B.D.G – BROTH HAJNA

Examination of water for the presence of marker groups such as enteric bacilli is one of the most common tests in a microbiology laboratory, partly because of the relative ease and speed with which these tests can be accomplished. Where it is claimed that drinking water has been processed for safety, the finding of such organism demonstrates a failure of the process. It is a valuable bacterial indicator for determining the extent of fecal contamination of recreational surface waters or drinking water. B.D.G.-Broth, Hajna (Buffered Deoxycholate Glucose Broth) is a selective enrichment or presumptive test medium used for the detection of all enteric bacilli in drinking water.
This medium is prepared according to the formula of Hajna and Damon. These authors reported a higher number of positive coliform findings from water and food samples using this media than with the use of standard methods media (Lactose Broth, etc.) B.D.G. Broth supports excellent growth of gram-negative enteric bacilli other than coliforms and may be used for the detection of lactose non-fermenting organisms.
While testing treated water, tubes showing no gas and very little or no growth are considered as negative. Tubes with growth are sub cultured on MacConkey Agar, SS Agar or Bismuth Sulphite Agar and suspected cultures are differentiated and identified. Authors reported recovery of a number of organism including Proteus from water samples showing growth but no gas in the presumptive medium. B.D.G. Broth contains sodium deoxycholate, which inhibits the development of spore formers and other gram-positive organism without affecting growth of coliform organisms and gram negative bacilli. For sample checking it was suggested that 10 ml of the medium should be used for sample volume of 1 ml or less. For the examination of larger amounts of water, the medium should be prepared in multiple strength. For example, 10 ml of the inoculum is added to 10 ml of double strength medium. Tubes showing gas formation following incubation at 35-37?C are transferred for confirmation. Hajna also recommended the use of BDG Broth for the performance of the Methyl Red test and Voges Proskaur test.

for the detection of enteric bacilli from food and in treated drinking water