Molecular detection of Cystoisospora belli by single-run polymerase chain reaction in stool samples

INTRODUCTION

Cystoisospora belli (C. belli) is the only pathogenic species of the Cystoisospora genus responsible for severe diarrhea in immunocompromised patients. Most common microscopic method of diagnosis is less sensitive due to intermittent shedding of oocysts. We developed a new single-run polymerase chain reaction (PCR)-based diagnostic assay for C. belli.

METHODS

A new single-run PCR-based diagnostic assay was standardized for the detection of C. belli. Diagnostic reproducibility and repeatability of the PCR assay were evaluated. A cross-sectional analytical study was done on a total of 354 stool samples collected from 331 immunocompromised patients with diarrhea. All the stool samples were tested for the presence of oocysts of C. belli and were also tested by our new PCR assay for C. belli. Three of the representative PCR products were confirmed by sequencing. Fisher's exact test was used to compare the two proportions.

RESULTS

Microscopy detected C. belli in 11/354 (3.1%) of stool samples, and the new PCR-based assay detected C. belli in 16/354 (4.5%). The new single-run PCR-based assay detected C. belli in all the stool samples which were tested positive by microscopy and additionally detected C. belli in five stool samples. The developed PCR assay detected statistically significant proportion of C. belli (p < 0.001) as compared to microscopy. The 795 base pair PCR product from one microscopy positive stool sample and two microscopy negative stool samples were confirmed by sequencing.

CONCLUSION

Our newly developed single-run PCR-based detection assay for C. belli is robust and reproducible. It may be used for molecular diagnosis of cystoisosporiasis especially in transplant, pediatrics, and human immunodeficiency virus (HIV) positive patients.

Prevalence of Opportunistic Intestinal Parasitic Infections Among HIV/AIDS Patients Before and After Commencement of Antiretroviral Treatment at Felege Hiwot Referral Hospital: A Follow-up Study

Background

Coccidian parasites are opportunistic intestinal parasites that cause diarrhea in immunocompromised individuals. Although the impacts of coccidian infection are significant among HIV/AIDS infected cases, proper diagnosis and management of coccidian infection is limited in sub-Saharan Africa including Ethiopia.

Objective

The aim of this study was to determine the prevalence of coccidian parasitic infections among HIV/AIDS cases before and after commencement of antiretroviral treatment.

Methods

An institution-based longitudinal study was conducted among 304 randomly selected HIV/AIDS cases from February to July 2018 before and after commencement of antiretroviral therapy. A structured questionnaire was used to collect sociodemographic and associated factors data. Stool and blood samples were collected before and three months after treatment. Coccidian detection and CD4⁺ count were conducted via modified acid fast stain technique and fluorescence-activated cell scanning, respectively. Data were entered and analyzed using SPSS version 20. Descriptive statistics were used to compute coccidian prevalence. Logistic regression was used to compute possible association between associated factors and coccidian parasitic infection. Variables with P<0.05 were considered to be statistically significant.

Results

Among 304 HIV/AIDS cases, prevalence of coccidian parasitic infection before and after antiretroviral treatment was 23.4% and 8.9%, respectively. Prevalence of Cryptosporidium spp. (19.7%) and Isospora belli (4.3%) before antiretroviral treatment were higher than Cryptosporidium spp. (7.9%) and Isospora belli (1.0%) after treatment. Drinking unprotected water (AOR: 7.41; 95%CI: 1.64–33.45), poor knowledge of HIV/AIDS and coccidian parasite (AOR: 4.19; 95%CI: 1.69–10.40), and CD4⁺ count below 200 cells/mm³ (AOR: 62.49; 95%CI: 25.32–154.21) were significantly associated with coccidian infection.

Conclusion

Prevalence of coccidian parasites among HIV/AIDS cases decreases after antiretroviral treatment. Drinking unsafe water, limited knowledge of HIV/AIDS and coccidian parasite and low CD4⁺ cell count are factors associated with coccidian infection. Therefore, proper detection and treatment of coccidian parasites among HIV/AIDS cases should be prioritized.

