Simultaneous detection and differentiation of Entamoeba histolytica, E. dispar, E. moshkovskii, Giardia lamblia and Cryptosporidium spp. in human fecal samples using multiplex PCR and qPCR-MCA

A rapid multiplex loop-mediated isothermal amplification (mLAMP) assay for detection of Entamoeba histolytica and Giardia duodenalis

We developed a rapid multiplex loop-mediated isothermal amplification (mLAMP) assay for two common intestinal parasites-Entamoeba histolytica and Giardia duodenalis, where early detection may be helpful. The mLAMP assay was optimized for the detection of DNA of E. histolytica (18S rRNA gene) and G. duodenalis (Elongation factor 1 alpha gene) from standard strains by using six specific primers FIP (forward inner primer), BIP (backward inner primer), F3 (forward outer primer), B3 (backward outer primer), loopF (forward loop primer), and loopB (backward loop primer) for each gene target. The amplification time was 16-26 min for E. histolytica and 10-15 min for G. duodenalis, and the parasites could be distinguished based on melting-curve analysis for specific annealing temperatures (Tm) of 84°C-86°C and 88°C-90°C for E. histolytica and G. duodenalis, respectively. The analytical sensitivity was one fg, and no cross-reactivity with other intestinal pathogens was observed. Thus, the mLAMP assay could detect and clearly distinguish E. histolytica and G. duodenalis with a rapid turnaround time and excellent analytical sensitivity and specificity.

Prevalence and Molecular Identification of Entamoeba spp. in Non-human Primates in a Zoological Garden in Nanjing, China

Objective

Entamoeba spp. are globally distributed zoonotic parasites that infect various hosts, among which non-human primates (NHPs) have been identified as one of the most common hosts of these parasites. Consequently, the infections of Entamoeba spp. in captive NHPs from Nanjing Hongshan Forest Zoo in China were investigated in order to assess their zoonotic potential.

Methods

A total of 120 fresh fecal samples, including 19 species of NHPs, were collected from four breeding bases of the zoo from May to June 2019. The infections of six species of Entamoeba spp. were detected by PCR using the 16S or 18S rDNA-specific primers, and the positive samples were sequenced and analyzed.

Results

Entamoeba spp. were detected as positive in 59 NHPs fecal samples (49.17%), including five Entamoeba species: Entamoeba histolytica (7.50%), E. dispar (22.50%), E. coli (22.50%), E. chattoni (10.00%) and E. nuttalli (1.67%). Infection with one Entamoeba species was more common (35%) than co-infections (13.33%) or infections with three Entamoeba species (0.83%). There was a significantly higher prevalence rate of Entamoeba spp. in the species Pongo pygmaeus and Macaca mulatta than in Papio sp., Mandrillus sphinx, and Saimiri sciureus.

Conclusion

Entamoeba spp. are highly prevalent in the NHPs raised in Nanjing Hongshan Forest Zoo. Therefore, attention should be paid to the development of containment strategies of Entamoeba spp. in this zoological garden.

Development of HRM real-time PCR for assemblage characterization of Giardia lamblia

A total of 90 stool samples were collected from dogs, referred to a dog shelter and a veterinary clinic. In addition, 395 stool samples obtained from pet dog owners and shelter keepers, as well as individuals referred to a medical laboratory as controls, were collected in Shahryar district, Tehran, Iran. Stool samples were parasitologically examined and the positive G. lamblia isolates were tested with Nested-PCR/sequencing for the tpi, gdh, and bg genes, and HRM real-time PCR. Microscopical examination revealed 20 (22.2%) and 34 (8.6%) Giardia-positive samples from dogs and humans, respectively. Regarding HRM real-time PCR, the prevalence of assemblages A and B in humans was 55.8% and 14.7%, respectively. In addition, 14.7% of samples were mix assemblages. HRM real-time PCR detected most of microscopically-positive samples in comparison to PCR/sequencing in both humans and dogs. The high prevalence of assemblages A and B in dogs signified the importance of a same source for infection between dogs and humans.

