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UND 363 Fite
| Question | Answer |
|---|---|
| principle for Fite A/F Stain | demo of mycobacteria leprae (leprosy causing bacteria) |
| Principle for Fite A/F Stain | lipoid capsule of A/F mycobacteria takes up carbol fuchsin and resists decolorization with dilute mineral ACID. |
| fix for Fite A/F Stain | NBF preferred, others can be use but NOT CARNOYS |
| microns | 4-5 |
| qc | tissue with leprosy organism, must use Millipore filtered (.45 micron pore size) water, and a negative control from same day workload. |
| reagents in order for Fite A/F Stain | xylene/peanut oil (deparaffinize & prevent shrinkage/tissue injury), Ziehl-neelsen Carbol Fuchsin soln', adic/alcohol - decolorize, methylene blue(w/acetic acid) - counterstain, air dry and mount with synthetic resin (avoid alcohol and xylene) |
| results | Myco. leprae and other A/F - bright red, background - lt blue |
| How is this stain compared to kinyoun and Ziehl-neelsen for mycobacteria | not AS GOOD except for mycobacteria leprae |
| what enhances the acid fastness of leprocy myco. | peanut oil and xylene mixture protect the waxy capsule....AND the avoidance of dehydrating solutions |
| why should acohol be avoided for Myco leprae and Nocardia | they are WEAKLY A/F and not alcohol fast therefore alcohol should be avoided. |
| if the Fite stain is used for Nocardia what changes must be made | stain in carbol fuchsin for 10 min (time is critical), decolorize with 1% aqueous sulfuric acid, wash in water, counterstain with methylene blue, dry and mount slides (AVOID alcohol and xylene) |
| what are the results of the Fite stain when used for NOCARDIA | nocardia - red, background - blue |