What is the purpose of potassium tellurite in tellurite medium?
Potassium tellurite acts as a selective agent and has inhibitory activity against most gram-positive and gram-negative bacteria except Corynebacterium species. C. diphtheriae reduces potassium tellurite to tellurium and thereby produce gray-black coloured colonies.
What type of media is Tellurite Agar?
Serum Tellurite Agar is a selective and differential medium primarily used for the isolation and detection of Corynebacterium diphtheriae. The nutrients in Serum Tellurite Agar are supplied by Proteose Peptone No. 3, which provides growth factors such as nitrogen, carbon, sulfur, and trace ingredients.
Which selective medium is used for isolation of Corynebacterium diphtheriae?
BD Tellurite Agar (Hoyle) is a partially selective and differential medium for the isolation of Corynebacterium diphtheriae from clinical specimens.
What is tinsdale agar?
Tinsdale Agar is used for the primary isolation and identification of Corynebacterium diptheriae. The medium differentiates between C. diphtheriae and the diphtheroids found in the upper respiratory tract.
Which color is taken by Corynebacterium Diphtheriae after Gram staining?
Corynebacterium Infections In a typical Gram stain these bacteria appear as V-in Y-shaped arrangements or in clumps that resemble Chinese letters. Corynebacteria are nonmotile, catalase positive, aerobic, and contain metachromatic granules when stained with methylene blue.
What makes Baird Parker Agar selective?
Publisher Summary. Baird–parker agar is a selective medium for the enumeration of Staphylococcus aureus in foods and this was first reported by Baird–Parker. It is widely recommended by national and international bodies. Selectivity is attained with potassium tellurite and lithium chloride.
What is Baird Parker medium?
Baird-Parker agar is a type of agar used for the selective isolation of gram-positive Staphylococci species. It contains lithium chloride and tellurite to inhibit the growth of alternative microbial flora, while the included pyruvate and glycine promote the growth of Staphylococci.
Why is potassium tellurite used as a selective medium?
Potassium tellurite along with agar may be used as a component of a selective medium for growth of bacteria. Use of potassium tellurite for testing the survival and viability of Pseudomonas pseudoalcaligenes KF707 in soil microcosms contaminated with polychlorinated biphenyls.
Which is more toxic tellurium or tellurate 2−?
The tellurites (TeO3) 2− are the most toxic compared with tellurates (TeO 4) 2−, or elemental tellurium. Only a few cases of nonoccupational poisoning to tellurium have been reported so far, and toxic effects are rare. Severe poisoning results in respiratory depression and circulatory collapse.
What can tellurite be used for in biochemistry?
A selective tellurite medium, such as Hoyle’s agar, and Tinsdale agar are very useful in the first step of identification of potentially toxigenic Corynebacterium species (see Section Characteristics of the Genus ). Identification of suspected isolates usually relies on Gram staining and biochemical reactions.
What kind of bacteria is found in tellurite?
most gram-positive and gram-negative bacteria except Corynebacterium species.C.diphtheriae reduces potassium tellurite to tellurium and thereby produce gray-black coloured colonies. Throat or nasal swab is directly inoculated and streakedon this agar medium.