M-Azide Broth Base

M-AZIDE BROTH BASE

PRODUCT SUMMARY AND EXPLANATION
Enterococci may be considered an essential part of the autochthonous microflora of humans and animals. Because of its wide distribution, Enterococci can also occur in different food commodities, especially those of animal origin. The most important feature of this genus is their high level of endemic antibiotic resistance. In bodies of water, the acceptable level of contamination is very low. In 2004, Enterococcus species took the place of fecal coliform as the new federal standard for water quality at public beaches. It is believed to provide a higher correlation than fecal coliforms with many of the human pathogens often found in sewage. M-Azide Broth was formulated by Slanetz, Bent and Bartely and is especially recommended for the enumeration of Enterococci from water samples and other specimens using membrane filter technique. In this technique, a measured volume of the watersample isfiltered through amembrane with a pore size small enough to retain the indicator bacteria to be counted. The membrane is then aseptically placed and incubated on a selective indicator medium (or sterile absorbent cotton pads saturated with the selective medium), so that the indicator bacteria grow into colonies on its upper surface.
For membrane filter technique, 2.2 ml medium is added per absorbent pad. Using this medium, Slanetz et al observed better recovery of pure cultures of Enterococcus faecalis by membrane filter technique than MPNtechnique.

PRINCIPLE
Tryptose, yeast extract provide essential growth nutrients. Dextrose and saccharose are the fermentable carbohydrates. Sodium azide is used as selective agent, which inhibits gram-negative bacteria. Mallmann et al reported that sodium azide exerts bacteriostatic effect on gram-negative bacteria allowing unrestricted growth of gram-positive cocci, particularly
Enterococci. TTC imparts pink to red colour to the colonies.

QUALITY CONTROL SPECIFICATIONS
Appearance of Powder : Cream to yellow homogeneous free flowing powder
Appearance of prepared medium : Light yellow coloured clear solution without any precipitate
pH (at 25°C) : 7.1±0.2