UREA AGAR SLANT (10 Slants)

Urea Agar Slant is a selective medium used to identify bacteria with urease activity. It is especially useful for identifying the rapidly urease-positive Proteus species and for the identification of slower urease-producing members of the Enterobacteriaceae. The medium is also useful for studying urease activity in other gram-negative organisms like Pseudomonas, Pasteurella and Brucella and in some yeasts.
It contains a peptic digest of animal tissue which supplies the necessary nutrients for growth of the microbes and dextrose as a source of energy. The sodium chloride maintains the osmotic balance and the phosphates provide buffering action. Urea acts as the substrate for urease activity. Organisms that produce urease hydrolyze urea and release ammonia, thereby increasing the pH of the medium. Phenol red detects this alkaline shift through a visible colour change from orange to pink.
The reduced peptone and buffering capacity of the medium makes it possible to detect lower levels of urease activity. A urease-free medium may serve as a negative control to detect the false positive reactions. Prolonged incubation may produce alkaline reactions due to protein utilization, so results should be interpreted carefully.

Detects urease production through urea hydrolysis and a characteristic colour change, aiding differentiation of urease-positive Gram-negative bacteria.