A patient will be diagnosed with drug-resistant tuberculosis if tubercle bacilli can be isolated from the sputum of a patient with tuberculosis and if this tubercle bacilli is found to grow in the presence of one or more anti-tuberculosis drugs by in vitro testing. This means that this patient is treated for TB with one or more anti-TB drugs that no longer work to kill the TB bacilli and needs to be treated with a second-line drug that is not commonly used. Drug resistance includes the following four types: 1. mono-resistant: resistant to only one anti-TB drug. 2. multi-resistant: resistant to one anti-TB drug. Multidrug resistance: resistance to more than one anti-TB drug, except for resistance to both isoniazid and rifampin. Since isoniazid and rifampin are the two most important drugs among the first-line anti-tuberculosis drugs for killing tuberculosis bacteria, if the results of drug resistance tests reveal that these two drugs are not yet resistant at the same time, the degree of drug resistance is relatively mild and first-line drug therapy can still be considered. 3. Multidrug resistance: Resistance to at least both isoniazid and rifampin. In this case, it is necessary to change to second-line anti-tuberculosis drugs for treatment. 4. Extensive drug resistance: In addition to resistance to isoniazid and rifampin, resistance to any one of the fluoroquinolones and at least one of the three second-line anti-tuberculosis drug injections (kanamycin and butamycin, capreomycin).