[Dynamic Abundance of Oocysts in the Mezam Watershed in Bamenda (Northwest Region, Cameroon)]

In order to evaluate the abundance of oocysts in the Mezam watershed in Bamenda, Northwest Region of Cameroon, a study was carried out from January to June 2017. Samples were collected monthly from 13 stations within the watershed. The direct concentration method and the Ziehl-Neelsen technique were employed in the identification of these parasites. The physicochemical analysis showed that the water samples had a neutral pH (7.46±0.46), lowly mineralized (165.61±110.02μS/cm), moderately oxygenated (60.64 ± 17, 25%), present moderate organic pollution (2.85±2.49mg/l KMnO4). KMnO₄) and low levels of orthophosphate (1.8±1.88 mg/l PO₄^3-) and nitrates (2.47±5.06 mg/l NO₃^-). Biological analysis revealed the presence of Cryptosporidium spp. (143.98±203.35 oocysts/l), Isospora belli (88.47 ± 123.19 oocysts/l), Cyclospora cayetanensis (141.31±143.19 oocysts/l) and Sarcocystis hominis (76 ± 111.04 oocysts/l). The highest densities of these parasites were recorded at the Mufueh stream, situated in the periurban area. Meanwhile, the lowest densities were found in the urban area (Formuki, Mankon, Ayaba and Mezam streams). The dry season showed higher densities of oocysts (471.42±216.32 oocysts /l). Statistical analysis revealed a significant correlation (P ≤ 0.05) between the density of the organisms and the physico-chemical parameters such as pH, oxidability, dissolved oxygen and nitrates. Respecting basic hygienic rules as well as treating water before use would reduce the risk of contamination of the population.

[Abundance Dynamic of Oocysts in the Groundwater of Mbankomo, a Sub-urban Area Yaounde: Physico-chemical Factors and Health Risk]

To determine the dynamics of dissemination of the different forms of enteric sporozoa in the groundwater of Mbankomo, a study was carried out from August 2018 to July 2019. The physico-chemical analyzes were carried out both in the field and in the hydrobiology and environment laboratory of the University of Yaoundé I. The observation of protozoan oocysts was carried out after application of the Ziehl-Neelsen staining. Physico-chemical analysis showed slightly acidic water (6.32 ± 0.43 UC), with high turbidity (31.30 ± 23.56 mg/l). Biological analysis indicated the presence of protozoan oocysts with an average density of 42 ± 69 oocysts/l of Cryptosporidium spp., 17 ± 34 oocysts/l of Cyclospora cayetanensis, 9 ± 19 oocysts/l of Isospora belli and 6 ± 11 oocysts/l of Sarcocystis spp. The highest concentrations of oocysts were recorded during the rainy season. Statistical tests showed a positive correlation between the densities of oocysts with suspended matters (P < 0.05).

Isospora belli) in continuous cell lines

Cystoisospora belli is an opportunistic protozoan that causes human cystoisosporiasis, an infection characterized by diarrhea, steatorrhea, abdominal pain, fever, and weight loss. The lack of animal models susceptible to C. belli, and the difficulty in obtaining clinical samples with fair amounts of oocysts have limited the research pertaining to the basic biology of this parasite. This study aimed to describe the ultrastructure of endogenous stages of C. belli in Monkey Rhesus Kidney Cells (MK2) and Human Ileocecal Adenocarcinoma cells (HCT-8). Zoites of C. belli exhibited typical morphological features of coccidia, which included a trilaminar pellicle, an apical complex formed by a conoid, polar rings, rhoptries, and micronemes, in addition to dense granules and the endoplasmic reticulum. No crystalloid body was observed but various lipid and amylopectin granules were usually present in the cytoplasm of zoites. We observed a tendency of the endoplasmic reticulum of the host cell to be located near the parasitophorous vacuole membrane. Merozoites were formed by endodyogeny and during replication, the apical complex of the mother cell remained intact. The formation of gametes or oocysts was not observed. The ultrastructural findings of C. belli are further evidence of its proximity to Sarcocystidae family members and corroborate their reclassification as Cystoisospora spp.

