BacterTube™ Rapaport – Vasiliadis

The test medium is used to detect urease-producing microorganisms The selective medium is used for selective enrichment to promote the growth of Salmonella bacteria.
Code: 08044
Packaging: 50 tubes/ box or as per customer request.
Storage Conditions: 2–8°C.
Transportation: Ambient temperature.
Shelf Life: 6 months from the date of manufacture.

INTENDED USE

BacterTube™ Rapaport – Vasiliadis is a selective enrichment medium for Salmonella species from food and animal feed. This medium can also be used for direct enrichment of low-concentration samples.

PRINCIPLES

BacterTube™ Rapaport – Vasiliadis Salmonellae generally thrive in environments with slightly high osmotic pressure, cultured at a slightly low pH, and are resistant to malachite green when compared to other bacteria. These characteristics are exploited in this medium to selectively enrich Salmonellae.
Magnesium chloride is present in the medium to increase osmotic pressure. The natural sugars from Peptone from Soymeal provide essential growth nutrients and promote the growth of Salmonellae. The phosphate buffer in the medium maintains a stable pH. Sodium chloride helps maintain osmotic balance. Malachite green inhibits many Gram-positive bacteria, while selectively enriching Salmonellae. The relatively lower nutrient concentration also aids in selectively enriching Salmonellae.

Transfer 0.1 mL of the inoculum into a 10 mL prepared medium (1:100 dilution ratio).
The inoculum typically forms a pre-enrichment medium: Peptone buffer (TM 307).
Incubate at 35°C for 16-20 hours.
Perform isolation on selective media for Salmonella sp. using a streaking loop. Inoculate 0.1 mL of the pre-enrichment Peptone buffer into 10 mL of Rappaport – Vassiliadis medium and incubate at 41.5 ± 0.5°C for 21 – 27 hours. Then, streak onto confirmatory media, including XLD agar, and incubate at 35 ± 2°C. Check for growth after 18 – 24 hours of incubation.

RESULTS

Perform isolation on XLD agar and on a second selective isolation medium, using a streaking loop.
In the presence of characteristic colonies, carry out the necessary confirmatory tests.

BacterLab ensures the quality of each product batch by testing with ATCC reference strains.

Reference strains	Incubation conditions	Expected results
Salmonella typhimurium ATCC 14028	18 – 24 hours, 35 – 37^oC	Good growth, red colonies with a black center
Salmonella arizonae ATCC 13314		Good growth, red colonies with a black center
Pseudomonas aeruginosa ATCC 27833		Inhibition, red colonies
Escherichia coli ATCC 25922		Complete inhibition, yellow colonies