Selenite Broth

Selenite broth is used as a selective medium for the isolation of Salmonella species. Selenite Broth was originated by Leifson, while observing good recovery of Salmonella spp. and reduced growth of fecal coliforms. Selenite Broth is used as a selective enrichment for the cultivation of Salmonella spp. that may be present in small numbers and competing with intestinal flora. This medium must not be autoclaved. Once prepared it is steamed at 100°C for 30 minutes. There should be a very slight red precipitate. To minimise the risk of teratogenicity to workers, sodium selenite must be added separately to the medium. It has a pH of approximately 7.1.

Selenite broth contains:

Peptone 5g/l
Mannitol 4g/l
Di-sodium hydrogen phosphate 9.5g/l
Sodium di-hydrogen phosphate 10g/l
Sodium selenite (NaHSeO3) 4g/l

Leifson, E. 1939. New selenite selective enrichment medium for the isolation of typhoid and paratyphoid bacilli. Am. J. Hyg. 24:423-432.