Ann Clin Microbiol 2025;28(4):26. Drug susceptibility testing for Mycobacterium tuberculosis: a narrative review
| Category | Drug | Critical concentrations (μg/mL) by medium | |||
|---|---|---|---|---|---|
| LJ | Middlebrook 7H10 | Middlebrook 7H11 | MGIT | ||
| Drug-susceptible TB | |||||
| First-line drugs | Rifampicin | 40.0 | 0.5 | 1.0 | 0.5 |
| Isoniazid | 0.2 | 0.2 | 0.2 | 0.1 | |
| Ethambutola) | 2.0 | 5.0 | 7.5 | 5.0 | |
| Pyrazinamidea) | – | – | – | 100.0 | |
| MDR/RR-TB | |||||
| Group A | Levofloxacin | 2.0 | 1.0 | – | 1.0 |
| Moxifloxacin | 1.0 | 0.5 | 0.5 | 0.25 | |
| Moxifloxacin (CB) | – | 2.0 | – | 1.0 | |
| Bedaquiline | – | – | 0.25 | 1.0 | |
| Linezolid | – | 1.0 | 1.0 | 1.0 | |
| Group B | Clofazimine | – | – | – | 1.0 |
| Cycloserine/Terizidone | – | – | – | 16.0 | |
| Group C | Delamanidb) | – | – | 0.016 | 0.06 |
| Imipenem-cilastatin | – | – | – | – | |
| Meropenem | – | – | – | – | |
| Amikacin | 30.0 | 2.0 | – | 1.0 | |
| (or Streptomycin) | 4.0 | 2.0 | 2.0 | 1.0 | |
| Ethionamide | 40.0 | 5.0 | – | 5.0 | |
| Prothionamide | 40.0 | – | – | 2.5 | |
| PAS | – | – | – | – | |
a)Ethambutol and pyrazinamide are also classified as Group C agents for MDR/RR-TB regimens according to the World Health Organization (WHO) guidelines; b)Although delamanid is categorized as a Group C drug according to the WHO guidelines, it is classified as a Group A agent in the Korean guidelines for TB.
Abbreviations: LJ, Löwenstein-Jensen; MGIT, mycobacterial growth indicator tube; TB, tuberculosis; MDR/RRTB, multidrug-resistant/rifampicin-resistant TB; CB, critical breakpoint concentration; PAS, para-aminosalicylic acid.