Cary-Blair Medium

Cary-Blair Medium has a low nutrient content and a phosphate buffer, together with the sodium thioglycollate, that inhibit the massive growth of strains such as Escherichia coli and Klebsiella aerogenes. Agar No. 2 is the solidifying agent.

Due to its high pH, it minimizes the bacterial destruction due to the formation of acid.

Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.

Preparation

Suspend 13.2 grams of the medium in one liter of distilled water. Mix well. Heat with frequent agitation and boil until completely dissolved. Dispense into screw-capped test tubes and place in flowing steam for 15 minutes. Allow to cool at room temperature and tighten the caps to avoid water loss.

Instructions for use

1. Swab the area, ensuring to cover an adequate surface.
2. Allow the swab to remain in contact with the surface for 10-30 seconds to absorb the microorganisms.
3. Carefully remove the swab and immediately place it into the sterile transport medium. Seal the container properly to avoid any potential contamination.
4. Send the sample to the laboratory as quickly as possible to ensure the integrity of the microorganisms.

The survival of bacteria in a transport medium depends on various factors such as bacteria type and concentration in the specimen, transport medium formulation, and transport temperature and duration. Optimal growth and typical morphology can only be expected if direct inoculation and appropriate cultivation are followed.

Delays in sending the sample will result in a gradual reduction in bacterial viability.

• Cary, S.G. and E.B. Blair 1964. New transport medium for shipment of clinical specimens. J. Bacteriol.
• Cary, S.G., M.S. Mathew, M.H. Fusillo, and C. Hasking 1965. Survival of Shigella and Salmonella in a new transport medium. Am. J. Clin. Path.
• García Sánchez, J. E., Gómez-Lus Centelles, M. L., Rodríguez López, F. C., Torreblanca Gil, A., & Piédrola de Angulo, G. (1993). Recogida, transporte y conservación de muestras. Procedimientos en microbiología clínica: Recomendaciones de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica.