Table 3. Features of the infectious agent.
| Identification | Strain n | Beijing Lineage | Location of diagnosis | Period | Mϕ virulence level | n secondary cases | Ab resistant |
| Madrid 1 | 1 | YES | Madrid | High | - | NO | |
| Madrid 2 | 2 | YES | Madrid | High | - | INH-R | |
| Madrid 3 | 3 | NO | Madrid | 1997–2004 | Low | 45 | NO |
| Madrid 4 | 4 | YES | Madrid* | Low | - | NO | |
| GC 1237 | 5 | YES | Gran Canaria | 1993–1996 | ND | 75 | NO |
| HMS 1292 | 6 | NO | Zaragoza | ND | - | NO | |
| MTZ | 7 | NO | Zaragoza | 2001–2004 | ND | 85 | NO |
Abbreviations: n: number; ND: Not Done; Mϕ: Macrophage; Ab: Antibiotic.
(*): Isolates 4 and 5 are representative of the same strain and corresponded to initial (Isolate 5, Gran Canaria) or final (Isolate 4, Madrid) stages of its dissemination.