DIAGNOSIS OF INTESTINAL MICROSPORIDIOSIS BY EXAMINATION OF STOOL AND DUODENAL ASPIRATE WITH WEBERS MODIFIED TRICHROME AND UVITEX 2B STAINS

Severe, chronic diarrhea is a frequent complication of human immunodef iciency virus disease, and intestinal microsporidiosis is being recogn ized with increasing frequency in patients with AIDS. Noninvasive, cos t-effective techniques are needed to optimize its diagnosis. Weber's m odified trichrome stain (MTS) and the fluorochrome Uvitex 2B stain wer e used to detect microsporidial spores in smears of stool and duodenal aspirate (DA) samples received from human immunodeficiency virus-infe cted patients for examination for ova and parasites. Of 305 samples (2 92 stool and 13 DA samples) from 140 patients examined by MTS, 83 samp les from 26 (18.6%) of the patients were positive for microsporidia (2 3 patients diagnosed initially and 3 diagnosed upon review). A subset of the samples studied by MTS consisting of 108 smears of stool and DA specimens from 60 patients was examined by Uvitex 2B. All 44 samples positive by MTS were also positive by Uvitex 2B. In addition, seven sp ecimens acid three patients were initially detected as positive by Uvi tex 2B only (all three patients were positive also by MTS upon review) . Confirmation of the diagnosis was obtained for 24 of 26 smear positi ve patients by duodenal biopsy and/or stool transmission electron micr oscopy. Of 114 patients with stained smears negative for microsporidia , 23 had duodenal biopsies which showed no microsporidia. For the 43 p atients who underwent duodenal biopsy, the sensitivity of both the MTS and the Uvitex 2B methods compared with biopsy results was 100%. Of s ix patients with negative duodenal biopsies and positive stained smear s, four had microsporidia demonstrated by stool transmission electron microscopy, The examination of stool and DA smears stained by Uvitex 2 B and/or MTS is a sensitive, noninvasive test for diagnosis of intesti nal microsporidiosis which can be successfully implemented in a clinic al laboratory. Strict adherence to precise diagnostic criteria is nece ssary to avoid incorrect results., The simultaneous use of both staini ng methods enhances performance and may provide greater accuracy, espe cially for patients with light infections.