DETECTION OF BLASTOCYSTIS SPP. IN STOOLS OF DIARRHEIC CHILDREN USING IN VITRO CULTIVATION AND MICROSCOPY
Fayza Sayed Habib
Department of Parasitology, Faculty of Medicine, Ain Shams University Cairo, Egypt.
The objective of the present study was to detect the occurrence of Blastocystis spp. among diarrheal children with or without immunosuppressant conditions and to compare different microscopic, concentration and staining techniques as well as to determine the usefulness of in vitro cultivation of stool samples in detection of Blastocystis spp. From June 2008 to December 2009, stool samples from 600 pediatric diarrheic patients attending the outpatient clinics of Ain Shams and Cairo University pediatric hospitals were examined for identification of the parasite using culture in Jones medium, direct wet monts, different concentration methods (Formalin ethyl-acetate sedimentation, and Sheather`s sucrose floatation) and different stains (Trichrome, modified Ziehl Neelsen, Giemsa and acridine orange stains). Patients were included in two groups: immunocompetent (Group I) and immunocompromized (Group II) patients. Blastocystis spp. was detected in 19.6% of 300 diarrheal children without immunosuppressant conditions and 34.6% of 300 diarrheal children with immunosuppressant conditions with significant difference between the two groups. In vitro cultivation was of 100% sensitivity. FEA sedimentation was significantly more sensitive than direct smear and Sheather’s floatation (with sensitivities of 87.1%, 73.6% and 25.1%, respectively). Additionally, the modified trichrome was the best staining method. Blastocystosis predominated in the age group 1-4 years compared to other age groups. Blastocystis was found as a sole parasite in 83 out of 163 (50.9%) infected children. Co-infection with other pathogenic parasites occurred in 80 cases; most commonly Cryptosporidium (31/163). It was concluded that blastocystosis is common among diarrheal children especially if it is associated with immunosuppressant conditions. Feces examination for Blastocystis using in vitro culture and the trichrome staining are recommended for diagnosis.