Figure 1
Figure 2
Figure 3
Methods used for identification of non-tuberculous mycobacterial species [57, 63, 76]
| Culture-independent | Culture-dependent | ||
|---|---|---|---|
| Method | Limitation | Method | Limitation |
| Histology | Cell granulomatosis indistinguishable | Phenotypic methods | Time consuming, does not allow |
| from Tb | -Biochemical testing | identification of the newly described | |
| species | |||
| Smear microscopy | NTM not distinguishable from Mtb | Chemotaxonomical methods | Not available in all clinical laboratories |
| -HPLC of mycolic acids | |||
| Nucleic acid amplification test | Using for excluding Mtb | Direct probe hybridization assay | Limited number of species |
| -Commercial NAAT | |||
| Real-time PCR | Low sensitivity, limited range of species | Line probe assay | Limited number of species |
| – in-house methods | -Commercial test | ||
| Serological testing | Cross-reactivity | 16S DNA sequencing | Limited discriminatory power |
| Multigene sequencing | Expensive, not available in clinical | ||
| -Whole genome sequencing | laboratories | ||
| Highly trained staff | |||
| MALDI-TOF MS | Database content; quality of protein extracts | ||
Sources of non-tuberculous mycobacteria [4, 12, 41, 42, 44, 47, 48]
| Natural environment |
|---|
| Lakes, streams, rivers, ground water and seawater |
| Soil and dust from soil |
| Amoebae |
| Aquatic insects |
| Water plants and water distribution systems |
| Household/ Hospital environment |
| Plumbing systems |
| Tap water, shower heads, and faucets |
| Swimming pools, hot tubs, footbaths, hydrotherapy pools |
| Ice machines |
| Humidifiers |
| Dialysis centers |
| Heater-cooler units |
| Potting and garden soil |
| Aquarium water |
| Food products |
| Rainwater tanks and cooling towers |
| Indirect human-to-human transmission |