TABLE 1.
Comparison between M. tuberculosis and M. marinum
| Property | Description (reference[s])a
|
|
|---|---|---|
| M. tuberculosis | M. marinum | |
| Disease burden | 1.5 million people worldwide in 2018 (1) | Pulmonary NTM now surpass M. tuberculosis infections in the US, Canada, and western Europe (3); for M. marinum, the incidence rate in Denmark from 2010–2016 was 0.05–0.13 per 100,000 person-years (170) |
| Top 10 cause of mortality and leading cause from a single infectious agent (1) | ||
| Host range | Humans are the only reservoir for TB (171), with some sublineage specificity (172) | Amphibians, fish, and humans (173) |
| Suspected free-living amoebae (174) | ||
| Aerobe? | Obligate aerobe (175) | Suspected obligate aerobe (176) |
| Cell wall properties | Acid fast (177) | Acid fast (15) |
| Contains mycolic acids, PDIM, TDM, PGL, and SL1 (178) | Similar lipid composition; lacks the nonvirulent SL1 (178); unique LOS (179) | |
| Generation time (h) | 17–18 (180) | 4–6 (181) |
| Optimal temp (°C) | 37 (182) | 30 (181) |
| Biosafety level | 3 (183) | 2 (183) |
| Role of phagolysosome? | Resisted (184) | Similar to M. tuberculosis (185) |
| Role of TNF-α? | Increased susceptibility by anti-TNF treatment (186) | Higher incidence than TB during anti-TNF therapy (189) |
| Increased susceptibility in TNF KO (187) | Increased susceptibility in TNF receptor knockdown (190) | |
| Excessive TNF-α increases susceptibility (188) | Excessive TNF-α increases susceptibility (191) | |
| Susceptibility to adaptive immunity? | Controlled by polyfunctional CD4+ and CD8+ T cells (192) | Rag1 KO zebrafish are hypersusceptible (193) |
| Unknown what T-cell responses protect against infection (192) | IL-10 mutant zebrafish resist M. marinum infection via interferon gamma (194) | |
| Granuloma formation | Forms necrotic granulomas (46) | Forms necrotic granulomas (46) |
| Presence of ESX-1 secretion system? | Yes (7, 8, 31, 33) | Yes (6, 9) |
| Susceptibility to first-line antibiotics, by MIC (μg/ml) | Isoniazid, 0.1 | Isoniazid, 16 |
| Rifampicin, 0.5 | Rifampicin, 1.0 | |
| Ethambutol, 4 (195) | Ethambutol, 1.0 (197, 198) | |
| Pyrazinamide, 25 (196) | Pyrazinamide, intrinsically resistant (4) | |
a
LOS, lipooligosaccharide; TNF-α, tumor necrosis factor alpha; KO, knockout; IL-10, interleukin-10; TDM, trehalose-6-6-dimycolate; PGL, phenolic glycolipids.