Molecular characterization of clinical isolates of Cyclospora cayetanensis from patients with diarrhea in India.
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Date
2015-07
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Abstract
Purpose: Cyclospora cayetanensis is an intestinal coccidian protozoan that has emerged as an important cause of
both epidemic and endemic protracted diarrhea worldwide. Though humans appear to be the only natural hosts;
the role of animals as natural reservoir is uncertain but of increasing concern. The present study aimed to study the
prevalence of coccidian in different groups such as immunocompromised, clinically apparent immunocompetent
and healthy individuals. Also, the study isolates were assessed for heterogeneity among the sequences.
Materials and Methods: Stool samples from different groups of patients were collected. The parasite was detected in
stool by different diagnostic tools such as light microscopy and nested PCR‑restriction fragment length polymorphism
using 18S ribosomal RNA as the target gene. Results: The prevalence of C. cayetanensis was 2.4% (19/800) in the
present study. The PCR assay amplified Cyclospora cayetanensis DNA in only 89% (17/19) isolates. Further, sequencing
revealed no significant difference among the study isolates and the non‑primates. Phylogenetic analysis of the study
isolates however, formed two clusters. While one cluster showed close evolutionary association with the C. cayetanensis
strains, the other cluster showed evolutionary association with the two non‑primate species. Conclusion: The methods
described here for detection of C. cayetanensis oocysts are simple, efficient, specific, and sensitive and therefore can be
effectively applied for laboratory diagnosis and environmental assessment of fresh produce and water sources. Clinicians
should include Cyclospora infection in the differential diagnosis of prolonged or relapsing diarrheal illness even in
clinically apparent immunocompetent individuals.
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Keywords
Diarrhea, prevalence, phylogenetic analysis
Citation
Yadav P, Khalil S, Mirdha BR, Makharia GK, Bhatnagar S. Molecular characterization of clinical isolates of Cyclospora cayetanensis from patients with diarrhea in India. Indian Journal of Medical Microbiology. 2015 Jul-Sept; 33 (3): 351-356.