are shown here in an acid fast stain at 1000 X. These pathogenic
bacteria are present in a sputum specimen from a patient with tuberculosis.
Other non-acid fast bacteria are also visible. Mycobacterium
are said to be "acid-fast" because they retain the red primary dye (carbolfuchsin)
even when exposed to acid-alcohol. Most other bacteria lose the carbolfuchsin
dye and then absorb the methylene blue counterstain, resulting in blue
non-acid-fast organisms and red acid-fast
stain organisms.
 |
 |
 |
 |
 |
|---|---|---|---|---|
| 1. | 2. | 3. | 4. | 5. |
 |
 |
 |
 |
 |
| 6. | 7. | 8. | 9. | 10. |
© 1998