Brain Heat Infusion Broth :Principle and Cultural characteristics

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Brain Heart Infusion Broth

Brain Heat Infusion Broth is highly nutritious and is recommended for the propagation of pathogenic cocci and other fastidious organisms associated with blood culture work and allied pathological investigations, as well as for Staphylococcus aureus enrichment.

Principle of Brain Heat Infusion Broth

Rosenow devised the original BHI by adding brain tissue to dextrose broth. Brain Heart Infusion Broth is a highly nutritious medium and is also well buffered to support the growth of wide variety of microorganisms. The ISO committee recently recommended this medium for the detection of Staphylococcus aureus. With the addition of desired additives, this medium can be used to cultivate a variety of bacteria. With the addition of 6.5 percent sodium chloride, it becomes selective for the isolation of various salt-tolerant bacteria such as Enterococci. BHI is also used to prepare inocula for antimicrobial susceptibility tests.

Composition of Brain Heat Infusion Broth

IngredientsGms / Litre
Peptic digest of animal tissue10.000
Calf brain, infusion (solids)12.500
Beef heart, infusion (solids)5.000
Dextrose2.000
Sodium chloride5.000
Disodium phosphate2.500
Final pH ( at 25°C)7.4±0.2
Composition of BHI

Preparation procedure of Brain Heat Infusion Broth

  • Dissolve 37 grams in 1000 mL of distilled water.
  • Dispense into bottles or tubes and sterilize for 15 minutes in an autoclave at 15 lbs pressure (121°C).
  • The medium should be used the same day it is prepared for the best results; otherwise, it should be boiled or steamed for a few minutes and then cooled before use.

Quality Control of Brain Heat Infusion Broth

AppearanceCream to yellow homogeneous free flowing powder
Color and Clarity of prepared mediumLight amber coloured, clear to slightly opalescent solution
ReactionReaction of 3.7% w/v aqueous solution at 25°C. pH : 7.4±0.2
pH7.20-7.60
Cultural ResponseCultural characteristics observed after an incubation at 35-37°C for 18-24 hours.
Brain Heart Infusion Broth
Brain Heart Infusion Broth

Cultural Response on Brain Heat Infusion Broth

OrganismInoculum
(CFU)
Growth
Neisseria meningitidis50-100luxuriant
Staphylococcus aureus50-100luxuriant
Streptococcus pyogenes50-100luxuriant
Streptococcus pneumoniae50-100luxuriant

Storage and Shelf Life

Store below 30°C in tightly closed container and the prepared medium between 2 – 8°C. Use before expiry date on the label.

Reference

  • Rosenow, 1919, J. Dental Res., 1:205.
  • Roseburg T. et al, 1944, J. Inf. Dis., 74:131.
  • Conant N.F., 1950, Diagnostic Procedures and Reagents, 3rd Ed., APHA, Inc., New York, p. 452.
  • MacFaddin J.F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. I, Williams and Wilkins, Baltimore.
  • International Organization for Standardization (ISO), 1983, Enumeration of Staphylococcus aureus, Draft ISO/DIS 6880.

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About the Author: Labweeks

KEUMENI DEFFE Arthur luciano is a medical laboratory technologist, community health advocate and currently a master student in tropical medicine and infectious disease.

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