Enteric Parasitic Infections in Relation to Diarrhoea in HIV Infected Individuals with CD4 T Cell Counts <1000 Cells/μl in Chennai, India

AIM

This study was conducted to estimate the prevalence of enteric parasites in HIV patients in Chennai and to correlate with CD4 counts and diarrhoeal status.

MATERIAL AND METHODS

Faecal specimens from 100 HIV infected individuals with CD4 < 1000/μl were screened for enteric parasites with wet mounts, modified acid-fast stain for coccidian parasites, modified trichrome stain for Microsporidia, before and after the stool concentration. Agar plate culture for Strongyloides was put up. Chi-square and ANOVA tests were used for statistical analysis.

RESULTS

Study group comprised of 38 subjects with acute diarrhoea, 30 with chronic diarrhoea (> 2 weeks) and remaining 32 without diarrhoea. Enteric parasites were detected in 33% of subjects; Isoapora belli (21) being the commonest followed by E.histolyt/Entamoeba dispar (5), Entamoeba coli (2), Cryptosporidium spp (2), Hookworms (2), Strongyloides stercoralis (2), Giardia lamblia (1) and Microsporidium spp (1). There was a significant inverse relation between CD4 counts and duration of diarrhoea. Opportunistic parasites were isolated from the subjects with wide range of CD4 counts and different diarrhoeal status but most commonly from chronic diarrhoea patients.

CONCLUSION

The prevalence of intestinal parasitic infections in HIV patients is high in Chennai, India, especially at CD4 <1000/μl, I.belli infection being the commonest. Routine screening of all HIV patients with low CD4 counts for coccidian parasitic infections by using simple stool microscopic techniques can help in early diagnosis and treatment.

Prevalence of isosporiasis in relation to CD4 cell counts among HIV-infected patients with diarrhea in Odisha, India

BACKGROUND

To determine the prevalence of Isospora belli and its correlation with CD4+ cell counts in HIV-positive patients with diarrhea in this region.

MATERIALS AND METHODS

Stool samples from 250 HIV-positive patients, including 200 with diarrhea and 50 without diarrhea included in the study were examined for the presence of enteric parasites under microscopy. Prevalence of the enteric parasites with special reference to I. belli in HIV-positive patients with and without diarrhea were calculated and correlated with their CD4+ cell counts.

RESULTS

Enteric parasites were detected in 39% of the HIV patients with diarrhea compared to 30% without diarrhea. I. belli was detected in 22% of the patients with diarrhea and in 4% without diarrhea (P = 0.0019). I. belli was the most common parasite, followed by Entamoeba histolytica/dispar (8%) and Cryptosporidium parvum (5%) in HIV-positive patients with diarrhea. In HIV-positive patients without diarrhea, the most common parasite detected was E. histolytica/dispar (12%) followed by C. parvum (6%) and I. belli (4%). The mean CD4 cell count of HIV-positive patients with diarrhea suffering from isosporiasis was 138.35 ± 70.71. In patients with CD4 cell counts <200/μl, I. belli was seen in 36/123 stool samples and 2/27 stool samples which was statistically significant (P = 0.0157).

CONCLUSION

I. belli was the predominant parasite with a prevalence of 22% among HIV-positive patients with diarrhea, majority having CD4 cell count <200/μl. This study highlights the importance of routine screening for coccidian parasites in HIV-positive patients with and without diarrhea especially in those with low CD4 cell counts.

Isospora belli Infection with Chronic Diarrhea in an Alcoholic Patient

Chronic diarrhea with a 35 kg weight loss (75 kg to 40 kg) occurred during 2 years in an alcoholic patient was diagnosed with Isospora belli infection in the Republic of Korea. The patient, a 70-year old Korean male, had been a heavy drinker for more than 30 years. He was admitted to the Seoul National University Hospital because of long-standing diarrhea and severe weight loss. He had an increased white blood cell (WBC) count with high peripheral blood eosinophilia (36.8-39.9%) and lowered protein and albumin levels but without any evidence of immunosuppression. A parasitic infection was suspected and fecal examination was repeated 3 times with negative results. Peroral endoscopy with mural biopsy was performed in the upper jejunum. The biopsy specimens revealed villous atrophy with loss of villi together with various life cycle stages of I. belli, including trophozoites, schizonts, merozoites, macrogamonts, and microgamonts. The patient was treated successfully with oral doses of trimethoprim 160-320 mg and sulfamethoxazole 800-1,600 mg daily for 4 weeks. A follow-up evaluation at 2.5 years later revealed marked improvement of body weight (68 kg), increased protein and albumin levels, and normal WBC count with low eosinophils (3.1%). This is the first clinical case of isoporiasis with demonstration of various parasitic stages in the Republic of Korea.

