Collection, Storage & Transport of faecal sample

Collection of stool

1.      Stools samples should be collected in clean leak-proof containers without disinfectant or detergent residue and with tight-fitting, leak-proof lids.

2.      Unpreserved stool should be refrigerated, if possible, and processed within a maximum of 2 hours after collection.

3.      Specimens that cannot be cultured within 2 hours of collection should be placed in transport medium and refrigerated immediately.

Caution: Specimens should not be collected from bedpans, because the bed pans may contain residual disinfectant or other contaminants.

Transport media for fecal specimens

Media appropriate for the transport of fecal specimens that are suspected to contain Shigella, Vibrio cholerae, or Salmonella (including serotype Typhi) specimens are:

1.      Cary-Blair transport medium
High pH (8.4)
Medium of choice for transport and preservation of V. cholera
Cary-Blair transport medium can be used to transport many bacterial enteric pathogens, including Shigella, Salmonella, and Vibrio cholerae

2.      Amies’and Staurt’s transport media
Acceptable for Shigella and Salmonella (including ser. Typhi), but they are inferior to Cary-Blair for transport of V. cholerae.

3.      Alkaline peptone water
This medium may be used to transport V. cholerae, but this medium is inferior to Cary-Blair and should be used only when Cary-Blair medium is not available. Alkaline peptone water should not be used if subculture will be delayed more than 6 hours from the time of collection, because other organisms will overgrow vibrios after 6 hours.

4.      Buffered glycerol saline (BGS)
It’s a liquid medium which can be used for Shigella but this transport medium is unsuitable for transport of V. cholerae.

Rejection of fecal Specimens

Stool specimens are unacceptable if any of the following conditions apply;

1.      The information in the label does not match the information in the requisition

2.      The specimen has not been transported in the proper medium (information about media already provided in the blog post above)

3.      The quantity of specimen is insufficient for testing