K.A.A. Confirmatory Agar 1027 Condalab

KAA Confirmatory Agar (Kanamycin, Aesculin, Azide) is a selective medium used in the isolation and confirmation of intestinal enterococci in foods. KAA Confirmatory Agar can also confirm positives from KAA Presumptive Broth (Cat. CL-1209) tubes. Kanamycin, Sodium azide, and Sodium citrate have a great inhibitory effect on the bacterial flora as they inhibit the growth of Gram-positive and Gram-negative bacteria. The medium is highly selective for esculin-hydrolysing enterococci. Esculin and Ferric Ammonium citrate are esculin indicators which detect the esculin-hydrolysing bacteria. They hydrolyse the esculin to give glucose and esculetin. These microorganisms present black zones around the colonies from the reaction of the resulting esculetin with the iron ions.

Tryptone provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group essential for bacterial growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bacteriological agar is the solidifying agent. The presence of intestinal enterococci is an indicator for faecal contamination, especially when the contamination occurred long ago and the less resistant coliform bacteria, including Escherichia coli, are already dead when the analysis is carried out. Intestinal enterococci grow forming small, translucent colonies surrounded by a black halo. This medium is recommended by CeNAN for food and drinks analysis.