This biplate is used at Udder Health Systems Laboratory for selection and identification of both gram-positive and gram-negative organisms.
• The bright red agar portion of the biplate is prepared from a modified Columbia base agar with the addition of 5% defibrinated sheep blood, and esculin. This selective agar has been formulated to enhance the growth of gram-positive staphylococci, streptococci and enterococci bacteria while inhibiting the growth of all gram-negative organisms, such as Enterobacteriaceae and Pseudomonas. The addition of esculin enhances the capability of differentiating Streptococci. Certain Streptococci will hydrolyze esculin, causing a mild background blackening. This blackening differentiates E-streps from Streptococcus agalactiae which cannot split esculin. All suspect Streptococcus agalactiae organisms should be moved to our special Camp media for confirmation.
• The pink agar portion of the biplate is specialized media for the detection of gram-negative organisms. Since the antimicrobial agents in this agar inhibit the growth of gram-positive bacteria, the media focuses on the organisms’ ability to ferment lactose. This fermentation causes the bacterial colony to change to a pinkish color. Non-lactose fermenting colonies will remain colorless and opaque.
This is an indicator agar used for differentiating Streptococcus uberis from other E-streps in isolates from individual cow samples. The agar is also used as a selective agar in bedding samples for the isolation of Streptococcus uberis.