| Species | RefIntense Num | Refseq Num | Source |
|---|---|---|---|
| Oenococcus oeni | 1 | 231 | HMP |
| Olegusella massiliensis | 1 | 2 | MGYG |
| Oleidesulfovibrio alaskensis | 1 | 2 | HMP |
| Olsenella uli | 1 | 6 | HMP |
| Opitutus terrae | 1 | 1 | HMP |
| Oribacterium sinus | 3 | 2 | HMP/MGYG |
| Oribacterium sp. oral taxon 078 | 1 | 2 | HMP |
| Orientia tsutsugamushi | 2 | 17 | HMP |
| Oscillibacter ruminantium | 1 | 1 | MGYG |
| Oxalobacter formigenes | 4 | 7 | HMP/MGYG |