Brucella Blood Agar (BBA)

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Introduction

Brucella Blood Agar (commonly notated as BBA or BRU) is a non-selective agar medium used for isolation, quantitation, and partial identification of fastidious anaerobes. This agar was originally developed for the isolation of Brucella spp. from potentially contaminated materials but has since been found to be useful for use in clinical specimens involving strict anaerobes. This agar is typically supplemented with Hemin and Vitamin K1.

The medium contains casein enzymic hydrolysate, peptide digest of animal tissue, and yeast extract as its main source of carbon, nitrogen, and growth nutrients. Sodium bisulfite lowers the redox potential to a range suitable for anaerobes. Sheep blood provides additional nutrients and allows the differentiation between hemolytic organisms by detecting hemolytic reactions. Sodium chloride is a source of essential electrolytes and maintains osmotic equilibrium.  Hemin and Vitamin K1 have been shown to support the growth of more strict anaerobes such as Bacteroides and Clostridium spp. Agar is used as the solidifying agent. 

Reconstitution

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Formula may be adjusted / supplemented to meet performance criteria. 

  1. Suspend all ingredients EXCEPT Hemin, Vitamin K1, and defibrinated sheep blood in distilled water. Heat to dissolve the medium completely.
  2. Sterilize media by autoclaving at 121ºC for 15 minutes. 
  3. Cool media to 45-50ºC and aseptically add sterile defibrinated sheep blood. 
  4. Aseptically add sterile Vitamin K1 and Hemin to the media and mix well to ensure thurough homogenization before pouring into sterile petri plates.   

Appearance: Bright red to dark red agar

pH: 7.2 ± 0.2

Storage

Media is both light and temperature sensitive. Store plates away from direct light at 2-8ºC. Plates may be used for one week when stored in a clean sterile area. Media should not be used if any signs of deterioration, hemolysis, contamination, and/or expiration date has passed.  

Sterilize all biohazard waste before disposal.


References 

[1] BD Brucella Blood Agar with Hemin and Vitamin K1. BD, Sep 2011. http://www.bd.com/resource.aspx?IDX=9009

[2] Brucella Agar with Hemin and Vitamin K (H & K). Hardy Diagnostics, 18 Oct. 2018, http://catalog.hardydiagnostics.com/cp_prod/content/hugo/brucellaagarhk.htm.

[3] Brucella Agar (w/ 5% Sheep Blood). Thermo FischerRemel,  18 Mar. 2018, https://assets.thermofisher.com/TFS-Assets/LSG/manuals/IFU1252.pdf

[4] Brucella Vitamin K1 Blood Agar Base. Himedia. Technical Data. Feb. 2015.     http://www.himedialabs.com/TD/M823.pdf