Comparison of Three Real-Time PCR Assays Targeting the SSU rRNA Gene, the COWP Gene and the DnaJ-Like Protein Gene for the Diagnosis of Cryptosporidium spp. in Stool Samples

As qualified microscopy of enteric parasitoses as defined by high diagnostic accuracy is difficult to maintain in non-endemic areas due to scarce opportunities for practicing with positive sample materials, molecular diagnostic options provide less investigator-dependent alternatives. Here, we compared three molecular targets for the real-time PCR-based detection of Cryptosporidium spp. From a population of 1000 individuals comprising both Ghanaian HIV (human immunodeficiency virus) patients and military returnees after deployment in the tropics, stool samples were assessed for Cryptosporidium spp. by real-time PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene, the Cryptosporidium oocyst wall (COWP) gene, and the DnaJ-like protein gene (DnaJ), respectively. In declining order, sensitivity of 100% for the SSU rRNA gene PCR, 90.0% for the COWP PCR and 88.8% for the DnaJ PCR, respectively, as well as specificity of 99.6% for the COWP PCR and 96.9% for both the SSU rRNA gene PCR and the DnaJ PCR, respectively, were recorded. Substantial agreement (kappa value 0.663) between the three assays was observed. Further, an accuracy-adjusted Cryptosporidium spp. prevalence of 6.0% was calculated for the study population. In conclusion, none of the assessed real-time PCR assays were associated with perfect test accuracy. However, a combination of highly sensitive SSU rRNA gene PCR for screening purposes and more specific COWP PCR for confirmatory testing should allow reliable diagnosis of Cryptosporidium spp. in stool samples even in low prevalence settings.

Multiplexed digital polymerase chain reaction as a powerful diagnostic tool

The digital polymerase chain reaction (dPCR) multiplexing method can simultaneously detect and quantify closely related deoxyribonucleic acid sequences in complex mixtures. The dPCR concept is continuously improved by the development of microfluidics and micro- and nanofabrication, and different complex techniques are introduced. In this review, we introduce dPCR techniques based on sample compartmentalization, droplet- and chip-based systems, and their combinations. We then discuss dPCR multiplexing methods in both laboratory research settings and advanced or routine clinical applications. We focus on their strengths and weaknesses with regard to the character of biological samples and to the required precision of such analysis, as well as showing recently published work based on those methods. Finally, we envisage possible future achievements in this field.

A POTENTIAL ZOONOTIC PARASITE: CRYPTOSPORIDIUM PARVUM TRANSMISSION IN RATS, PIGS AND HUMANS IN WEST LOMBOK, INDONESIA

BACKGROUND

Cryptosporidium is a neglected zoonotic disease, but with the expansion of the human community into the animal environment, its incidence is increasing. Animals such as rats and pigs can act as intermediate hosts and transmit Cryptosporidium to humans due to their proximity. Transmission occurs due to the ability of Cryptosporidium to survive in any new host. The research aimed to identify and describe the transmission of Cryptosporidium from animals to humans.

MATERIALS AND METHODS

This research was a cross sectional study and samples were collected from 84 rats caught in residential areas, 205 pigs, and 438 humans in West Lombok. Fecal samples were examined using polymerase chain reaction (PCR) and sequencing to isolate the presence of Cryptosporidium, and identify the genetic similarity of the parasites found in rats and pigs with those that infect humans.

RESULTS

The PCR results found Cryptosporidium parvum in 4.76% (4/84) in rats; 6.34% 13/205) in pigs; and 0.91% (4/438) in humans. The sequencing results showed genetic kinship of C. parvum in rats, pigs, and humans. Based on sequence confirmation from Gene Banks and edited using ClustalW with MEGA X software, there are genetic similarities between Cryptosporidium isolates from West Lombok and C. suis isolates of cattle from Uganda and C. suis isolates of pigs from Slovakia.

CONCLUSION

There are genetic similarities of Cryptosporidium in animals and humans, requiring that the Public Health programs in those contaminated areas must receive priority attention to prevent further transmission of these potentially fatal parasites.

Molecular genotypes analysis of Cryptosporidium and Hymenolepis in rats on Lombok Island, Indonesia

Background and Aim: Cryptosporidium parvum and Hymenolepis nana are intestinal parasites that are commonly found in the unclean environment. Their presence in rats promotes the transmission of the cryptosporidiosis and hymenolepiasis to humans or animals nearby. This study aimed to determine the molecular characteristics of C. parvum and H. nana and their distribution in rats on Lombok Island. Materials and Methods: C. parvum and H. nana were investigated in 50 rats from Lombok Island. The molecular-parasitological technique used was polymerase chain reaction and sequencing method. Results: From 50 samples of rats' stool from 10 locations on Lombok Island, 8% (4/50) of C. parvum was detected molecularly with an 18S rRNA gene and 2% (1/50) of H. nana with COX 1 gene. Phylogenetic analysis indicated that C. parvum carrying rats on Lombok Island have a genetic relationship with C. parvum with Obi7 isolates, Japan and H. nana has a genetic relationship with Rodentolepis nana identified with Hn-VT isolates, India. Conclusion: The highest incidence of parasites was found in rats that were caught in the urban areas of Lombok Island, West Nusa Tenggara, Indonesia. Immediately, public health programs in these types of contaminated areas should receive priority attention to prevent further transmission of the parasites from animals to human beings.

