Gram stain: Difference between revisions

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= Gram stain =
 
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== Procedure ==
 
== Procedure ==
   
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* Fix to slide with heat
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* Fix to slide with heat or methanol
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* Crystal violet, and wait 60 seconds
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* Add crystal violet, and wait 60 seconds
 
* Wash with water then flood with iodine, and wait 60 seconds
 
* Wash with water then flood with iodine, and wait 60 seconds
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* Wash with water then decolorize with 95% alcohol
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* Wash with water then decolorize with 95% ethanol or acetone
 
* Counter-stain with safrinin, wait 30 seconds then wash off with water
 
* Counter-stain with safrinin, wait 30 seconds then wash off with water
   
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* Gram-negative = red
 
* Gram-negative = red
 
* Peptidoglycan layer (cell wall) is thick with extensive cross-linking in gram-positive
 
* Peptidoglycan layer (cell wall) is thick with extensive cross-linking in gram-positive
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[[Category:Diagnostics]]

Latest revision as of 20:50, 29 April 2020

Procedure

  • Fix to slide with heat or methanol
  • Add crystal violet, and wait 60 seconds
  • Wash with water then flood with iodine, and wait 60 seconds
  • Wash with water then decolorize with 95% ethanol or acetone
  • Counter-stain with safrinin, wait 30 seconds then wash off with water

Interpretation

  • Gram-positive = blue
  • Gram-negative = red
  • Peptidoglycan layer (cell wall) is thick with extensive cross-linking in gram-positive