CRITERION™ MUELLER HINTON BROTH

Cat. no. C7520 CRITERION™ Mueller Hinton Broth 42gm
Cat. no. C7521 CRITERION™ Mueller Hinton Broth 500gm
Cat. no. C7522 CRITERION™ Mueller Hinton Broth 2kg
Cat. no. C7523 CRITERION™ Mueller Hinton Broth 10kg
Cat. no. C7524 CRITERION™ Mueller Hinton Broth 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Mueller Hinton Broth is recommended for use in the cultivation of a wide variety of microorganisms. Mueller Hinton Broth is also recommended for antimicrobial susceptibility testing of aerobic microorganisms by broth dilution methods.(7)

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

Mueller and Hinton developed Mueller Hinton media in 1941 to be a protein free medium for isolating pathogenic strains of Neisseria.(8) Mueller Hinton Broth is recommended for the cultivation of microorganisms, and for making dilutions of organisms to be used in the Kirby-Bauer disk diffusion procedure. Broth dilution antimicrobial susceptibility testing can be performed using Mueller Hinton Broth.

CRITERION™ Mueller Hinton Broth contains the same ingredients as Mueller Hinton Agar, with the exception of the solidifying agent. Mueller Hinton Broth contains beef infusion, casamino acids and starch. Starch acts as a colloid that protects against toxic material in the media. Beef infusion and casamino acids are provided as a source of energy and nutrients.

FORMULA

Gram weight per liter: 21.0gm/L
Acid Hydrolysate of Casein 17.5gm
Beef Extract 2.0gm
Starch 1.5gm

Final pH 7.3 +/- 0.1 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 2-30ºC. 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 free-flowing or if the color has changed from its original light beige.

Store the prepared media at 2-30ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 21.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat as necessary to dissolve completely.

3. Dispense Mueller Hinton Broth as desired.

4. Autoclave at 121ºC. for 15 minutes.

5. Check prepared Mueller Hinton Broth to ensure the final pH is 7.3 +/- 0.1 at 25ºC.

6. Adjust cation content as necessary to meet performance requirements. Refer to the product container label for lot specific cation concentration. Consult listed references for information regarding cation adjustments.(7)

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. R38.

LIMITATIONS

Some strains may be encountered that fail to grow or grow poorly in this broth.

Inoculum size, rate of growth, medium formulation and pH, length of incubation and incubation environment, drug diffusion rate, and measurement of endpoints can affect results. It is recommended that procedures are accurately followed to ensure reliable results.(5)

Thymidine in excessive amounts can reverse the inhibitory effects of sulfonamides and trimethoprim.(7)

Variation in the concentration of divalent cations, primarily calcium an magnesium, affects results of aminoglycoside, tetracycline, and colistin tests with P. aeruginosa isolates. A cation content that is too high reduces zone sizes, where as a cation content that is too low has the opposite effect.

A pH outside the range of 7.3 +/- 0.1 may adversely affect susceptibility test results. If the pH is too low, aminoglycosides and macrolides will appear to lose potency; others may appear to have excessive activity. The opposite effects are possible if the pH is too high.(1)

Mueller Hinton Broth should be inoculated within 15 minutes after preparing the inoculum suspension.(1)

MATERIALS REQUIRED BUT NOT PROVIDED

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

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
A 24hr 35°C Aerobic Growth
Staphylococcus aureus
ATCC ® 25923
A 24hr 35°C Aerobic Growth
Enterococcus faecalis
ATCC ® 29212
A 24hr 35°C Aerobic Growth
Pseudomonas aeruginosa
ATCC ® 27853
A 24hr 35°C Aerobic Growth

Each lot of CRITERION™ Mueller Hinton Broth powder has been tested to determine calcium ion and magnesium ion concentration. Refer to product container for lot specific information.

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Mueller Hinton Broth powder should appear homogeneous, free-flowing, and light beige, with a few dark specks, in color. The prepared media should appear clear, and very light amber in color; may have slight precipitate.

REFERENCES

1. Wood, G.L. and J.A. Washington. 1995. Antimicrobial Susceptibility Tests; dilution and disk diffusion methods. In Murray, P.R., et al. Manual of Clinical Microbiology, 7th ed. American Society for Microbiology, Washington, D.C.; 1327-1341.

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

3. Barry and Fay. 1973. Am. J. Clin. Pathol.; 50:196.

4. Bauer, A.W., W.M.M. Kirby, et al. 1966. Am. J. Clin. Pathol.; 45:493-496.

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

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

7. Methods for Dilution Antimicrobial Test for Bacteria that Grow Aerobically , 4th ed., M7-A5. 1997. Clinical Laboratory Standards Institute (CLSI - formerly NCCLS), Villanova, PA.

8. Mueller, J.H. and J. Hinton. 1941. A protein-free medium for primary isolation of the Gonococcus and Meningococcus. Proc. Soc. Exp. Diol. and Med.; 48:330-333.

9. Standard Disk Susceptibility Test, The Federal Register, September 30, 1972; 37(191):20527-20529.


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

061416gr