Procedure for Culture Specimen Processing: Pus and other muco-purulent specimens

The procedure for processing pus and other muco-purulent specimens in TB cultures is as follows:

• If the specimen is thick or mucoid and less than 10 ml in volume, digest and decontaminate with N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) method similar to the procedure used for sputum specimens.
• If the specimen is not thick, it may be treated with 2-4% NaOH.
• The concentration of NaOH depends upon the contaminating bacteria expected to be present in the specimen.
• If the volume is over 10-12 ml, process only 10 ml or the first concentrate by centrifugation at 3000x g for 15-20 minutes.
  • In such a situation, if the specimen is thick, liquefy the specimen by adding a small quantity of NALC only (50-100 mg powder) and mix well.
• After the concentration step, resuspend the sediment in 5 ml sterile water, decontaminate with NaOH and concentrate again by centrifugation.
• Always resuspend the sediment (pellet) in buffer to reduce the pH.

Resources

• MGIT Procedure Manual, Mycobacteria Growth Indicator Tube (MGIT) Culture and Drug Susceptibility Demonstration Projects, FIND Training Manual.

Kindly provide your valuable feedback on the page to the link provided HERE