HEART INFUSION AGAR, MODIFIED

A liquid medium containing an infusion of meat was one of the first media used for the cultivation of bacteria. These infusion media need not be further supplemented by the addition of supplements in case of fastidious bacteria. Heart Infusion Agar, modified is used in the isolation and cultivation of diarrheagenic Escherichia coli in accordance with FDA BAM, 1998. E. coli is a Gram negative, facultatively anaerobic bacterium that is found as commensals in human intestine.
This medium is cited in BAM for primary screening in the conventional biochemical screening and identification of diarrheagenic Escherichia coli. Enrichment of the sample on BHI and TP broths is recommended as the first step in primary screening of diarrheagenic E. coli. This may induce the growth and proliferation of other members of Enterobacteriaceae including non-lactose fermenting strains of E. coli. Hence additional tests may need to be performed for isolation. Transfer suspicious colonies to TSI agar, Heart Infusion Agar, Modified slants, Tryptone Broth, Arabinose Broth, and Urea Broth and incubate for 20 hrs at 35?C. Organisms isolated on primary screening are processed for secondary screening and confirmed using genotypic, biochemical and serological reactions. On supplementation of blood, Heart Infusion Agar, modified can be used to study haemolytic reactions.

for isolation and cultivation of fastidious pathogenic microorganisms like Neisseria, Streptococci etc. and for con?rmation of diarrheagenic Escherichia coli in accordance with FDA BAM, 1998.