| Genus | Species Num | Strain Num | SOURCE |
|---|---|---|---|
| Acidiphilium | 1 | 1 | HMP |
| Acidithiobacillus | 2 | 2 | HMP |
| Acidobacterium | 1 | 1 | HMP |
| Acidothermus | 1 | 1 | HMP |
| Acidovorax | 4 | 4 | HMP/MGYG |
| Acinetobacter | 15 | 31 | HMP/MGYG |
| Actinobacillus | 3 | 4 | HMP |
| Actinobaculum | 1 | 1 | MGYG |
| Actinomyces | 3 | 5 | HMP/MGYG |
| Actinosynnema | 1 | 1 | HMP |