MUELLER HINTON AGAR

Technical Data #1247a / 2013.06.27

Mueller Hinton agar is a solid medium used for susceptibility testing of pathogens. Bauer et al. have recommanded this medium as routine methods for disk susceptibility testing. Disks impregnated with known amount of antibiotics are placed on the agar surface. Trimethoprim/sulfomethoxazole disk gives a satisfactory clear zone with Enterococcus faecalis ATCC 29212 if thymidine level is as low as possible

 


 

FORMULA
in grams per liter purified filtered water

Beef Extract

2,0

Acid Casein Hydrolysate

17,5

Starch

1,5

Agar

17,0

pH 7,3 +/- 0,1 25 C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8 C protected from direct light and dehydrated powder, in a dry place, in tightly-sealed containers at 2-25 C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 38 g of Mueller Hinton dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Sterilize at 121 C for 15 minutes. Cool to 45-50 C. Mix gently and dispense into sterile Petri dishes.


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Into a Mueller Hinton Broth with 4-5 similar colonies from an overnight growth, prepare a solution and adjust to 0,5 Mc Farland Standard.
  2. Following established procedures, inoculate plates by swabbing the inoculum on the surface three times.
  3. Place appropriate susceptibility disk on the surface and press gently.
  4. Incubate at 35 C for 24 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

NCCLS STANDARDS

Enterococcus faecalis

29212

meets NCCLS Standards

Escherichia coli

25922

meets NCCLS Standards

Staphylococcus aureus

25923

meets NCCLS Standards

Pseudomonas aeruginosa

27853

meets NCCLS Standards


LIMITATIONS OF METHOD
Disk diffusion testing with Mueller Hinton has been standardized with rapid growning microorganisms. This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Bauer, A.W., W.M.M. Kirby, J.C. Sherris, M. Turck. 1966 Antibiotic susceptibility testing by a standardized single disk method. Am. J. Clin. Pathol. 45:493-496
  2. D'Amato, R.F., L. Hochstein 1982 Evaluation of a rapid inoculum preparation method for agar disk diffusion susceptibility tests J. Clin. Microbiol. 15:282-285
  3. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American society for Microbiology.
  4. Munro. S., 1992 Disk diffusion susceptibility testing In; Clinical Microbiological Procedures Handbook. Hindler J., section ed; Isenberg HD ed. Washington D.C. American Society for Microbiology 5.1.1-5.1.30
  5. NCCLS 1990 Performance Standards for Antimicrobial Disk Susceptibility Tests. Approved Standard 4th ed. Document M2-A4 Vol.10, No.7
  6. NCCLS 1994 Performance Standards for Antimicrobial Susceptibility Testing 5th Informational Supplement Document M100-S5 Vol.14, No.16
  7. Pollock, H.M., A.L. Barry, T.L. Gavan, P.C. Fuchs, S. Hansen, C.L. Thornsberry, H.Frankel, S.B. Forsythe 1986 Selection of a Reference Lot of Mueller Hinton Agar J. Clin. Microbiol. 24:1-6


CATALOGUE NUMBERS

Dehydrated media 500 grams QB-39-3206
Prepared media    
Plates,100x15 mm 10/pkg 1247
Mono-Plates, 100x15 mm 10/pkg  
Plates, 150x15 mm 5/pkg 1569
Mueller Hinton Broth    
Tubes, 16x125 mm 10/pkg 2663

 


 

 

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