AFB Susceptibility - Cycloserine Test

Acid Fastness Bacteria include a group of bacteria or eukaryotic cells that react to or resist the decolourisation effects rendered by acids during laboratory staining methods. This characteristic feature is observed in sub – cellular cells too. This mechanism helps in differentiating cells because the “acid – fast” mechanism is different for different species of cells. For instance, the Mycobacterium species that cause tuberculosis and leprosy exhibit its acid - fastness due to the high mycolic acid content in its cell walls which forms a staining pattern due to low absorption and high retention. The AFB Susceptibility Cycloserine test is a way of measuring or detecting the sensitivity in a given sample of sputum towards cycloserine. It helps in detecting the presence of drugs resistant to Tuberculosis or Leprosy.

The lab doesn’t suggest a set of strong preparatory measures that the patient needs to know beforehand. However, it is always beneficial to take precautions from your side and so, you should inform your doctor about the present medication you are going through if any. Also, notify your doctor about your allergies or underlying medical conditions you are not comfortable with. Informing your doctor about all these make it a two – way process since your doctor will instruct you accordingly and you won’t feel uncomfortable during the test which might, directly or indirectly, influence the results of your sputum test.

The test helps in detecting the presence of Mycobacterial organisms. “Negative” or “normal” tests indicate the absence of Mycobacterial organisms and there is nothing to worry about. “Positive” or “abnormal” tests show that the stain test is positive for one among the following organisms: M. leprae M. tuberclosis Non – tuberculosis bacteria or A set of other acid – fast bacteria.

The AFB Susceptibility Cycloserine test is performed by applying the Antibiotic Sensitivity method on a particular sputum sample. Varied concentrations of antimicrobial agents are isolated in a broth environment. The entire process is performed in a microtiter method with utmost convenience. The broth volume of about 0.05 to 0.1 ml is used for micro dilution techniques. Macro diluting methods use 1.0 ml of the total broth volume. Standard flasks are used for this method. Both the diluting tests are declared valid only if growth indicates positive control and the negative control shows arrested growth. A process synonymous to the above process, that is to Broth dilution method is Agar dilution. Antibiotic Sensitivity methods include other techniques like Disc Diffusion Method and E-test.