Enteric spore-forming opportunistic parasites in HIV / AIDS

Human Immunodeficiency Virus (HIV) infection causes progressive damage to both limbs of the immune system, which results in a plethora of opportunistic infections. Among the various opportunistic infections, gastrointestinal infections are very common in HIV / Acquired Immunodeficiency Syndrome (AIDS). Opportunistic spore-forming protozoal parasites, namely, Cryptosporidium parvum, Isospora belli, Cyclospora cayetanensis, and Microsporidia, play a major role in causing chronic diarrhea, accompanied with weight loss, in patients with HIV / AIDS. The purpose of this review is to discuss the salient microbiological, clinical, and diagnostic aspects of important enteric spore-forming opportunistic parasites in HIV / AIDS.

Isospora belli associated recurrent diarrhea in a child with AIDS

Persistent diarrhea is a major manifestation of Acquired Immunodeficiency Syndrome (AIDS) which might be more complicated in Human Immunodeficiency Virus (HIV) infected children especially those from developing countries. There are numerous reports showing the emergence of intestinal opportunistic coccidian parasites, mostly Cryptosporidium parvum and Isospora belli in HIV-infected individuals. The prevalence of isosporiasis is probably underestimated in developing countries because routinely not all HIV-infected patients are examined for the presence of this protozoan infection. Here we report a case of HIV-infected isosporiasis presenting with failure to thrive and persistent diarrhea. Since I. belli infection in children responds well to therapy with trimethoprim-sulfamethoxazole, isosporiasis should be considered as a treatable infection in AIDS, if it is detected at proper time.

Opportunistic parasites among immunosuppressed children in Minia District, Egypt

A total of 450 stool samples were collected from inpatient and outpatient clinics of Pediatric Department, Minia University Hospital, Minia District, Egypt. Two groups of patients were studied, including 200 immunosuppressed and 250 immunocompetent children. Stool samples were subjected to wet saline and iodine mounts. A concentration technique (formol-ether sedimentation method) was carried out for stool samples diagnosed negative by wet saline and iodine mounts. Samples were stained by 2 different methods; acid fast stain (modified Ziehl-Neelsen stain) and Giemsa stain. Total 188 cases (94%) were diagnosed positive for parasitic infections among immunosuppressed children, whereas 150 cases (60%) were positive in immunocompetent children (P<0.0001). The most common protozoan infection in immunosuppressed group was Cryptosporidium parvum (60.2%), followed by Blastocystis hominis (12.1%), Isospora belli (9.7%), and Cyclospora caytenensis (7.8%). On the other hand, Entamoeba histolytica (24.6%) and Giardia lamblia (17.6%) were more common than other protozoans in immunocompetent children.

Isosporiasis in HIV/AIDS Patients in Edo State, Nigeria

BACKGROUND

The role of opportunistic infections in accelerating disease progression in HIV-positive individuals, leading to quick death, is still receiving serious attention. The objective of this study was to determine the prevalence of Isospora belli infections in HIV-positive patients in Edo State, Nigeria between August 2007 and March 2008.

METHODS

A total of 268 samples from HIV-positive patients and 20 samples from HIV-negative patients were processed using the modified Ziehl-Neelsen staining technique to microscopically identify the presence of I. belli oocysts.

RESULTS

The overall prevalence of the coccidian was 3.1%. Gender and age had no correlation with the prevalence of the parasite (P > 0.05). There was a significant relationship between isosporiasis and CD4+ T cell counts in HIV-positive patients (OR=11.388, 95% CI= 2.797-46.371, P=0.0004).

CONCLUSIONS

Routine investigation of I. belli in HIV-positive subjects is advocated in tertiary health institutions.