Tuberculosis (TB)

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What is TB?

Figure 1

Tuberculosis (TB) is a bacterial disease which usually affects the lungs. In many cases it is symptomless (latent TB), but can progress to active disease which kills around half of those affected if left untreated.

Figure 2

Drug resistant TB

Myobacterium tuberculosis divides more slowly than most bacteria, making development of antibiotic resistance more likely (Figure 3). In addition, the mycolic acids in its cell wall limit the effectiveness of some antibiotics.

Figure 3

Figure 4

What are the symptoms?

Figure 5: Symptoms for TB.

How can it be treated?

Active TB is treated by taking several antibiotics for six to nine months. The four drugs shown in Figure 6 are commonly used first line drugs in treatment regimes.

Figure 6: First line TB drugs.

Tuberculosis that is resistant to first line drugs (Figure 6) must be treated with second line drugs (Figure 7). These can include drugs that are usually less effective, which have toxic side effects, or which are unavailable in developing countries. Streptomycin was formerly considered a first line drug, but is now used less due to increased cases of resistance to its effects.

Figure 7: Second line TB drugs.

Figure 8: License