CRITERION™ PHENYLETHANOL AGAR (PEA)

Cat. no. C6610 CRITERION™ PEA Agar 85gm
Cat. no. C6611 CRITERION™ PEA Agar 500gm
Cat. no. C6612 CRITERION™ PEA Agar 2kg
Cat. no. C6613 CRITERION™ PEA Agar 10kg
Cat. no. C6614 CRITERION™ PEA Agar 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Phenylethanol Agar (PEA) is recommended for use in the cultivation and selective isolation of gram-positive bacteria.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Brewer and Lilley reported that the addition of phenylethanol to a nutritive medium will permit growth of gram-positive organisms but markedly to completely inhibit growth of gram-negative organisms found in the same specimen.(10,11) PEA Agar is used for the isolation of enterococci, coagulase-positive staphylococci and most other gram-positive cocci from clinical specimens of mixed gram-positive and gram-negative flora, particularly when specimens are contaminated with swarming Proteus spp. (7)

FORMULA

Gram weight per liter: 42.5gm/L
Casein Peptone 15.0gm
Sodium Chloride 5.0gm
Soy Peptone 5.0gm
Phenylethanol 2.5gm
Agar 15.0gm

Final pH 7.3 +/- 0.2 at 25ºC.

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

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-8ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not homogeneous with soft clumps or if the color has changed from its original beige.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 36.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC. and aseptically add blood and enrichments, if desired.

5. Prepare 5 to 10% blood agar by adding the appropriate volume of sterile defibrinated blood to melted sterile agar medium.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. A90.

LIMITATIONS

A "brown-sugar" appearance is characteristic of dehydrated product and not an indication of deterioration.(3)

Do not store dehydrated medium at room temperature; store in refrigerator, 2- 8ºC. (7)

Medium cannot be depended upon to determine hemolytic patterns; hemolytic reactions are atypical. Recommended that Sheep Blood Agar (SBA) plates by inoculated simultaneously to determine degree of hemolysis, if any.(7)

Some gram-positive cocci may be slightly inhibited on initial incubation (24hr) and may require further incubation to 48 hours for sufficient growth to be evident.(7)

Many gram-negative bacilli may exhibit visible colonies on PEA; however, their size and numbers are smaller than on other selective enteric isolation media.(7)

Avoid over-heating or prolonged heating of medium base which could destroy the capacity of PEA substrate to inhibit gram-negative bacilli.(11)

Pseudomonas aeruginosa is not inhibited on this medium.(7)

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, incubators, blood, and supplements, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Streptococcus pyogenes
ATCC ® 19615
A 24hr 35°C CO 2 ** Growth; beta-hemolysis may appear atypical
Streptococcus pneumoniae
ATCC ® 6305
A 24hr 35°C CO 2 ** Growth; alpha-hemolysis may appear atypical
Staphylococcus aureus
ATCC ® 25923
A 24hr 35°C CO 2 ** Growth
Proteus mirabilis
ATCC ® 12453
B 18-24hr 35°C Aerobic Partial to complete inhibition; slight growth without swarming

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ PEA Agar powder should appear homogeneous with soft clumps, and beige in color. The prepared media with sheep blood should appear opaque, and dark red in color.

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. Ellner, et al. 1966. Am. Journ. Clin. Path.; 45:502.

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

7. MacFaddin, J.F. 1985. Media for Isolation, Cultivation, Identification, Maintenance of Bacteria, Vol. I. Williams & Wilkins, Baltimore, MD.

8. FDA. 1995. Bacteriological Analytical Manual, 8th ed. FDA.

9. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

10. Brewer, J.H., et al. 1949. Paper presented at the December meeting of the Maryland Association of Medical and Public Health Laboratories.

11. Lilley, B.D., et al. 1953. The selective antibacterial action of phenylethylalcohol. J. Pharm. Assoc.; 42:6.


ATCC is a registered trademark of the American Type Culture Collection.

061416gr