Molecular characterization of Cystoisospora belli and unizoite tissue cyst in patients with Acquired Immunodeficiency Syndrome

Abstract

Cystoisospora belli is a coccidian protozoan that can cause chronic diarrhoea, acalculous cholecystitis and cholangiopathy in AIDS patients. We applied molecular methods to identify Cystoisospora at species level in AIDS patients presenting with and without the presence of unizoites in lamina propria. Coprological and histological analyses were performed in stool and/or biopsy samples from 8 Cystoisospora-infected patients. DNA from the same samples was used to amplify 2 fragments of the SSU-rRNA gene and the ITS-1 region. Sequencing of the resulting amplicons identified C. belli infections in all cases, independent of the presence or absence of unizoite tissue cysts. Further work should be considered in order to find molecular targets related to strain variations in C. belli.

Enteric Protozoa in the Developed World: a Public Health Perspective

“…Cystoisospora belli is often implicated in traveler's diarrhea in travelers to developing countries with high levels of endemicity (2,156,311,313,427). It is more common in AIDS patients (165,230,453), other immunocompromised patients (163,227,266,336,344), and indigenous populations in the United States (291,315). In HIV-infected patients, infection may be characterized by chronic diarrhea, acalculous cholecystitis cholangiopathy, and extraintestinal infection (337,453).…”

“…It is more common in AIDS patients (165,230,453), other immunocompromised patients (163,227,266,336,344), and indigenous populations in the United States (291,315). In HIV-infected patients, infection may be characterized by chronic diarrhea, acalculous cholecystitis cholangiopathy, and extraintestinal infection (337,453). Other Cystoisospora species are important causes of diarrhea in domestic animals (108), and Cystoisospora suis is an economically important parasite causing severe diarrheal illness in pigs (8,212,282).…”

“…Diagnosis has also been done from mucosal biopsy specimens (227,453). Molecular techniques such as conventional and realtime PCR can be used to augment diagnosis where possible, since these methods can be more sensitive in detecting infection (283).…”

“…Molecular techniques such as conventional and realtime PCR can be used to augment diagnosis where possible, since these methods can be more sensitive in detecting infection (283). However, while PCRs have shown excellent sensitivity and specificity for the detection of C. belli in fecal samples, these are neither widely nor commercially available (283,337,347,390,427,453). Infection usually responds to treatment with oral cotrimoxazole, and where resistance or intolerance exists, ciprofloxacin is a good alternative (109).…”

Molecular Testing for Clinical Diagnosis and Epidemiological Investigations of Intestinal Parasitic Infections

“…Sporozoites released into the small bowel by ingested oocysts invade the intestinal epithelium, and once intracellular, the parasites undergo schizogony with merozoite, trophozoite, schizont, gametocyte, and oocyst formation (196,197). Tissue cysts (lamina propria) may be seen by endoscopy in the absence of fecal shedding of oocysts; tissue cysts may be unizoite (208,209). Oocysts are oblong and characterized by a thin, transparent shell surrounding the sporocysts and are usually detected in the laboratory by Ziehl-Neelsen staining of fecal concentrates (Fig.…”