Genetic diversity and molecular diagnosis of Giardia

Prevalence and genotypic identification of Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi in farmed ostriches (Struthio camelus) by the Yellow River in Zhengzhou city, central China

BACKGROUND

Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are significant zoonotic protozoa causing gastrointestinal diseases in humans and animals. However, their prevalence and genotypic characterization in ostriches (Struthio camelus) remain poorly understood. This study aimed to investigate the occurrence and genetic diversity of these parasites in farmed ostriches by the Yellow River in Zhengzhou City, central China. A total of 156 fecal samples were collected and analyzed using polymerase chain reaction (PCR) to determine the prevalence and assess the potential epidemiological roles of ostriches in transmission.

RESULTS

The overall prevalence of Cryptosporidium spp., G. duodenalis and E. bieneusi was 2.56% (4/156), 1.28% (2/156) and 12.2% (19/156), respectively. C. baileyi and G. duodenalis assemblage B were identified in ostriches. Six E. bieneusi genotypes were identified in this study, comprising four previously reported genotypes (EbpA, EbpC, Henan-IV, and Type IV) and two novel genotypes (designated as COW1 and COW2, which differed from known genotypes by two single nucleotide polymorphisms). Among these, EbpC was identified as the predominant genotype. All six genotypes were phylogenetically assigned to zoonotic group 1.

CONCLUSIONS

Our findings suggest that ostriches harbor zoonotic genotypes of G. duodenalis and E. bieneusi, indicating they may serve as potential reservoirs for human infection. This underscores the need for effective control measures to prevent environmental contamination and reduce the risk of transmission to humans and other animals.

Molecular characterization and risk analysis of Giardia duodenalis assemblages in corticosteroid-treated and non-treated patients in Ismailia, Arab Republic of Egypt

BACKGROUND

Giardia duodenalis (G. duodenalis) is an intestinal protozoan parasite of human and animal hosts. The present study investigated and compared the assemblages of G. duodenalis-infected faecal samples in patients on corticosteroid therapy (POCT) and control patients-not on corticosteroid therapy (CONT) and differentiated its assemblages and/or sub-assemblages' relationship with associated risk factors.

METHODS

Utilizing multi-locus sequence typing (MLST) with three loci targeted-triosephosphate isomerase (tpi), ꞵ-giardin (bg), and glutamate dehydrogenase (gdh)-G. duodenalis isolated from POCT and CONT were analyzed. Risk factors linked with Giardia infection and its assemblages were investigated.

RESULTS

In total, 52 G. duodenalis-infected patients were enrolled: 21 POCT and 31 CONT. The mean age was 12.3 years, the majority were male (59.6%), and 73.1% lived in rural areas. The POCT group was 36 times more likely than the CONT group to have a concurrent parasitic infection. About 73% (38/52) of Giardia samples were genotyped and/or sub-genotyped in at least one of the three loci. MLST identified sixteen isolates (42.0%) as assemblage B, ten isolates (26.3%) as assemblage A, and twelve isolates (31.6%) as a mixed infection of A + B and B + E. Most individuals of the POCT group were infected with G. duodenalis assemblage A while most of the CONT group were infected with assemblage B. Sub-assemblage AII was identified by phylogenetic analysis in the isolates of both groups under investigation.

CONCLUSION

This research advances giardiasis epidemiology in Arab Republic of Egypt (ARE) and reflects how corticosteroid-treated patients differ from those non-treated in Giardia assemblage pattern and their susceptibility to concomitant infection. Overall, Giardia assemblage patterns in this research populations reflect anthroponotic and zoonotic transmission, emphasizing the importance of public health policy and giardiasis prevention of illness transmission, particularly among those on corticosteroid therapy in ARE.

A rapid economical multiplex PCR-RFLP method for molecular detection and genotyping of Giardia duodenalis clinical isolates

Giardia duodenalis is a common cause of diarrheal illness in regions with limited resources. The demand for rapid and cost-effective detection and genotyping methods in large-scale epidemiological studies and clinical diagnostics is imperative. Hence, we developed a multiplex PCR-RFLP technique targeting the tpi gene of G. duodenalis. The assay successfully screened G. duodenalis positive clinical samples (6.33 %; 36/565). It was also able to categorize the isolates into assemblages A (41.66 %; 13/36) and B (58.33 %; 23/36), as well as into subassemblages: AI (13.8 %; 5/36), AII (27.77 %; 10/36), BIII (36.11 %; 15/36) and BIV (22.22 %; 8/36). High diagnostic sensitivity (94.2 %), specificity (100 %) and accuracy (97.1 %) of the PCR assay were obtained, indicating its reliability for diagnosing giardiasis. Notably, the assay demonstrated close concordance with microscopy (κ=0.85) and reference PCR (κ=0.98) results. The optimized method offers a cost-effective and rapid approach for G. duodenalis detection and genotyping, convenient for epidemiological studies and clinical diagnostics.

