Detection of Blastocystis species in immunocompromised patients (cancer, diabetes mellitus, and chronic renal diseases) by restriction fragment length polymorphism (RFLP)

Background

Blastocystis spp. is an anaerobic protozoan intestinal parasite, it comprises multiple subtypes (STs), with ST1 to ST9 being isolated from humans worldwide. Using polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP), these subtypes are classified into four groups (A to D). This study aimed to detect Blastocystis spp. groups in immunocompromised patients and evaluate their correlation with clinical presentations.

Materials and methods

A cross-sectional study was conducted on 150 immunocompromised patients and 50 immunocompetent individuals. All subjects were evaluated for socio-demographic data, clinical features, and parasitic infections. RFLP analysis of the SSU rRNA gene was performed for Blastocystis spp. grouping.

Results

Among 150 immunocompromised patients, Blastocystis spp. was detected in 83.3% by direct wet mount and 94.7% by PCR, showing significant difference (P = 0.003) compared to immunocompetent individuals (40% and 50%, respectively). Of the PCR-positive immunocompromised patients, 86.7% were symptomatic, with diarrhea being the most common symptom (66%). In immunocompromised patients, group B of Blastocystis spp. subtypes (ST3, ST4, and ST8) dominated (86.7%). On the other hand, just 12% of immunocompetent people had symptoms, with group A subtypes (ST1 and ST2) accounting for 38% of the study cases.

Conclusion

Blastocystis spp. group B (ST3, ST4, and ST8) showed higher prevalence than group A (ST1 and ST2) in immunocompromised patients, with diarrhea being the most common clinical manifestation.