Blood Agar Plates and Hemolysis Protocols
- Author: Rebecca Buxton1
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VIEW AFFILIATIONS HIDE AFFILIATIONSAffiliations: 1: Department of Pathology, University of Utah, Salt Lake City, UT, 84132
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Citation: Rebecca Buxton. 2005. Blood agar plates and hemolysis protocols.
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Publication Date : September 2005
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Category: Protocol

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Figures

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Figure 1
FIG. 1. Tryptic Soy Agar with and without sheep blood

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Figure 2
FIG. 2. Beta hemolytic Streptococcus species, Streptococcus pyogenes (transmitted light) (Lancefield group A).

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Figure 3
FIG. 3.Normal Upper respiratory flora mixed with beta-hemolytic Streptococcus species. (The presence of beta-hemolytic colonies indicates the possibility of Streptococcus pyogenes infection.)

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Figure 4
FIG. 4. Same blood agar plate as Figure 2 demonstrating that the beta hemolysis of Streptococcus pyogenes is so complete that print my be read through the resulting transparent medium.

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Bacillus cereus (Enlarged view)
FIG. 5. Normal Upper respiratory flora mixed with Streptococcus pyogenes demonstrating production of Streptolysin O.

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Figure 6
FIG. 6. Beta hemolysis is only evident where the agar was "stabbed".

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Figure 7
FIG. 7. Streptococcus agalactiae (Lancefield group B) viewed with incident light: No obvious hemolysis.

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Figure 8
FIG. 8. Streptococcus agalactiae (Lancefield group B) viewed with transmitted light: Subtle hemolysis.

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Figure 9
FIG. 9. Listeria monocytogenes, removing colonies to see the subtle pink hemolysis directly beneath the colonies.

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Figure 10
FIG. 10. Alpha-hemolytic Streptococcus species "Viridans group" streptococci, including species such as the Streptococcus mutans, mitis, and salivarius groups display alpha hemolysis.

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Figure 11
FIG. 11. Alpha hemolysis of Streptococcus pneumoniae (Encapsulated strain).

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Figure 12
FIG. 12. "Gamma Streptococcus" or Enterococcus faecalis (24 hours, non-hemolytic). "Gamma streptococcus" are usually non-hemolytic after 24 hours of incubation, but many eventually display weak alpha hemolysis. (The genus Enterococcus was once a part of the Streptococcus genus, and was considered a "gamma Streptococcus species". Enterococci usually reacts as Lancefield group D.)

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Figure 13
FIG. 13. The same Enterococcus strain as Figure (12), shown with transmitted light at 48 hours incubation demonstrates the alpha hemolysis of some "gamma streptococci."