Isolation and differentiation of Corynebacterium diphtheriae.
Hoyle Medium Base with the addition of 50ml laked blood and 3.5% potassium tellurite solution is a highly selective medium which allows the isolation and differentiation of Corynebacterium sp. Specimens are plated directly onto the surface of the medium without further streaking. Normally incubation at 35°C for 18 hours is sufficient for growth to occur, however in some cases up to 72 hours may be required. Differentiation of species type of Corynebacterium sp. may be determined by examination under a low powered binocular microscope. It should be noted that not all strains of Corynebacterium produce typical colonies on Hoyle Medium Base and it is advisable that other media, i.e. Loeffler Agar, be run in parallel and further biochemical tests be performed on suspected isolates.