The Low Genetic Diversity of Dientamoeba fragilis Isolates in Southwest Turkey and Analysis of Clinical Findings

PURPOSE

Dientamoeba fragilis (D. fragilis) is a common intestinal protozoan with a global distribution. In the present study, we aimed to determine genetic diversity of D. fragilis isolates with multilocus sequence typing (MLST) in the southwest of Turkey and analyse the clinical findings.

MATERIALS AND METHODS

The study included faecal samples from 200 individuals in Aydin, Turkey. The positivity of D. fragilis was determined with 18 S rRNA gene-based PCR assay. Six nested-PCR reactions were set to amplify partial D. fragilis housekeeping genes in the positive samples. The sequences were aligned with the references from GenBank to detect nucleotide polymorphisms and haplotypes. Additionally, the clinical findings and demographic characteristics of patients were statistically analysed between D. fragilis-infected and non-infected cases.

RESULTS

The positivity of D. fragilis was 16% (32 out of 200 cases) with 18 S rRNA based-PCR, and all were classified as "genotype 1". The analysis of six MLST loci revealed different haplotypes only at one locus; the remaining five loci exhibited no polymorphisms. The haplotypes in the present study were identical to at least one previously reported reference, except the locus "large subunit of RNA polymerase II" locus. There were no significant differences in any of the clinical findings or demographic characteristics between the infected and non-infected groups.

CONCLUSIONS

Our study revealed a low genetic diversity of D. fragilis isolates from Turkey, like other countries including Italy, Denmark, the UK, Australia, and Brazil. The high degree of sequence similarity in housekeeping genes indicated the clonal distribution of D. fragilis.

Assemblage characterization of Giardia duodenalis in South Khorasan province, eastern Iran, using HRM real-time PCR method

BACKGROUND

Giardia duodenalis is a common parasitic protozoan causing gastrointestinal illness in humans worldwide. The genetic diversity of G. duodenalis is reflected through the identification of different assemblages. In this study, we aimed to determine the assemblages of G. duodenalis in eastern Iran using nested-PCR and high-resolution melting (HRM) real-time PCR methods.

METHODS

A total of 58 positive G. duodenalis, which were isolated from 1800 subjects, referred to medical center laboratories in South Khorasan province, eastern Iran, from April 2020 to March 2022, were included in this study. DNA was extracted and HRM real-time PCR was performed for assemblage characterization.

RESULTS

HRM real-time PCR successfully characterized all samples. Accordingly, out of 58 positive samples, 53 (91.36%) and 5 (8.62%) were identified as assemblage A and B, respectively.

CONCLUSIONS

Our findings showed that HRM real-time PCR was able to characterize the assemblages of G. duodenalis. In addition, our results suggest high prevalence of assemblage A in eastern region of Iran.

Molecular appraisal of Giardia intestinalis from Western India: A prospective observational study

Background

Giardia intestinalis is an intestinal protozoan which commonly causes parasitic gastroenteritis globally. It is a species complex consisting of at least eight assemblages (genotypes). In India, Giardia is mostly underreported and missed in asymptomatic cases.

Aim

The aim of this study was to genotype the G. intestinalis isolates from stool samples of patients at a tertiary care center in Rajasthan, India, and to clinically correlate it.

Methods

This prospective pilot cross-sectional study was conducted from 2019 to 2021 in a tertiary care center in western India. Patients who were microscopically positive for giardiasis were enrolled. DNA was extracted from their stool samples and amplified by polymerase chain reaction (PCR) using 4E1-HP as the target sequence. Anthropometric measurements and analysis were done for children by using Anthrocal application.

Results

A total of 50 patients were enrolled. Diarrhea was present in 18 patients (36%). Among these, 6 were immunocompromised and had different comorbidities. Among the children <12 years of age, 55.17% (n = 16/29) were stunted (<-2 S.D.), and among <5 years, 44.4% (n = 4/9) showed wasting (<-2 S.D.). A PCR product corresponding to assemblage B of G. intestinalis was amplified in 47 stool specimens. Only three stool samples were negative for both assemblages A and B and posed an interesting enigma.

Conclusion

In this study, a predominance of assemblage B of G. intestinalis was detected in 94% of the isolates. Furthermore, the possibility of zoonotic transmission could not be ruled out.