FIG. 1. Tryptic soy agar with and without Sheep Blood. (Rebecca Buxton, University of Utah)
FIG. 2. Beta hemolytic Streptococcus species seen with transmitted light, Streptococcus pyogenes (Lancefield group A. Also see Figures 28-35). (Rebecca Buxton, University of Utah)
FIG. 3. Normal Upper respiratory flora mixed with Streptococcus species. (The presence of beta-hemolytic colonies indicates the possibility of Streptococcus pyogenes infection. Also see Figures 26 and 27). (Rebecca Buxton, University of Utah)
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. (Rebecca Buxton, University of Utah)
FIG. 5. Normal Upper respiratory flora mixed with Streptococcus pyogenes demonstrating production of Streptolysin O. Beta hemolysis is only evident where the agar was "stabbed". (Rebecca Buxton, University of Utah)
FIG. 6. Normal Upper respiratory flora mixed with Streptococcus pyogenes demonstrating production of Streptolysin O. Beta hemolysis is only evident where the agar was "stabbed". (Rebecca Buxton, University of Utah)
FIG. 7. Streptococcus agalactiae (Lancefield group B) viewed with incident light: No obvious hemolysis. (Rebecca Buxton, University of Utah)
FIG. 8. Streptococcus agalactiae (Lancefield group B) viewed with transmitted light: Subtle hemolysis. (Also see Figure 36 and 37). (Rebecca Buxton, University of Utah)
FIG. 9. Listeria monocytogenes, removing colonies to see the subtle hemolysis directly beneath the colonies. (Rebecca Buxton, University of Utah)
FIG. 10. Alpha-hemolytic Streptococcus species "Viridans group" streptococci, including species such as the Streptococcus mutans, mitis, and salivarius groups display alpha hemolysis. (Also see Figures 15,16 and 23-25). (Rebecca Buxton, University of Utah)
FIG. 11. Alpha hemolysis of Streptococcus pneumoniae (Encapsulated strain, also see Figure 17-20). (Rebecca Buxton, University of Utah)
FIG.12. "Gamma Streptococcus": Enterococcus faecalis (24 hours, non-hemolytic). "Gamma streptococci" 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, was considered a "gamma Streptococcus species," and usually reacts as Lancefield group D). (Rebecca Buxton, University of Utah)
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." (See also Figure 38). (Rebecca Buxton, University of Utah)
FIG. 14. Alpha (a), Beta (b) and Non-hemolytic (Gamma, g) streptococci (transmitted light). (Rebecca Buxton, University of Utah)
FIG. 15. Alpha-hemolytic Streptococcus species ("Viridans group"). (Rebecca Buxton, University of Utah)
FIG. 16. Alpha-hemolytic Streptococcus species ("Viridans group"). (Rebecca Buxton, University of Utah)
FIG. 17. In addition to alpha hemolysis, this strain of Streptococcus pneumoniae is producing abundant polysaccharide capsular material evidenced by the mucoid or "oil droplet" appearance on the colonies. (Rebecca Buxton, University of Utah)
FIG. 18. Streptococcus pneumoniae (encapsulated strain). (Rebecca Buxton, University of Utah)
FIG. 19. Streptococcus pneumoniae (encapsulated strain). (Rebecca Buxton, University of Utah)
FIG. 20. Streptococcus pneumoniae (encapsulated strain). (Rebecca Buxton, University of Utah)
FIG. 21. Streptococcus pneumoniae (encapsulated strain). (Rebecca Buxton, University of Utah)
FIG. 22. Streptococcus pneumoniae (encapsulated strain). (Rebecca Buxton, University of Utah)
FIG. 23. Mixed alpha- and non-hemolytic colonies are typical of normal upper respiratory (mouth) flora. (Rebecca Buxton, University of Utah)
FIG. 24. Mixed alpha- and non-hemolytic colonies are typical of normal upper respiratory (mouth) flora. (Rebecca Buxton, University of Utah)
