Enteric pathogenic protozoa from misdiagnosis to overmedication in Egypt: a need for molecular diagnosis

Cryptosporidium spp., Entamoeba histolytica ( E. histolytica ), and Giardia intestinalis ( G. intestinalis ) are prevalent in developed and developing countries, including Egypt. These enteric protozoa usually provoke indistinguishable manifestation including diarrhea. There is scarce studies of their true prevalence in Egypt. We aimed to identify the accurate detection of these enteric pathogenic protozoa from human diarrheic samples using a multiplex-PCR (MT-PCR) assay and to evaluate the diagnostic performance of coproscopy and monoplex nested PCR (nPCR). Fecal specimens were collected from 100 diarrheic patients and were examined coproscopically and molecularly using MT-PCR and nPCR assays. Diagnostic yield using MT-PCR, nPCR, and microscopy revealed 25, 24, and 15 cases, respectively, for G. intestinalis and 12, 9, and 2 cases, respectively, for Cryptosporidium spp. Coproscopy showed six positive samples for E. histolytica complex , while E. histolytica copro-DNA was not recovered in any sample. Coproscopy showed lower sensitivity than copro-MT-PCR in identifying Cryptosporidium spp. (17%) and G. intestinalis (60%) with 100% specificity. Coproscopy has limited specificity for detection of E. histolytica complex . Compared to MT-PCR, nPCR showed a sensitivity of (75%) for Cryptosporidium spp. and (96%) for G. intestinalis , with 100% specificity for both parasites. G. intestinalis and Cryptosporidium spp. were the prevailing diarrhea-causing protozoa, while E. histolytica was absent among examined Egyptians. Copro-PCR assays could distinguish between pathogenic E. histolytica and non-pathogenic Entamoeba dispar avoiding misdiagnosis and overmedication. Subsequently, MT-PCR allows simultaneous detection of the three protozoa in a single, affordable, and less time-consuming reaction with high sensitivity and specificity.