Figure 1
![Clinical diseases caused by non-tuberculous mycobacteria. Common and less common isolated NTM species are listed in an alphabetical order [8, 9, 10].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647088b271e4585e08a9f607/j_ahem-2021-0050_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251107%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251107T054823Z&X-Amz-Expires=3600&X-Amz-Signature=5e932f345ce6e01045993f4dd9f52be9bbe4366c211eabd5ed131f3975439268&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2
![Predisposing factors for non-tuberculous mycobacterial diseases [47, 50].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647088b271e4585e08a9f607/j_ahem-2021-0050_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251107%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251107T054823Z&X-Amz-Expires=3600&X-Amz-Signature=dc40da861c133029780ce37941c022b66be2daf7d942c34b6e1f96ce1990c7b2&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3
![MALDI-TOF spectra of protein extracts of Mycobacterium spp. Expanded view of MALDI-TOF mass spectra representing Mycobacterium spp. from Polish Collection of Microorganisms (PCM): (A) M. farcinogenes PCM 2220, (B) M. kansasii PCM 2584, (C) M. smegmatis PCM 494, (D) M. peregrinum PCM 639, (E) M. phlei PCM 654, (F) M. smegmatis PCM 657. Colonies grown on Löwenstein-Jensen agar were incubated at 37°C for 72 h. Spectra were acquired using extraction protocol according to El Khéchine et al. [67].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/647088b271e4585e08a9f607/j_ahem-2021-0050_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251107%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251107T054823Z&X-Amz-Expires=3600&X-Amz-Signature=4ff196256ec8a5fbe302a214ebcf4ca144e6884247d458593356809398252f83&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
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 |