Prevalence and molecular characterization of Entamoeba moshkovskii in diarrheal patients from Eastern India

A New Multiplex PCR Assay Reveals the Occurrence of E. bangladeshi alongside E. histolytica and E. moshkovskii in Eastern India

PURPOSE

Epidemiological studies on amoebic infections are complicated due to morphologically identical and clinically important Entamoeba species. Therefore, newer, simpler, and more economical diagnostic techniques are required for differentiating clinically important Entamoeba species.

METHODS

We developed a single-round multiplex PCR assay to identify E. histolytica, E. moshkovskii, E. dispar, E. bangladeshi, and E. coli. Primers were designed based on variations in 18 S rRNA sequences. Sensitivity and specificity were assessed using known positive and negative samples. Furthermore, we screened 472 diarrheal samples using this technique alongside the reference PCR method to evaluate its suitability for epidemiological studies and clinical diagnosis. DNA sequencing and phylogenetic analysis of the isolates were conducted. All statistical analyses of the data were performed using GraphPad Prism.

RESULTS

The designed primers successfully yielded species-specific PCR products of different sizes as expected. We did not observe any non-specific amplifications of the primer set. The diagnostic performance was also convincing. After screening clinical samples using the method, we observed that 2.33% (n = 11) tested positive for E. moshkovskii, 1.06% (n = 5) tested positive for E. histolytica, and 0.85% (n = 4) tested positive for E. bangladeshi in the studied area. DNA sequencing further confirmed the identified species. The constructed phylogenetic tree also demonstrated clear separation of the detected species lineages.

CONCLUSION

The study suggests the multiplex PCR assay could be a reliable diagnostic tool for amoebic infections. This study is particularly significant as it marks the first reported occurrence of E. bangladeshi since its documentation in South Africa and its native Bangladesh.

Entamoeba moshkovskii as a potential model organism for Gal/GalNAc lectin intermediate subunit exhibition and functional identification

In humans, Entamoeba histolytica is the main pathogen causing various amoebiases, while E. moshkovskii falls between being a pathogen and non-pathogen. The two species have similar behavior patterns but differ significantly in pathogenicity, with previous studies and clinical data indicating that E. moshkovskii has a low level of pathogenicity. Meaningfully, the biological characteristics of E. moshkovskii make it a potential model organism and a protein display platform for studying the functions of important Entamoeba proteins. Here, an Amoeba-pcDNA3.1 vector capable of overexpressing E. histolytica-sourced Igl-C protein was constructed and successfully transfected into E. moshkovskii. High levels of expression of the Igl-C, EGFP, and NeoR genes were identified in Igl-C-transfected trophozoites using qRT-PCR, and they were subsequently confirmed using immunoblotting. Transfection of Igl-C protein improved the adherence and phagocytosis of E. moshkovskii, demonstrating that E. histolytica Igl mediated amoebic adhesion. Moreover, as a manifestation of protein virulence, the ability of post-transfected trophozoites to induce inflammation in host macrophages was also enhanced. In conclusion, this study utilizing the characteristics of E. moshkovskii confirmed its potential to serve as a model organism. E. moshkovskii could replace E. histolytica as the target of gene editing, allowing more efficient study of amoebic pathogenicity.

Food and Drinking Water as Sources of Pathogenic Protozoans: An Update

This narrative review was aimed at collecting updated knowledge on the risk factors, illnesses caused, and measures for the prevention of protozoan infections transmitted by food and drinking water. Reports screened dated from 2019 to the present and regarded global prevalence in food handlers, occurrence in food and drinking water, impact on human health, and recently reported outbreaks and cases of severe infections attributable to the dietary route. Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, and Cystoisospora belli were the protozoans most frequently involved in recently reported waterborne and foodborne outbreaks and cases. Blastocystis hominis was reported to be the most widespread intestinal protozoan in humans, and two case reports indicated its pathogenic potential. Dientamoeba fragilis, Endolimax nana, and Pentatrichomonas hominis are also frequent but still require further investigation on their ability to cause illness. A progressive improvement in surveillance of protozoan infections and infection sources took place in developed countries where the implementation of reporting systems and the application of molecular diagnostic methods led to an enhanced capacity to identify epidemiological links and improve the prevention of foodborne and waterborne protozoan infections.

Occult Amebiasis among Pediatric with Enterocolitis in National Referral Hospital in Indonesia

BACKGROUND

Enterocolitis and gastroenteritis remain major health problems, particularly in children living in developing countries. Intestinal protozoa, such as Entamoeba histolytica, Blastocystis, and Cyclospora, are frequently associated with these conditions. Amebic colitis can cause serious complications, including fulminant necrotizing colitis, toxic megacolon, extraintestinal amebiasis, and stunting in children. The diagnosis of amoebiasis is challenging, relying on microscopic examination, which cannot distinguish E. histolytica from the nonpathogenic E. dispar and E. moshkovskii. Therefore, this study aimed to identify intestinal parasites, particularly Entamoeba, their prevalence, and the clinical characteristics of patients admitted for enterocolitis and gastroenteritis at a tertiary-referral hospital.

MATERIAL AND METHODS

A cross-sectional, retrospective study was conducted at a national, tertiary-referral government hospital, in Jakarta. Of the 111 retrieved medical records from hospitalized patients with enterocolitis and gastroenteritis, for which parasitology feces were examined, 54 fecal samples (48.6%) were still available in the parasitology laboratory storage. All fecal samples underwent the following tests: 1) direct stool examination, after staining with 1% Lugol's solution, and using the water-ether concentration method; 2) modified acid-fast staining for coccidian parasites; 3) Jones' culture medium to detect Blastocystis; 4) copro-antigen assay to detect Cryptosporidium and Giardia; and 5) a polymerase chain reaction (PCR) assay to identify Entamoeba. Clinical and demographic data were obtained from the medical records.

