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Background: Blastocystis hominis (B. hominis) is a cosmopolitan intestinal protozoan that has been related to several gastrointestinal disturbances simulating irritable bowel syndrome (IBS). However, the underlying pathogenicity of blastocystosis in human studies remains indistinct. Methods: In a cross-sectional study, 167 stool samples from patients attending internal medicine department, Kafrelsheik university hospital were examined. Polymerase chain reaction (PCR) -based identification using known sequenced-tagged site (STS) primers allowed the isolation of the positive samples and genotyping of the parasite. Reducing sugar and pH were investigated in patients’ stool samples. Results: Patients who participated in the study were from both sexes where blastocystosis infection was most prevalent in the age group 20 – 29. Of 167 cases, twenty-seven (16.1%) were molecularly confirmed blastocystosis infections. Genotype 3 was solely detected. Of these, 26 (19%) cases presented with diarrhea, and 27 (17.1%) cases suffered abdominal pain. Additionally, 20 (16.8%) cases had increased flatulence, and only two patients manifested vomiting. The seasonal cycle of the parasite was explored being higher in summer and spring. Our results highlight the consistent chemical association of carbohydrate intolerance and acidic fecal pH with genotype-3 of B. hominis that seemed to augment the irritable bowel syndrome (IBS) -like manifestations of the parasitic infection. Specimens positive for B. hominis showed dominant growth of E. coli. Co-culture of B. hominis with E. coli and Candidashowed their eminent growth whereas the parasite was suppressed. B. hominiswith Giardia species co-infections showed a significant rise in lactate dehydrogenase (LDH) enzyme in fecal samples compared with B. hominissolely. Conclusion: there is an association between Blastocystis hominis infections and carbohydrate intolerance and fecal acidity. B. hominis was observed to be closely related to IBS-like manifestations with the dominatingly isolated genotype-3. Also, B. hominis appeared to have an enhancing effect on the growth of E. coli and C. non-albicans. Blastocystosis seemed to heve damaging effects on the cells of the intestinal brush border especially when co-existing with Giardia sp. thus increasing levels of LDH. |
