Molecular genetic characterization of human Cryptosporidium isolates and their respective demographic, environmental and clinical manifestations in Egyptian diarrheic patients

Abstract

Background: Cryptosporidium is a zoonotic protozoan parasite of public health and veterinary importance, causing gastroenteritis in a variety of vertebrate hosts. Several Cryptosporidium spp. with different genotypes and subtypes are implicated in human cryptosporidiosis. Objective: Detection and correlation of native Cryptosporidium molecular genetic variability among Egyptian diarrheic human isolates with their respective demographics, environmental and clinical manifestations. Patients and Methods: A total of 350 human stool samples were collected from diarrheic patients. The collected samples were examined microscopically and by RIDA®QUICK Cryptosporidium/Giardia copro-immunochromatography test (ICT) cassettes and strips. All positive Cryptosporidium samples detected by modified Ziehl-Neelsen stain (MZN) and/or ICT were genotyped using nested polymerase chain reaction-restriction fragment length polymorphism (nPCR-RFLP) targeting cowp gene encoding Cryptosporidium oocyst wall protein ( Cowp). Results: Cryptosporidium was detected in 5.7% (20/350) of the examined samples using MZN, 9.4% (33/350) by ICT kit, and 3.7% (13/350) by both methods. A total of 40 samples were positive by both microscopy and/or ICT. Only 15/40 (37.5%) of samples positive by microscopy and/or ICT were successfully amplified using cowp gene. All amplified samples (15) were confirmed as C. hominis by nPCR-RFLP analysis of the cowp gene. Significant associations were found between cryptosporidiosis and gender, drinking groundwater, immunodeficiency of patients, complaining of fever, watery and mucoid stool, consumption of readymade salad, and unwashed fresh vegetables. Conclusion: In the current examined samples, C. hominis proved to be the dominant genotype, indicating that transmission of cryptosporidiosis among a sample of diarrheic Egyptian patients is most probably anthroponotic rather than zoonotic. MZN and PCR gave a diagnostic accuracy of 100%, while ICT diagnostic accuracy proved to be 50%.