Mycobacterial culture

Mycobacterial  culture test is a special laboratory test that is  used to determine the mycobacterium tuberculosis  the causative bacterium of tuberculosis disease. Tuberculosis is commonly occurs in lungs and additionally can be found in any organ of  body. If no or inefficient treatment is done, tuberculosis may be a fatal disease. Today with modern treatment methods almost  % 100 of tuberculosis patients can be cured.

Why/when  the tuberculosis culture is performed ?

Mycobacterial culture test is performed to determine if patient has active tuberculosis symptoms. Also can be done to see the  efficiency of tuberculosis treatment.

Tuberculosis Culture Sample Collection

Tuberculosis infection may occur in any part of the body, if it is in any tissue or body fluid your doctor will perform the sample collection but if infection is in your lungs or kidneys you will have a role in sample collection for a few days.

mycobacterium culture

Mycobacterial culture in Sputum:

If your doctor thinks you have tuberculosis in lungs a sputum culture will be done to identify mycobacterium tuberculosis. You’ll be given 3 or 5 sterile sample cups for sputum collection. Your doctor requests you to collect samples for 3-5 days. Before giving the sample mouthwash with water may be helpful. You will need to cough strong and spit the material that comes from your lungs. Only spittle sample is not proper, mycobacterial culture needs the sputum from your lungs to identify the bacteria.

Mycobacterial culture in urine:

Tuberculosis infection may occur in kidneys and you would need to give urine sample for this test. You doctor may request  urine sample  in 3 or 5 consecutive days. First morning urine may be more  accurate for determining mycobacterium tuberculosis.

Which samples can be used for Mycobacterial Culture ?

  • Sputum
  • Bronchoalveolar lavage (BAL)
  • Urine
  • Gastric juice
  • Cerebrospinal fluid
  • Synovial fluid
  • Pericardial fluid
  • Pleural effusion
  • Tissue samples
  • Blood
  • Bone marrow
  • Abscess drainage
  • Stool

How the Tuberculosis Culture is performed ?

Personal protective equipment must be used. Gloves, mask, laboratory gowns, protective glasses, biological safety cabinets etc.

Decontamination is done to the samples except the sterile body fluids. Purpose of this process is to eliminate the microorganisms  other than  mycobacterium tuberculosis.

After decontamination process inoculation is done from the sediment. Special culture media is used  for mycobacterium tuberculosis growth.

Inoculated culture media will be waited in 37° , this is incubation  process. Incubation takes 6 weeks long for mycobacterial culture.

Acid-fast staining (AFS) is done from the sediment , acid-fast bacteria (AFB) means that the bacteria have resistant to acids during staining process. Mycobacterium tuberculosis  is a AFB and acid-fast staining is very useful to identify the bacteria and diagnose the infection. With analysing the AFS smears in microscope mycobacterium tuberculosis can be determined in a short time without waiting the incubation period.

How long  tuberculosis culture takes ?

Inoculated culture waits for 6 weeks in 37 °. Culture media is checked for everyday to see the  bacteria growth. If there is an bacteria growth some sample is taken from it and acid-fast staining is done. After identifying of the mycobacteria, antibiotic sensitivity test is done to find the effective antibiotics


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