| Genus | Species Num | Strain Num | SOURCE |
|---|---|---|---|
| Marvinbryantia | 1 | 2 | HMP/MGYG |
| Massilibacterium | 1 | 1 | MGYG |
| Massilimicrobiota | 1 | 1 | MGYG |
| Massilioclostridium | 1 | 1 | MGYG |
| Mediterraneibacter | 3 | 3 | HMP |
| Megamonas | 2 | 2 | MGYG |
| Megasphaera | 3 | 3 | HMP/MGYG |
| Meiothermus | 2 | 2 | HMP |
| Mesomycoplasma | 3 | 3 | HMP |
| Mesoplasma | 1 | 1 | HMP |