Directions
Dissolve 37g in 1 litre of distilled water. Mix well and distribute into final containers. Sterilise by autoclaving at 121ºC for 15 minutes.

Description
Heart Infusion Broth has been developed to give the same performance characteristics as Brain Heart Infusion (BHI) Broth. However, as bovine brain is a specified risk material, the exclusion of it from the Heart Infusion Broth means that the regulatory requirements when using it are lower.
The medium has been developed to give equivalent performance to Brain Heart Infusion but the exclusion of calf brain infusion means that Heart Infusion Broth carries a lower regulatory burden.

Simple additions may be made to the medium to make it suitable for the cultivation of yeasts and moulds and for use in blood culture.
A highly nutritious infusion medium recommended for the cultivation of streptococci, pneumococci, meningococci and other fastidious organisms.

Technique
Heart Infusion Broth can be supplemented with yeast extract, haemin and menadione to improve the growth of Bacteroides spp.¹A medium for blood culture can be prepared by adding 1g of agar per litre of Heart Infusion. Ensure that the agar is uniformly distributed in the sterile broth before dispensing into bottles. More conveniently, add 1 Agar Tablet (CM0049) to each 100ml of Heart Infusion and sterilise by autoclaving for 15 minutes at 121ºC. Cool to 60-70ºC and mix gently to ensure uniform distribution of the agar¹.

Supplements to improve the recovery of organisms from blood can be added before sterilisation or aseptically post-sterilisation. Co-enzyme 1 (NAD), penicillinase and p-amino benzoic acid are examples¹. The addition of anti-microbial agents such as cycloheximide and chloramphenicol also make this medium suitable for the cultivation of yeasts and moulds.

Storage conditions and Shelf life
The dehydrated medium should be stored at 10-30°C and used before the expiry date on the label.
Store the prepared medium in the dark below 20°C.

Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Straw coloured liquid

Quality control

Positive controls:	Expected results
Streptococcus pneumoniae ATCC® 6303 *	Turbid growth
Candida albicans ATCC 10231	Turbid growth
Negative control:
Uninoculated medium	No change

* This organism is available as a Culti-Loop®

Precautions
Heart Infusion Broth should only be used for in vitro diagnostic purposes.

References
1. Bridson, E.Y. (Ed) (1998), The Oxoid Manual, 8th Edition, Oxoid Ltd, UK, pp. 2-51.2-52.