Transport media in microbiology is a type of medium used to preserve and transport microorganisms from one location to another. These media typically contain nutrients and growth factors that support the survival of the microorganisms during transport.
What is transport media?
Transport media in microbiology are basically buffer solutions with carbohydrate, peptones, and other nutritional elements (but not growing factors) that are meant to keep bacteria healthy during transport without allowing them to multiply. The main goal of using the medium is to keep the sample as close as possible to how it was when it was first taken.
Transport media definition
Transport media in microbiology are specially formulated buffer solutions that contain carbohydrates, peptones, and other nutrients to protect the integrity of microorganisms during transport, without promoting their growth. The primary objective of using these media is to maintain the sample in as close to its original state as possible.
The purpose of transport media in microbiology is to safeguard a specimen and prevent excessive bacterial growth from the time of collection to the processing of the sample. The composition of the transport medium may vary depending on the type of organisms present in the sample. In general, transport media are categorized according to their consistency as semi-solid or liquid, and their applicability as viral or bacterial transport media.
Image 1: Transport media in microbiology
What's in Transport Media
Transport media only include buffers and salts and do not contain any nutrients such as nitrogen or carbon, or organic growth stimulants, in order to prevent the proliferation of microorganisms. Additionally, antibiotics and other compounds like glycerol may be utilized for transporting tissues for culture.
What can be stored in it?
Different types of samples may contain pathogens, but some may require transport media in order to process them in a timely manner. Examples include stool, urethral swabs, throat and nasal swabs, and samples for tissue culture. These transport media in microbiology are used to preserve the integrity of the sample and prevent the growth of microorganisms during transportation.
Transport media example
Here are a few instances of transportation mediums and their intended purpose:
Cary and Blair Medium: This is a liquid medium used to transport and store bacteria and other microorganisms, especially those that cause infections in the digestive tract. It has a combination of antibiotics and a buffer system that stop other microorganisms from growing and keep the pH stable while it is being shipped.
Stuart’s Transport Medium: Stuart’s Transport Medium is a liquid media used to move and store gram-negative bacteria, particularly those that cause enteric infections. It has bile salts, which stop gram-positive bacteria from growing, and lactose, which gives gram-negative bacteria energy.
Amies Transport Medium: Amies Transport Medium is a liquid used to move and store a wide range of microorganisms, such as bacteria, viruses, and fungi. It has a dry powder that needs to be mixed with water before it can be used. The powder has nutrients, like peptones, that help microorganisms stay alive during transport.
Amies Medium with Charcoal: Amies Transport Medium with Charcoal is a liquid medium used to move and store bacteria, viruses, and other microorganisms, especially those that cause respiratory infections. It has charcoal in it, which helps to get rid of toxins and keep the pH stable while being transported.
Buffered Glycerol Medium: Buffered Glycerol Transport Medium is half liquid and half solid. It is used to move and keep bacteria, especially ones that cause respiratory infections. It has glycerol, which keeps the bacteria alive by keeping them from losing water, and a buffer system, which keeps the pH stable while the bacteria are being moved.
VR Transport Medium: Venkatraman-Ramakrishnan medium is a another great transport media for vibrio cholerae. It is used to move stool samples that might have Vibrio cholerae in them. This medium keeps the bacteria alive while it is being moved to the lab.
Sachs’ buffered glycerol saline: Sachs’ buffered glycerol saline (SBGS) is a way to transport and store faeces, urine, and other clinical specimens so that bacteria that cause diseases, like cholera, can be found. It is a buffered solution of glycerol and saline that helps keep the bacteria alive while they are being moved to the lab.
The Viral Transport Medium: The Viral Transport Medium (VTM) is an effective tool for diagnosing viral infections. It can be used to preserve ocular, respiratory, and tissue samples. Fluid samples such as tracheal wash and peritoneal fluid should be submitted in their original form in sterile vials to prevent desiccation. If VTM is not available, swabs should be placed in sealed, sterile vials with a few drops of saline to prevent desiccation.
Anaerobic Transport Medium: Anaerobic Transport Medium (ATM) is a type of transport medium used to preserve and transport anaerobic microorganisms, such as bacteria and fungi, to the laboratory for further analysis. Anaerobic microorganisms are organisms that require a low oxygen environment to survive, and ATM provides the necessary conditions to keep these microorganisms alive during transport. ATM typically contains a variety of ingredients such as blood agar, thioglycolate broth, and antibiotics that help to inhibit the growth of other microorganisms and maintain the anaerobic environment.
FAQs on Transport media
Ice, Ice is not normally considered a transport medium, although it can be used to preserve and transport samples that require freezing temperatures to maintain their integrity throughout transport, such as biological samples.
Stuart’s Transport Medium preserves and transports various microorganisms. It helps preserve fastidious bacteria, which are hard to grow or have unique growth requirements.
Some of the bacteria that can be transported using Amies Transport Medium include: Neisseria gonorrhoeae, Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus ducreyi, and Listeria monocytogenes.
Some examples of transport media for vibrio cholerae include: Sachs’ buffered glycerol saline (SBGS), Alkaline peptone water (APW), Tryptic Soy Agar (TSA).
Amies Transport Medium is a type of transport medium that is used to keep bacteria and viruses alive and move them from one place to another.