ANIMAL BLOOD PRODUCTS

Animal blood products are employed in a variety of laboratory procedures, including their addition to culture media for added enrichment and determination of hemolytic reactions of microorganisms. Animal blood products also serve as sources of stabilized, washed, pooled red blood cells for use in serological procedures.

The animal blood types frequently used in the production of culture media are sheep, horse, rabbit and bovine blood. Our animal blood is obtained from controlled herds that are kept free of antimicrobic drugs and disease. All animals are maintained in a healthy condition and treated humanely in accordance with government regulations. 

Below is a list of some of the growth factors that are commonly used as ingredients in various culture media.

Animal Blood, Alsevers is the most stable blood preparation. It contains equal amounts of blood and modified Alsevers solution, which serves as the anticoagulant. Alsevers Blood serves as a source of erythrocytes for serological procedures and is recommended for laboratories that wish to prepare their own washed cell preparations.

Animal Blood, Citrated is blood that has been washed and treated with sodium citrate as the anticoagulant. It serves as a source of erythrocytes for serological procedures.

Bovine Albumin contains bovine albumin fraction V, 0.2% in 0.85% saline solution.

Bovine Blood, Defibrinated is calf blood that has been treated to denature fibrinogen without causing cell lysis. It is used to supplement blood agar bases. Defibrinated bovine blood is free of anticoagulant or preservative. It is recommended for use in the study of animal pathogens and veterinary research.

Chocolatized Defibrinated Blood is defibrinated blood that has been heated to release additional growth factors that would otherwise remain unavailable within intact red blood cells. Heat stable hemin (X-factor) and heat labile nicotinamide adenine dinucleotide (V-factor) are the growth factors readily available in chocolatized media.

Egg Yolk Emulsion consists of chicken egg yolks and whole chicken egg.

Egg Yolk Emulsion, 50% consists of chicken egg yolks, whole chicken egg, and saline solution.

Fildes Enrichment is a peptic digest of sheep or horse blood that serves as a rich source of growth factors including hemin (X-factor) and nicotinamide adenine dinucleotide (V-factor).

Hemin Solution is a mixture of hemin and NaOH.

Hemoglobin, Dried Bovine is used to provide hemin required by many fastidious microorganisms.

Hemoglobin Solution, 2% provides hemin required by many fastidious microorganisms.

Horse Blood, Defibrinated is horse blood that has been treated to denature fibrinogen without causing cell lysis. It is used to supplement blood agar bases. It does not release V-factor hydrolyzing enzymes, and supports the growth of the hemolytic Haemophilus species. Defibrinated horse blood is free of anticoagulant or preservative. Because defibrinated horse blood may result in "incorrect" hemolytic reactions as compared to reactions on sheep blood media, definitive tests are recommended for the differentiation of group D streptococci from group A.(3)

Horse Blood, Hemolyzed is horse blood that has been treated to lyse cells.

Horse Blood, Oxalated is horse blood that has been treated with potassium oxalate as an anticoagulant.

Horse Blood, with Heparin is whole horse blood treated with the anticoagulant heparin. Heparin-binding of Mycobacterium tuberculosis has been suggested to increase the organism's virulence in primary infection and in extrapulmonary dissemination(5)

Laked Blood is defibrinated blood that has been processed with freeze/thaw cycles to hemolyze the red blood cells. It is clear, red, and homogenous and provides many nutrients. It is useful for growing fastidious organisms due to its highly available nutrient contents.

Plasma is the clear yellowish fluid portion of blood in which cells are suspended. Plasma contains the protein fibrinogen.

Rabbit Blood, Defibrinated is rabbit blood that has been treated to denature fibrinogen without causing cell lysis. It is used to supplement blood agar bases. It does not release V-factor hydrolyzing enzymes, and supports the growth of the hemolytic Haemophilus species.(3) Defibrinated rabbit blood produces "correct" hemolytic reactions, and is free of anticoagulant or preservative.(3)

Serum is the clear yellowish fluid obtained when whole blood is separated into its liquid and solid components. Blood is allowed to clot so that the serum separates from the blood cells. The liquid portion released from the clot is called serum and does not contain fibrinogen as the fibrinogen was utilized to form the fibrin threads of the blood clot. Serum usually is inactivated by heating to 56 degrees C. for 30 minutes to eliminate lipases that would cause degradation of lipids and inactivation of complement.

Sheep Blood, Defibrinated is sheep blood that has been treated to denature fibrinogen without causing cell lysis. It has been shown to be the most accurate blood preparation for the determination of hemolytic activity of streptococci.(3) Sheep blood also contains enzymes that hydrolyze V-factor, thereby inhibiting growth of V-factor dependent Haemophilus haemolyticus which potentially could be misidentified as hemolytic streptococci.(3) Defibrinated sheep blood is free of anticoagulant or preservative. Because washed cell suspensions could result in fragile, hemolyzed blood cells, defibrinated sheep blood is not recommended as a source of washed cells.

Washed, Sheep Cell Suspensions are stabilized preparations of concentrated erythrocytes. A working solution is prepared by diluting the concentrated suspension. It is not recommended that the suspension be washed.

REFERENCES

1. Atlas, R.M., 2010. Handbook of Microbiological Media. Revised/Expanded ed. Washington, D.C., ASM.

2. Brown, B.A. 1993. Hematology: Principles and Procedures, 6th ed., Lea & Febiger.

3. Versalovic, J., et al. 2011. Manual of Clinical Microbiology, 10th ed. American Society for Microbiology, Washington, D.C.

4. Koneman, E.W., et al. 2006. Color Atlas and Textbook of Diagnostic Microbiology, 7th ed. J. B. Lippincott Company, Philadelphia, PA.

5. Pethe, Kevin, et al. "The heparin-binding haemagglutinin of M. tuberculosis is required for extrapulmonary dissemination." Nature 412.6843 (2001): 190-194.


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