Enteric parasitic infection disturbs bacterial structure in Mexican children with autoantibodies for type 1 diabetes and/or celiac disease

Background

Intestinal bacterial dysbiosis and increased gut permeability are associated with higher risk of developing type 1 diabetes (T1D) or celiac disease (CD). There is a lack of information on parasitism involved in gut disturbance of predisposed children. We evaluated the effect of enteropathogenic parasites (Cryptosporidium spp., Cyclospora spp. G. lamblia, and Blastocystis spp.) on the bacterial structure of feces from children with autoantibodies for T1D or CD. Participants included 37 children under 18 years of age, from whom stools were analyzed for enteric parasites by qPCR and 22/37 for bacterial profile by sequencing the V3–V4 region of the 16s rRNA gene. Dietary, clinical, and socioeconomic data was recorded.

Results

Pathogens parasitized 28/37 participants, Cryptosporidium spp. was the most prevalent (62.2%), followed by both Cyclospora cayetanensis and Blastocystis spp (37.8%). There were no dietary differences (p > 0.05) attributable to parasitism. Co-infected participants with Cryptosporidium and Cyclospora did not differ (p = 0.064) from non-infected participants in bacterial alpha phylogenetic diversity. The same parasites’ co-infection was associated with a decreased abundance of the Ruminococaceae (p = 0.04) and Verrucomicrobioceae families, of the Akkermansia genus (p = 0.009). There was a lower Firmicutes/Bacteroidetes ratio (p = 0.02) in infected than in uninfected participants.

Conclusions

Cryptosporidium and Cyclospora affected the bacterial structure at family and genus levels, decreasing the ratio between Firmicutes and Bacteroidetes in children with auto-antibodies for T1D or CD, which could increase the risk of illness onset.

Molecular identification of Entamoeba histolytica from stool samples of Ilam, Iran

INTRODUCTION

Amoebiasis is a multifactorial, life-threatening public health issue and the third parasitic disease cause of mortality in worldwide, particularly in low- and mid-income countries. The aim of this study was to attempt to explore genetic encoding differences of CP8 (conserved gene) of Entamoeba histolytica/Entamoeba dispar in its various infectious properties isolated from Ilam located at a southwest part of Iran.

MATERIALS AND METHODS

A total of 2023 stool samples were collected between 2016 and 2018 from the hospital in Ilam, of which only 30 isolates were identified as E. histolytica/E. dispar. These isolates were collected from the intensive care unit, infectious disease, and surgery settings. The isolates were identified and the polymerase chain reaction (PCR) was performed to detect the CP8 gene. In all stages, Entamoeba histolytica HM1: IMSS was used as a positive control.

RESULTS

In genotype confirmation, only two isolates had the CP8 gene found in the PCR technique. The sequencing results confirmed the mentioned gene with 99%-100% specificity.

CONCLUSION

It is concluded that PCR is highly sensitive to detect E. histolytica and indicating this important role as screening tools in direct DNA extraction from stool samples and valuable technique in early detection of symptomatic and asymptomatic E. histolytica patients.

Molecular diagnosis of Entamoeba spp. versus microscopy in the Great Cairo

Amoebiasis is a human disease produced by Entamoeba histolytica which causes widespread mortality and morbidity worldwide through diarrheal disease and abscess establishment in parenchymal tissues such as liver, lung, and brain. The true prevalence of infection is unknown for most areas of the world due to the difficulty to characterise Entamoeba histolytica versus other non-pathogenic amoebas with identical morphology, as Entamoeba dispar, and Entamoeba moshkovskii. To overcome microscopy misidentification issues, we tested a nested multiplex polymerase chain reaction (PCR) and a real-time PCR on 194 stool samples collected from incoming dysentery patients in Cairo hospitals diagnosed with E. histolytica by microscopy. Nested PCR showed only 20 (10.3%) samples positive to E. histolytica and 17 (8.7%) to E. dispar. The real-time PCR detected only 19 and 11 samples positive to E. histolytica and E. dispar respectively, showing less sensitivity than the nested PCR. The data show that prevalence of E. histolytica in Cairo is lower when specific diagnosis methods are used instead of traditional microscopy, allowing to differentiate between morphologically identical human amoebas species.