A new and improved "quick-hot Gram-chromotrope" technique that differentially stains microsporidian spores in clinical samples, including paraffin-embedded tissue sections

Arch Pathol Lab Med. 1997 Aug;121(8):888-93.


Objective: This report describes a new and improved "quick-hot Gram-chromotrope" staining technique that detects microsporidian spores in clinical specimens, such as stool, urine, saliva, nasopharyngeal fluid, and bronchoalveolar lavage samples, as well as in formalin-fixed and paraffin-embedded tissue sections.

Design: In this procedure, the samples are stained in heated (50 degrees C to 55 degrees C) solutions of crystal violet and iodine used in Gram's stain, followed by a modified chromotrope solution (heated to 50 degrees C to 55 degrees C). The modified stain is composed of chromotrope 2R (1%), fast green (0.15%), and phosphotungstic acid (0.25%).

Results: With this stain and the new protocol, microsporidian spores are stained dark violet against a pale green background, and the total staining time is shortened to 5 minutes.

Conclusions: This new technique is fast, reliable, and simple. It can be easily adapted for use in clinical laboratories.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Fluids / parasitology
  • Cell Culture Techniques
  • Feces / parasitology
  • Gentian Violet / chemistry*
  • Humans
  • Intestinal Diseases, Parasitic / diagnosis*
  • Microsporida / chemistry
  • Microsporida / isolation & purification*
  • Microsporida / physiology
  • Microsporidiosis / diagnosis*
  • Paraffin Embedding
  • Phenazines / chemistry*
  • Spores / chemistry
  • Staining and Labeling / methods*


  • Gram's stain
  • Phenazines
  • Gentian Violet