Rico

Outside the US

Hours of Operation

9:00am - 5:00pm
US Eastern Time