Môi trường vi sinh Modified Semi-Solid Rappaport-Vassiliadis Agar (MSRV)
Modified Semi-Solid Rappaport-Vassiliadis Agar (MSRV) is a selective medium historically used for the isolation of Salmonella in chocolate and other food products. It is also widely used in animal health: in particular with mammals, poultry and in animal production facilities. It is also recommended for us in the detection of motile Salmonellae in animal fecal matter and in environmental samples in the context of primary animal production.
This medium is not recommended for immobile Salmonellae (Salmonella Gallinarum et Pullorum)
Principles and uses
Modified Semisolid Rappaport Vassiliadis Medium (MSRV) is a selective medium used for the rapid detection of motile Salmonella spp.
Is a modification of Rappaport Vassiliadis enrichment broth for detecting motile Salmonella spp in feces, food products and environmental samples. In this medium the main detection is based on the motility and ability of Salmonella to migrate through selective medium ahead of competing motile microorganism, therefore producing opaque halos of growth.
The mobility of other microorganisms is inhibited by selective mediums (such as magnesium chloride, malachite green oxalate and novobiocin) as well as by the temperature of incubation at 42 °C. Tryptose and acid casein peptone provide nitrogen, vitamins, minerals and amino acids essential for growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Magnesium chloride and malachite green oxalate are inhibitory to organisms other than Salmonella spp. Novobiocin is a selective agent that inhibits gram positive bacteria and avoids the development of Proteus. This medium is not suitable for the detection of non motile strains of Salmonella whose of which their presence is very low (= 1 %). It is recommended to conduct serological and biochemical tests for Salmonella species confirmation.
Preparation
Suspend 31,6 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. AVOID OVERHEATING. DO NOT AUTOCLAVE. Dispense into Petri plates.
