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Improved light-microscopical detection of microsporidia spores in stool and duodenal aspirates. The Enteric
1Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control, Atlanta, GA 30333.
Background:
The diagnosis of infection with Enterocytozoon bieneusi, a microsporidian organism that causes chronic diarrhea in patients infected with the human immunodeficiency virus (HIV), has depended on invasive procedures. We have developed a new method to detect microsporidia spores in feces and duodenal aspirates.
Methods:
Stool was obtained from four HIV-infected patients with biopsy-confirmed intestinal microsporidiosis. Slides prepared from unconcentrated, formalin-fixed stool specimens were stained with a new chromotrope-based technique and examined by light microscopy. Methods of stool concentration were also compared. The technique was then evaluated by examining 215 specimens from 134 HIV-infected persons with or without diarrhea. In addition, duodenal aspirates from 10 patients with unexplained chronic diarrhea were examined by light microscopy after staining according to the new and the traditional techniques.
Results:
E. bieneusi spores were found in all unconcentrated stool specimens from the four patients with microsporidiosis. The use of various methods of stool concentration did not improve the detection of microsporidia spores. In the prospective study, microsporidiosis was detected in samples from 6 of 27 patients with chronic diarrhea, but in none of those from 42 patients with acute diarrhea or 65 patients without diarrhea. The presence of microsporidia spores in stool specimens and duodenal aspirates allowed the successful prediction of the presence of microsporidia in small-bowel biopsy specimens from all four patients who subsequently underwent endoscopy.
Conclusions:
E. bieneusi is an important cause of chronic diarrhea in HIV-infected persons. This new diagnostic technique serves as a practical, noninvasive means to detect microsporidia spores in stool specimens and is also applicable to the examination of duodenal aspirates.
Insights
A new noninvasive diagnostic method accurately detects Enterocytozoon bieneusi spores in stool and duodenal samples. This technique aids in diagnosing microsporidiosis, a cause of chronic diarrhea in HIV-infected individuals.
Area of Science:
- Medical Parasitology
- Infectious Diseases
- Gastroenterology
Background:
- Enterocytozoon bieneusi causes chronic diarrhea in HIV-infected patients.
- Current diagnosis relies on invasive procedures.
- A novel, noninvasive diagnostic method has been developed.
Purpose of the Study:
- To develop and evaluate a new diagnostic technique for Enterocytozoon bieneusi.
- To assess the utility of this method in detecting microsporidia spores in stool and duodenal aspirates.
- To provide a practical, noninvasive diagnostic alternative.
Main Methods:
- A new chromotrope-based staining technique was used for light microscopy.
- Unconcentrated stool specimens from HIV-infected patients were examined.
- The technique was validated on 215 specimens from 134 HIV-infected individuals and 10 duodenal aspirates.
Main Results:
- The new technique detected E. bieneusi spores in all tested stool samples from patients with microsporidiosis.
- Stool concentration methods did not enhance spore detection.
- Microsporidiosis was identified in 6 of 27 HIV-infected patients with chronic diarrhea.
Conclusions:
- Enterocytozoon bieneusi is a significant cause of chronic diarrhea in HIV-infected individuals.
- The developed diagnostic technique is practical and noninvasive.
- This method is effective for detecting microsporidia spores in stool and duodenal aspirates.