Comparison of staining techniques and multiplex nested PCR for diagnosis of intestinal microsporidiosis.

Microsporidiosis is increasingly being recognized as the cause for diarrhea in immunocompromised patients. The 2 most common microsporidia causing gastrointestinal infection worldwide are Enterocytozoon bieneusi and Encephalitozoon intestinalis. The aim of present study was to evaluate different techniques for detection of intestinal microsporidia in human stool samples. The fecal samples of 395 individuals including 125 HIV-seropositive patients with diarrhoea, 158 HIV-seropositive patients without diarrhoea, 55 HIV-seronegative patients with diarrhoea, and 57 healthy controls were used for detection of microsporidia by modified trichrome staining, calcofluor staining, and multiplex polymerase chain reaction (PCR). PCR had the highest sensitivity of 100%, while its specificity was 97.9%. Trichrome staining had highest specificity of 100% but a sensitivity of 63.8% only, and calcofluor white had a sensitivity and specificity of 79.7% and 82.2%, respectively. Thus, for diagnosis of intestinal microsporidiosis, it is important to perform PCR as staining techniques are not good enough to detect microsporidia in stool samples and for their species identification.