Drug-Resistant Tuberculosis Types and Their Treatment Regimens Using First-Line, Second-Line Injectable, Third-Line, Fluoroquinolones, Aminoglycosides, Cyclic Polypeptides, Novel and Repurposed Anti-Tuberculosis Drugs

Drug-Resistant Tuberculosis (DR-TB) causes high mortality and morbidity rates globally. DR-TB and COVID-19 pandemic are posing a major risk to global public health and economic security, and are jeopardizing efforts in the control, prevention and elimination of TB globally. Mycobacterium tuberculosis (MTB) has continued to evolve resistance to anti-TB drugs. Different types of DR-TB have been defined and they include; mono drug-resistant TB, Multi Drug-Resistant TB (MDR-TB), poly drug-resistant TB, pre-Extensively Drug-Resistant TB (pre-XDR TB), Extensively Drug-Resistant TB (XDR-TB), Extremely Drug-Resistant TB (XXDR-TB), and Totally Drug-Resistant TB (TDR-TB). DR-TB is caused by several factors which include: non-adherence, poor compliance, low efficacy anti-TB drugs, delayed diagnosis, interrupted supply, stock-outs, inadequate infection control, HIV co-infection, spontaneous mutations, and chromosomal replication errors. Global TB targets have gone off-track and years of progress reversed due to DR-TB and the COVID-19 pandemic. Treatment failure, death and costs incurred are higher among patients suffering from DR-TB than among those with susceptible TB. For this reason, susceptible TB needs to be diagnosed quickly and treated effectively to prevent its progression to DR-TB. Treatment for susceptible TB requires the use of first-line anti-TB drugs; rifampicin, isoniazid, pyrazinamide, and ethambutol. While DR-TB is treated using the second- and third-line anti-TB drugs. Effective treatment of TB is dependent on: prompt and accurate diagnosis of TB and recognition of drug-resistance; adherence to treatment; robust contact tracing and prophylactic treatment of TB contacts; and screening for TB infection in high-risk groups.