AFB Culture (MGIT)

AFB denotes Acid-fast bacteria, also called acid-fast bacilli. These are a group of bacteria sharing the property of acid fastness, that is the physical ability to resist decolorization by acids during staining procedures. This unique feature serves as a distinguishing ability in classifying and detecting acid-fast bacteria like Mycobacteria.

MGIT is short for Mycobacteria Growth Indicator Tube. It is a liquid broth medium that is known to yield better recovery and faster growth of mycobacteria and a system that determines if AFB will grow in the presence of mycobacterium drugs or not.

Why get tested with AFB culture MGIT?

MGIT is a liquid broth medium that is known to yield better and faster growth of mycobacteria, the advantage is that the bacteria grow much faster and therefore help to determine whether or not AFB grows in the culture, and find out if it is susceptible to the TB drugs that are being tested.

What is a drug susceptibility test?
Drug susceptibility test (DST) or Antibiotic susceptibility testing (AST) is a widely-used technique for evaluating antibiotic resistance and determining the most effective antibiotic for treatment. This is achieved by observing the effect of a particular antibiotic on microbial growth. The treatment can be directed as per the knowledge of the microbe and its sensitivity to the drug.

What sample is required and what preparation is needed for this test?
A pure culture obtained from body fluids, sputum, bronchial alveolar lavage, cerebrospinal fluid (CSF), pus, tissue, biopsies, lymph nodes, abscess, urine is used for performing this test. There is no special preparation required before getting this test.

What are the types of drug-resistant TB?
Drug-resistant tuberculosis infection, caused by drug-resistant Mycobacterium tuberculosis (MTB) bacterium is divided into the following categories

• Multidrug-resistant or MDR-TB: MDR-TB is the TB infection caused by MTB that is resistant to the most potent drugs used in TB treatment – isoniazid and rifampin.
• Extensively drug-resistant or XDR-TB: XDR-TB is the TB infection caused by MTB that is resistant to most commonly used drugs used in TB treatment like isoniazid and rifampin, plus any fluoroquinolone as well as at least one of the three injectable second-line drugs (amikacin, kanamycin, and capreomycin)

What does MGIT stand for?
MGIT is short for Mycobacteria Growth Indicator Tube.