Stuart Transport Medium

A Stuart Transport Medium is required for the preservation and transporting of Neisseria species and other mycoplasma organisms from the center to the laboratory. Stuart Transport Media, invented by Dr. R.D Stuart, was the first media made for transporting clinical swab samples. It is typically used in various medical and clinical settings for the collection and transportation of samples for testing. Twenty years after the presentation of Stuart’s medium, Cary and Blair changed it by supplanting sodium glycerophosphate with inorganic phosphate and raising the pH to 8.4. This change expanded the medium’s capacity to help the feasibility of intestinal microscopic organisms, like salmonella and shigella, in fecal examples.

Principle Of Stuart Transport Medium

This medium is a chemically defined, semisolid, non-nutrient medium that prevents microbial proliferation. Because of this composition, the medium ensures that the microorganisms present can survive for a sufficiently long period. The medium provides an adequate degree of anaerobiosis which can be monitored using the redox indicator methylene blue. Prepared sterile medium will undergo a slight degree of oxidation at the upper periphery of the medium, however, if the tube or vial exhibits a distinct blue color throughout the medium, it should be discarded. Calcium chloride along with sodium glycerophosphate acts as a good buffering agent and also maintains osmotic equilibrium in the medium.

Composition Of Stuart Transport Medium

IngredientsGms / Litre
1. Sodium glycerophosphate10.000
2. Sodium thioglycollate1.000
3. Calcium chloride0.100
4. Methylene blue0.002
5. Agar3.000
6. Final pH ( at 25°C)7.4±0.2
Composition Of Stuart Transport Medium

Direction Of Stuart Transport Medium

  1. Suspend 14.1 grams in 1000 ml double distilled water.
  2. Heat to boiling to dissolve the medium completely.
  3. Dispense into tubes with screw caps to give a depth of approximately 7 cm.
  4. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes and after sterilization tighten the caps.
  5. Cool the tubes immediately in an upright position. Care should be taken that the water is free from chlorine.

Stuart Transport Medium PROCEDURE

  • Prepare swabs by rolling absorbent cotton wool on wooden sticks.
  • Boil the swabs in a phosphate buffer solution of the following composition
IngredientsGms / 100ml
Disodium hydrogen phosphate0.81
Potassium dihydrogen phosphate0.18
Distilled water100ml
Final pH7.4
  • Immediately dip the swabs into a 1% suspension of charcoal (pharmaceutical grade).
  • Place in cotton-wool plugged test tubes and sterilize in the autoclave at 121 C for 15 minutes.
  • Dry at 100oC to remove any excess moisture.

Stuart Transport Medium TRANSPORTation

  • Obtain a specimen with a sterile swab. Insert specimen swab(s) into the upper third of the medium in the transport container.
  • Cut with sterile scissors or break off the protruding portion of the swab stick. Tightly screw the lid on the bottle or vial.
  • Label the bottle or vial and send it to the laboratory with minimum delay. Specimens may be refrigerated until ready for shipment.
  • Submit to the laboratory within 24 hours for culture and analysis.

Stuart Transport Medium Result

  • Survival of bacteria in a transport medium depends on many factors including the type and concentration of bacteria in the specimen, the formulation of the transport medium, the temperature and duration of transport, and inoculation to appropriate culture media within 24 hours.
  • Optimal growth and typical morphology can only be expected following direct inoculation and appropriate cultivation.

Stuart Transport Medium Storage

Store the sealed bottle containing the dehydrated medium at 4 – 30°C. Once opened and recapped, place the container in a low-humidity environment at the same storage temperature. Protect from moisture and light.

Stuart Transport Medium Expiration

Refer to the expiration date stamped on the receptacle. The dehydrated medium should be discarded if not free-flowing, or if the appearance has changed from the original color. Expiry applies to the medium in its intact container when stored as directed.

Stuart Transport Medium Application

Stuart Transport Media is primarily used for the transport and maintenance of all types of clinical samples. It was initially designed by Dr. R.D. Stuart for studying Gonococci, and later on, the medium was modified for the transportation of gonococcal specimens for culturing.

The medium is non-nutritional, meaning it maintains the viability of organisms without promoting significant multiplication. This is particularly useful for preserving specimens containing Neisseria species and other fastidious organisms during transportation. The reducing agent Sodium thioglycollate in Stuart medium also allows for the transport of anaerobic bacteria by creating a reduced environment that improves the recovery of these organisms.

In terms of specific applications, the Liquid Stuart swab collection system is available in various sizes for multiple applications, including rapid strep A antigen tests and aerobic culture. Regular-size swabs are typically used for throat, vaginal, wound, and skin samples. Mini-tip size swabs are typically used for pediatric sampling, ear, nose, throat, eye, and male urethral swab sampling.

Limitations and Alternatives to Stuart Transport Media

The limitations of Stuart Transport Media include that specimens taken from transport media will not exhibit the optimal or comparative growth as expected from direct inoculation and cultivation.

Cary-Blair and Amies Transport Media are alternatives to Stuart Transport Media.

Cary-Blair transport medium is used for the transport of fecal specimens suspected of containing enteric pathogens, including Shigella, Salmonella, Vibrio cholerae, and Escherichia coli.

Amies transport medium is a widely used and effective semisolid medium for the transportation of swab specimens to the microbiology laboratory. Placing swabs in a moist container or transport medium prevents drying and the death of bacteria.

Stuart Transport Media is used for transporting specimens suspected of having gonococci and for transporting throat, wound, and skin swabs that may contain fastidious organisms.

Stuart Transport Media Advantage

The benefits of using start transport media are multifaceted. From its ability to maintain the viability of diverse specimens to its versatility in accommodating various sample types, Stuart transport media stands out as a reliable choice for preserving microbiological materials.

Stuart Transport Media Alternative

Comparing start transport media with other transport media helps microbiologists make informed decisions. Understanding the strengths and weaknesses of alternatives provides valuable insights into choosing the most suitable medium for a given scenario.

Can I use Stuart Transport Medium for any type of specimen?

While STM is versatile, it’s essential to check its compatibility with specific specimens to ensure optimal preservation.

Are there any specific storage requirements for Stuart Transport Media?

Yes, maintaining recommended storage conditions, including temperature and light exposure, is crucial for the longevity of Stuart Transport Media.

How does Stuart Transport Media compare to other transport media?

Stuart Transport Media has unique advantages, but its comparison with alternative media depends on the nature of the specimens and the intended use.

Can Stuart Transport Media be used for long-distance transportation of specimens?

Yes, Stuart Transport Media is designed for preserving specimens during transit, including long-distance transportation.

Are there any ongoing research projects related to the development of Stuart Transport Media?

Yes, ongoing research aims to improve STM formulations, extending their shelf life and enhancing compatibility with a broader range of specimens.

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