What is the purpose of potassium tellurite in tellurite medium?

Potassium tellurite plays a crucial role in tellurite medium primarily by inhibiting the growth of normal flora while allowing the selective isolation of specific pathogenic bacteria, particularly those from the genus Staphylococcus or Corynebacterium. Its mechanism involves the selective toxicity of potassium tellurite, which interferes with the cellular processes of many non-target bacteria, thereby suppressing their growth.

This selectivity is essential for laboratory diagnostics, as it allows for clearer identification and isolation of pathogens from a sample that may contain a vast number of different bacterial species. The ability of potassium tellurite to inhibit unwanted flora while facilitating the growth of certain pathogens makes it a valuable component in selective microbiological media.