RESULTS

Largely, patients (44.1%) were from the cohort of young children ≤5 years old, followed by adults aged 19-60 years old (24.3%). Both cohorts exhibited polyparasitism. Intestinal parasites were detected in 17 out of the 54 samples (31.4%). These included 6 (11.1%), 2 (3.7%),5 (9.2%), 3 (5.5%), 2 (3.7%), and 1 (1.8%) samples that were positive for Blastocystis, E dispar, E. histolytica, E. moshkovskii, Cryptosporidium, and Dientamoeba fragilis, respectively. PCR analysis revealed that 10 samples were positive for Entamoeba infection, eight of which originated from pediatric patients.

CONCLUSION

At a national tertiary-referral hospital in Indonesia, Entamoeba infection was the most prevalent parasite among pediatric patients with enterocolitis. E. histolytica and E. moshkovskii were the two main species identified by PCR. Therefore, PCR assays and fecal occult-blood tests are recommended in cases of enterocolitis and gastroenteritis.

Genetic characterization of the Entamoeba moshkovskii population based on different potential genetic markers

Entamoeba moshkovskii, according to recent studies, appears to exert a more significant impact on diarrhoeal infections than previously believed. The efficient identification and genetic characterization of E. moshkovskii isolates from endemic areas worldwide are crucial for understanding the impact of parasite genomes on amoebic infections. In this study, we employed a multilocus sequence typing system to characterize E. moshkovskii isolates, with the aim of assessing the role of genetic variation in the pathogenic potential of E. moshkovskii. We incorporated 3 potential genetic markers: KERP1, a protein rich in lysine and glutamic acid; amoebapore C (apc) and chitinase. Sequencing was attempted for all target loci in 68 positive E. moshkovskii samples, and successfully sequenced a total of 33 samples for all 3 loci. The analysis revealed 17 distinct genotypes, labelled M1–M17, across the tested samples when combining all loci. Notably, genotype M1 demonstrated a statistically significant association with diarrhoeal incidence within E. moshkovskii infection (P = 0.0394). This suggests that M1 may represent a pathogenic strain with the highest potential for causing diarrhoeal symptoms. Additionally, we have identified a few single-nucleotide polymorphisms in the studied loci that can be utilized as genetic markers for recognizing the most potentially pathogenic E. moshkovskii isolates. In our genetic diversity study, the apc locus demonstrated the highest Hd value and π value, indicating its pivotal role in reflecting the evolutionary history and adaptation of the E. moshkovskii population. Furthermore, analyses of linkage disequilibrium and recombination within the E. moshkovskii population suggested that the apc locus could play a crucial role in determining the virulence of E. moshkovskii.

Development of nucleic acid lateral flow immunoassay for molecular detection of Entamoeba moshkovskii and Entamoeba dispar in stool samples

Entamoeba moshkovskii, recently known as a possible pathogenic amoeba, and the non-pathogenic Entamoeba dispar are morphologically indistinguishable by microscopy. Although PCR was used for differential diagnosis, gel electrophoresis is labor-intensive, time-consuming, and exposed to hazardous elements. In this study, nucleic acid lateral flow immunoassay (NALFIA) was developed to detect E. moshkovskii and E. dispar by post-PCR amplicon analysis. E. moshkovskii primers were labeled with digoxigenin and biotin whereas primers of E. dispar were lebeled with FITC and digoxigenin. The gold nanoparticles were labeled with antibodies corresponding to particular labeling. Based on the established assay, NALFIA could detect as low as 975 fg of E. moshkovskii target DNA (982 parasites or 196 parasites/microliter), and 487.5 fg of E. dispar target DNA (444 parasites or 89 parasites/microliter) without cross-reactivity to other tested intestinal organisms. After testing 91 stool samples, NALFIA was able to detect seven E. moshkovskii (87.5% sensitivity and 100% specificity) and eight E. dispar samples (66.7% sensitivity and 100% specificity) compared to real-time PCR. Interestingly, it detected three mixed infections as real-time PCR. Therefore, it can be a rapid, safe, and effective method for the detection of the emerging pathogens E. moshkovskii and E. dispar in stool samples.

Genotyping and epidemiological distribution of diarrhea-causing isolates of Giardia duodenalis in southeastern part of West Bengal, India

The prevalence and genetic diversity of the protozoan pathogen Giardia duodenalis have been extensively studied worldwide. There is currently a lack of data regarding the genetic variability of the organism in eastern India. Understanding the circulating genotypes and associated risk factors is crucial for effective planning and implementing control measures. Therefore, the objective of the study was to conduct an epidemiological study to determine the prevalence and identify the various genotypes present. This survey adds to our knowledge on the occurrence and distribution of Giardia genotypes in the studied region. The overall prevalence was found to be 6.8%. This parasitic infection was significantly associated with two age groups, i.e., >0-5 years and >5-12 years. Using a multilocus genotyping method, we genotyped 52 human Giardia isolates that were obtained from diarrheal patients. Two distinct assemblages were found in the population-30.8% belonged to assemblage A; 63.5% belonged to assemblage B, prevalent in the population; and 5.7% belonged to a combined assemblage A+B. Sub-assemblage AII was found in 17.3% of the cases, followed by sub-assemblage AI (13.5%). High levels of genetic diversity were found within the population of assemblage B undergoing balancing selection. Overall, the high prevalence of the parasite observed, particularly among children, raises a major concern and necessitates implementation of robust control measures. Furthermore, we report the presence of numerous unique genotypes, circulating in this limited geographical boundary, which can be useful dataset for future studies.