FIG. 25. Mixed alpha- and non-hemolytic colonies are typical of normal upper respiratory (mouth) flora. (Rebecca Buxton, University of Utah)
FIG. 26. Normal Upper respiratory flora mixed with beta-hemolytic Streptococcus species (S. pyogenes). (Rebecca Buxton, University of Utah)
FIG. 27. Normal Upper respiratory flora mixed with beta-hemolytic Streptococcus species (S. pyogenes). (Rebecca Buxton, University of Utah)
FIG. 28. Beta hemolytic Streptococcus species: Streptococcus pyogenes (Lancefield group A). (Rebecca Buxton, University of Utah)
FIG. 29. Beta hemolytic Streptococcus species: Lancefield group C. (Rebecca Buxton, University of Utah)
FIG. 30. Beta hemolytic Streptococcus species: Lancefield group C (transmitted light). (Rebecca Buxton, University of Utah)
FIG. 31. Beta hemolytic Streptococcus species: Lancefield group C (Large colony types of Lancefield groups A, C, and G can appear very similar on blood agar plates). (Rebecca Buxton, University of Utah)
FIG. 32. Lancefield group F streptococci (beta-hemolytic strains of the Streptococcus anginossus group) produce very small (so called “minute”) colonies which are beta hemolytic, but because of their size and slower growth, the complete clearing of red blood cells may be difficult to appreciate. (Rebecca Buxton, University of Utah)
FIG. 33. Beta hemolytic Streptococcus species: Lancefield group F. (Rebecca Buxton, University of Utah)
FIG. 34. Beta hemolytic Streptococcus species: Lancefield group F. (Rebecca Buxton, University of Utah)
FIG. 35. Beta hemolytic Streptococcus species: Lancefield group F. (Rebecca Buxton, University of Utah)
FIG. 36. Beta hemolytic Streptococcus species: Streptococcus agalactiae (Lancefield group B). (Rebecca Buxton, University of Utah)
FIG. 37. Beta hemolytic Streptococcus species: Streptococcus agalactiae (Lancefield group B) Hemolysis may be difficult to appreciate, and may never completely clear the cells. (Compare with the complete hemolysis of Streptococcus pyogenes, Figure 4 (also see Figures 7 and 8 ). (Rebecca Buxton, University of Utah)
FIG. 38. "Gamma Streptococcus" : Enterococcus faecalis (48 hours, slight alpha hemolysis. Also see Figures 12 and 13). (Rebecca Buxton, University of Utah)
FIG. 39. Streptococcus bovis (Lancefield group D) may appear very similar to some Enterococcus species. (Rebecca Buxton, University of Utah)
FIG. 40. Streptococcus bovis (Lancefield group D). (Rebecca Buxton, University of Utah)
FIG. 41. Streptococcus bovis (Lancefield group D). (Rebecca Buxton, University of Utah)
FIG. 42. Streptococcus bovis (Lancefield group D). (Rebecca Buxton, University of Utah)
See also:
Blood Agar Plates and Hemolysis: Bacillus species (8 images)
Blood Agar Plates and Hemolysis: Family Enterobacteriaceae (9 images)
Blood Agar Plates and Hemolysis: Non-Fermenting Gram-Negative Rods (including Pseudomonas aeruginosa) (5 images)
Blood Agar Plates and Hemolysis: Non-Sporeforming Gram-Positive Rods (Aerobic) (2 images)
Blood Agar Plates and Hemolysis: Staphylococcus and Other Catalase Positive Gram-Positive Cocci (11 images)
PROTOCOL
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REVIEWERS
This resource was peer-reviewed at ASM Conference for Undergraduate Education 2005 (ASMCUE, 2005).
Participating Reviewers:
Samuel Fan
Bradley University, Peoria, Ill.
Ashalla Freeman
University of North Carolina, Chapel Hill, N.C.
Roxana Hughes
UNT Biological Sciences, Denton, Tex.
D. Sue Katz
Rogers State University, Claremore, Okla.
Lucy Kluckhohn Jones
Santa Monica College, Santa Monica, Calif.
Patricia Shields
University of Maryland, College Park
Erica Suchman
Colorado State University, Ft. Collins | 
