Which agar is best to use for identifying and growing L.monocytogenes

[redfox]

I need to grow up Listeria monocytogenes and have been instructed to use Tryptone Soya Agar as the growth medium, however I would have thought Heart Brain infusion would be better. Can anyone please tell me how I must decide which is best? Should I not use HIB cos it would grow absolutely everything and TSA is more selective? Will TSA grow ALL the listeria present?

 

Cheers:)

[Genecks]

you might like this: http://www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/UCM071400

 

Also, if you're inoculating something, then you're using sterile technique. Doing that prevents other junk from growing on your agar.

 

I think TSA would be more selective. The BHIA probably would have dextrose added to it, thus different bacteria could more readily access the dextrose for growth.

Edited July 22, 2010 by Genecks

[CharonY]

As the names imply, none of the mentioned media are truly limiting. Many usual contaminants (e.g. skin bacteria) proliferate very quickly on BHI, though. Also the risk of enriching pathogenic bacteria is higher there.

If you got a pure culture my choice would be use something more selective like Listeria enrichment broth. Overall tryptic soy broth is an acceptable choice, though.