The Brain Heart Infusion Agar: Definition, Usages, and Precautions

Eager to know what is the brain heart infusion agar? Then you are in the right place. A critical aspect of research in the field of microbiology is the study of microbial growth and cultivation. One of the most commonly used growth media is Brain Heart Infusion Agar, also known as BHI agar. This versatile medium is widely used in laboratories for the detection and detection of microorganisms, especially those that are difficult to culture. This article explores the uses and applications of BHI agar in detail, highlighting the unique properties that make it an indispensable tool for microbiologists in various disciplines. Go on scanning to have access to more information about BHI agar.

What is the Brain Heart Infusion Agar?

Brain Heart Infusion Agar is a general-purpose plating medium, which is used for the isolation, culture, and maintenance of a wide variety of adherent and non-adherent microorganisms.

In 1919, Rosenau developed an excellent medium for culturing streptococci using glucose broth enriched with brain tissue. Rosenau's formula was later modified by Hayden, who found that the addition of crushed marble allowed tooth pathogens to grow well. Our Current Formula Contains Calf Brain Injection Disodium phosphate replaced calcium carbonate instead of brain tissue.

Moreover, BHI Agar is a nutritious base that meets the growing needs of many species. Microorganisms such as bacteria, yeast, and fungi. BHI agar supplemented with (5-10%) defibrinated sheep blood is commonly used for the recovery of dimorphic fungi such as Histoplasma capsulatum and other pathogenic fungi such as Coccidioides immitis.

More selective formulations containing chloramphenicol and cycloheximide are also available to treat pathogenic fungi while inhibiting a wide variety of bacteria and saprophytic fungi. McDonough et al. It was shown that culture temperature may change the susceptibility of some pathogenic fungi to antibiotics. Therefore, it is recommended to use both antimicrobial and non-selective media for both primary isolates at 25°C and 35°C. 

Usages of the Brain Heart Infusion Agar

Brain Heart Infusion Agar (BHIA) is a nutrient-rich solid medium suitable for the cultivation of some fastidious bacterial, fungal, and yeast strains. It is used to culture various microorganisms such as streptococci, meningococci, and pneumococci. BHIA is recommended in standard practice for water testing and antimicrobial susceptibility testing. A nutrient-rich base of the bovine heart and calf brain infusion and a blend of peptones provides nitrogen, vitamins, minerals, and amino acids to support the growth of a wide variety of microorganisms.

In some cases, BHIA plates are also used for general susceptibility testing. However, this medium is not suitable for measuring hemolysis due to its high glucose concentration which can lead to erratic readings.  

Precautions of the Brain Heart Infusion Agar

The brain heart infusion agar is tested for compatibility with 7% v/v oxalic acid-treated horse blood, defibrinated horse blood, or defibrinated sheep blood. After 72 hours of incubation at 37°C, 25°C, or 4°C, there should be no evidence of lysis or darkening.

If this medium is used to isolate Histoplasma capsulatum, Coccidioides immitis, or other pathogenic fungi that may produce free infectious spores, extreme care should be taken to prevent the spread of infectious particles throughout the laboratory. You have to pay attention. Cultures should only be examined in closed, filtered-air cabinets.

In addition, This medium is not suitable for screening vancomycin-resistant enterococci (VRE). Better and better media are available for VRE screening. Ramel BHI with Brilliance VRE PO1226A or vancomycin RO1176.  

Conclusion:

In summary, Brain Heart Infusion Agar (BHIA) is a versatile and widely used medium that can support the growth of many different types of microorganisms. It is especially ideal for the isolation and cultivation of aerobic and anaerobic bacteria, fungi, and yeasts. The composition of BHIA is complex and nutritious, providing a wide range of carbon and nitrogen sources for microbial growth. Adding blood or serum may also promote the growth of certain microorganisms. In addition, it can be applied in various fields such as clinical diagnostics, industrial microbiology, and food testing. Its many windfalls make it a valuable medium for researchers and diagnostic laboratories worldwide.