Vibrio Parahaemolyticus Sucrose HiVeg™ Agar

Principle and Interpretation

This medium is prepared by using vegetable peptones in place of animal based peptones which makes the medium free of BSE/TSE risks. Vibrio Parahaemolyticus Sucrose HiVeg Agar is the modification of Vibrio Parahaemolyticus Sucrose Agar (VPSA) which is recommended by APHA (1) for isolating and enumerating Vibrio parahaemolyticus from sea foods. It is a differential medium (and also selective to some extent) which distinguishes Vibrio parahaemolyticus from other marine Vibrios species.

Suspected seafood sample when diluted and blended with sterile HiVeg Peptone Tween Salt Diluent (prepared by dissolving 1.0gm of HiVeg Peptone and 10.0gm of Tween 80 in 1 litre of distilled water and autoclaved at 121°C for 15 mins), is filtered through HGMF using sterile diluent as a carrier. HGMF is then aseptically transferred to the Tryptone Soya HiVeg Agar w/ Magnesium Sulphate (TSAMS) plates and incubated for 4 hours at 35°C. HGMF is then transferred from TSAMS to the dry VPS HiVeg Agar plate and incubated for 18 - 20 hours at 42°C.

HiVeg hydrolysate No. 1, HiVeg hydrolysate and yeast extract provide the necessary nitrogen compounds, growth factors and vitamin B complex for the growth of Vibrio parahaemolyticus. Sucrose is the fermentable carbohydrate. Bromo thymol blue is the pH indicator. Synthetic detergent No. 1 inhibits the contaminating gram-positive bacteria. High salt content and alkaline pH of the medium meet the requirement of marine Vibrio and facilitates easy recovery of the organism respectively. Vibrio parahaemolyticus ferment sucrose and forms green to blue colonies.