BLOOD AGAR ENHANCED HEMOLYSIS (EH)

Cat. no. A03 Blood Agar EH, 5%, 15x100mm Plate, 17ml 10 plates/bag

INTENDED USE

Hardy Diagnostics Blood Agar Enhanced Hemolysis (EH) is recommended for use as a general purpose growth medium for the isolation, cultivation, and differentiation of fastidious microorganisms from specimens where clear and distinct hemolytic reactions are of prime importance.

SUMMARY

Modified Tryptic Soy Agar is the basal medium for Blood Agar EH. This medium contains peptic digest of soybean meal, sodium chloride, agar, and modified pancreatic digest of casein (Tryptone H Plus). Sheep blood has been added to facilitate the growth of some organisms, and for the observation of hemolytic reactions. The absence of reducing sugars and carbohydrates allows hemolysis to occur without hindrance. Enhanced hemolysis is a result of Tryptone H Plus; this modified base enhances the production of hemolysin while minimizing antagonism or loss in activity of streptococcal hemolysins. (6)

Compared to traditional Blood Agar, Blood Agar EH produces larger, clearer zones of hemolysis groups A, C and G streptococci. Perrollaz et al. reported zone sizes to be 39% larger than with traditional media. Hemolysis was also found to develop more rapidly on Blood Agar EH. (7)

FORMULA

Ingredients per liter of deionized water:*

Pancreatic Digest of Casein 15.0gm
Peptic Digest of Soybean Meal 5.0gm
Sodium Chloride 5.0gm
Sheep Blood 50.0ml
Agar 12.0gm

Final pH 7.3 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Storage: Upon receipt store at 2-8ºC. away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), hemolysis, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat and freezing.

PRECAUTIONS

PROCEDURE

Specimen Collection: Infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport media and refrigerated until inoculation. Consult listed references for information on specimen collection. (1-5)

Prepared media should be inoculated, incubated, and results recorded according to accepted procedures described in the listed reference texts. (1-5)

LIMITATIONS

Since all hemolysis is enhanced, Blood Agar EH is not recommended for use with the CAMP test.

Zones of inhibition around Bacitracin Disks may be difficult to read.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Streptococcus pneumoniae
ATCC ® 6305***
A 24hr 35°C CO 2 ** Growth, alpha-hemolysis
Streptococcus pyogenes
ATCC ® 19615***
A 24hr 35°C CO 2 ** Growth, beta-hemolysis
Staphylococcus aureus
ATCC ® 25923
A 24hr 35°C CO 2 ** Growth, beta-hemolysis
Escherichia coli
ATCC ® 25922
A 24hr 35°C CO 2 ** Growth, beta-hemolysis

** Atmosphere of incubation is enriched with 5-10% CO 2 .

*** Recommended QC strains for User Quality Control according to the CLSI document M22 when applicable.

User Quality Control

PHYSICAL APPEARANCE

Blood Agar EH should appear opaque, and cherry red in color.

S. pyogenes growing on Blood Agar EH

Streptococcus pyogenes (ATCC ® 19615) colonies growing on Blood Agar EH, 5% (Cat. no. A03). Incubated in CO 2 for 24 hours at 35ºC.

Escherichia coli (ATCC ® 25922) colonies growing on Blood Agar EH, 5% (Cat. no. A03). Incubated in CO 2 for 24 hours at 35ºC.

S. aureus growing on Blood Agar, EH

Staphylococcus aureus (ATCC ® 25923) colonies growing on Blood Agar EH, 5% (Cat. no. A03). Incubated in CO 2 for 24 hours at 35ºC.

S. pneumoniae growing on Blood Agar, EH

Streptococcus pneumoniae (ATCC ® 6305) colonies growing on Blood Agar EH, 5% (Cat. no. A03). Incubated in CO 2 for 24 hours at 35ºC.

REFERENCES

1. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

2. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

3. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

4. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

5. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

6. Bacto® Tryptic Soy Blood Agar Base EH, Difco Laboratories, Detroit, MI, 1991.

7. Perrollaz, et al. 1992. A Comparative Evaluation of Commercially Available Tryptic Soy and Columbia Blood Agar Base Media, 1992 ASM General Meeting, New Orleans, LA.


ATCC is a registered trademark of the American Type Culture Collection.
Bacto is a registered trademark of Difco Laboratories, Detroit, MI.

121415hh