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Clinical and microscopical features of small-intestinal microsporidiosis in patients with AIDS
P Caramello1, G Mazzucco, M Romeo
1Institute of Infectious Diseases, University of Turin, Italy.
Abstract:
Intestinal microsporidiosis by Enterocytozoon bieneusi is an increasingly recognized infection in AIDS patients. We report eight cases of microsporidiosis. All patients were severely immunodepressed. Clinical features were highly variable. Patients were followed up for a mean period of 7.8 months. All patients had persistent infection during the follow-up and spore excretion remained constant. Two patients became asymptomatic during the follow-up. None of the patients presented clinical and echographic signs of biliary involvement. Treatment with albendazole, metronidazole or paromomycin failed to produce a durable clinical response or to eradicate the organism. Cases were identified by stool examination and additionally investigated with light and electron microscopy. It was found that light microscopy was a sensitive method, while electron microscopy was less sensitive but allowed the definition of the infecting species. The modified trichrome stain was a satisfactory method for diagnosis on fecal smears. The calcofluor stain and the combination of DAPI with calcofluor was a rapid and simple staining method for screening.
Insights
Enterocytozoon bieneusi infections in AIDS patients are persistent and difficult to treat. Diagnosis can be achieved through stool examination using modified trichrome or calcofluor stains.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Immunology
Background:
- Intestinal microsporidiosis caused by Enterocytozoon bieneusi is a growing concern in individuals with Acquired Immunodeficiency Syndrome (AIDS).
- This study focuses on eight severely immunocompromised AIDS patients diagnosed with this infection.
Observation:
- Clinical presentations of microsporidiosis were diverse among the patients.
- Patients were monitored for a mean of 7.8 months, with persistent infection and constant spore excretion observed.
- Two patients experienced spontaneous asymptomatic states during the follow-up period.
- No patients exhibited clinical or echographic evidence of biliary tract involvement.
Findings:
- Antimicrobial treatments including albendazole, metronidazole, and paromomycin did not achieve durable clinical responses or organism eradication.
- Light microscopy proved to be a sensitive diagnostic method for Enterocytozoon bieneusi in stool samples.
- Electron microscopy, while less sensitive, was crucial for species identification.
- Modified trichrome stain demonstrated satisfactory diagnostic performance on fecal smears.
- Calcofluor stain and DAPI-calcofluor combination offered rapid and simple screening methods.
Implications:
- The findings underscore the challenges in treating Enterocytozoon bieneusi infections in AIDS patients, suggesting current therapies are often inadequate.
- The study highlights the utility of various microscopy techniques, particularly light microscopy with modified trichrome stain, for reliable diagnosis.
- Development of more effective therapeutic agents and diagnostic tools for intestinal microsporidiosis is warranted.