Amies Transport with Charcoal

Amies developed his formula (1967) with charcoal upon proving that Neisseria gonorrhoeae increased its survival rate when charcoal swabs were used. Amies solved the problem of charcoal removal from the swabs by incorporating charcoal into the formulation.

In the formulation, charcoal neutralizes fatty acids that are toxic to microorganisms. The chloride salts supply essential electrolytes for transport and osmotic balance. Phosphates act as a buffer system. Sodium thioglycollate suppresses oxidative changes and provides a reduced environment.

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

Preparation

Suspend 23.2 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. Dispense into tubes and sterilize in autoclave at 121 °C for 15 minutes. Maintain a homogeneous mixture of the charcoal throughout the medium by inverting the tubes as they cool.

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.

The container of this product may suffer deformation due to the high oxygen adsorption capacity of the activated charcoal contained in the formula.

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

• Amies C.R. (1967) "A Modified Formula for the Preparation of Stuart's Transport Medium". Can. J. Public Health 58: 296-300.
• 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.