Prevalence, risk factors for infection and subtype distribution of the intestinal parasite Blastocystis sp. from a large-scale multi-center study in France

Blastocystis in humans and domestic animals: Risk factors assessment and potential zoonotic transmission in a periurban and rural region of Northeastern Argentina

Blastocystis is a protist that infects both human and animal hosts worldwide. This study aimed to investigate the presence of Blastocystis in humans and domestic animals living in a periurban (PZ) and rural zone (RZ) in Northeastern Argentina and to assess their relation to socio-environmental conditions and hygiene practices as risk factors for human infection. In addition, we identified Blastocystis subtypes to evaluate the risk of zoonotic transmission. A total of 563 fecal specimens were collected from 289 humans, principally children, and 274 animals. Samples were examined by coprological examination and further analysis by real-time PCR and sequencing were performed. A semi-structured questionnaire was applied to obtain socio-environmental and hygiene practices data. The results showed an overall prevalence of 41.6 % in children and 10.2 % in animals. Non-schooled children (OR = 0.54) and children from urban area (OR = 0.55) showed a lower risk of infection. Molecular analyses revealed five subtypes (ST1, ST2, ST3, ST5, and ST7) present in humans and four subtypes (ST1, ST5, ST7 and ST10) in animals. The overlap of STs between humans and domestic animals in the same household (STs 1, 5 and 7) suggests potential zoonotic transmission, underscoring the role of infected animals as a potential risk factor for human infections. Our results can inform local health authorities to promote policies aimed at reducing transmission, emphasizing the need for direct molecular-level assessments of other common environmental sources, such as water and soil, highlighting the importance of adopting a One Health approach to better understand Blastocystis circulation.

Edible plants as significant sources of Blastocystis spp. infections: A systematic review and meta-analysis

This systematic review and meta-analysis were conducted to comprehensively overview the global epidemiology and subtypes (STs) distribution of Blastocystis spp. in edible plants. A comprehensive search of various electronic databases (PubMed, Scopus, Google Scholar, and Web of Science) until May 19, 2024, found 27 studies/41 datasets meeting inclusion criteria, covering 8794 edible plants from 15 countries globally. Examined edible plants were composed of fruits (six datasets, 1198 samples), non-leafy green vegetables (10 datasets, 1158 samples), leafy green vegetables (18 datasets, 4245 samples), and uncategorized plants (seven datasets, 2193). This study revealed that 9.4 % (95 % CI: 6.6-13.4 %) of global edible plants harbored Blastocystis spp. Fruits had the highest Blastocystis spp. contamination rate among edible plants at 12.5 % (95 % CI: 5.4-26.6 %), followed by uncategorized plants at 10.2 % (95 % CI: 4.5-21.5 %), leafy green vegetables at 9.3 % (95 % CI: 6.1-13.9 %), and non-leafy green vegetables at 5.6 % (95 % CI: 2.5-12.1 %). Sensitivity analysis evaluated weighted prevalence changes after excluding specific studies. Subgroup analysis was conducted considering publication years, countries, continents, WHO regions, sample sizes, and diagnostic methods. Interestingly, zoonotic STs (ST1 and ST3) of Blastocystis spp. have been found in edible plants. These results highlight the potential risk of Blastocystis spp. transmission through consuming contaminated edible plants, emphasizing the importance of implementing adequate food safety measures to decrease the prevalence of this parasite in the food chain.

Intragenomic diversity of the small subunit rDNA gene shows limited impact on the pathogenicity of Blastocystis infection in clinical patients

The clinical significance of Blastocystis sp. remains to be fully elucidated. This study assesses whether Blastocystis subtype diversity can affect the outcome of the infection and the occurrence of clinical manifestations in infected individuals. Stool samples from 219 Blastocystis-positive patients by PCR targeting the ssu rDNA gene were fully genotyped by Sanger sequencing analyses. Co-infections by other parasitic, viral, and bacterial enteropathogens were identified by molecular and culture methods. Sequence analyses revealed the presence of six Blastocystis subtypes including ST1 (21.5 %), ST2 (17.8 %), ST3 (29.7 %), ST4 (22.8 %), ST6 (5.5 %), and ST7 (2.3 %), with a single sample harbouring a ST1+ST3 co-infection (0.5 %). Multivariate risk factor analyses using logistic regression models indicated that neither Blastocystis subtypes nor patient-associated variables including sex, country of origin, travelling history, and presence of nonspecific symptoms were positively associated with a higher likelihood of developing gastrointestinal symptoms (abdominal pain and diarrhoea). However, being of a young age (p-value: 0.003) and experiencing skin pruritus (p-value < 0.001) and eosinophilia (p-value: 0.016) were found to increase the odds of presenting gastrointestinal symptoms. Blastocystis subtypes based on variability within the ssu rDNA gene do not seem to be the main drivers of clinical manifestations in the surveyed clinical population.

Blastocystis and Giardia duodenalis infection in a male prison in Spain

Background

General conditions in a prison may facilitate water- or food-borne infections.

Methods

Detection of intestinal parasites was achieved in 471 male prison inmates by standard microscopic procedures on their stool samples. Positive samples were processed by PCR amplification of a 600-bp fragment of the Blastocystis SSU rRNA gene and partial sequences of the Giardia duodenalis bg genes. Identification of subtypes/genotypes was based on Sanger sequencing methods.

Results

Blastocystis was found in 7.9 % (37/471) and G. duodenalis was found in 2.1 % (10/471). Out of the 37 Blastocystis positive samples, 54 % (20/37) were successfully subtyped, allowing the identification of the subtypes ST3 (50 %), ST1 (25 %), ST2 (15 %), ST4 (5 %) and ST6 (5 %). Out of 10 G. duodenalis positive samples, 50 % (5/10) were successfully genotyped, allowing the identification of genotypes A (80 %) and B (20 %).

Conclusions

The predominance of ST3 within the prison inmates, together with its low intra-ST genetic variability, reflected inter-human transmission with spatial stability. The G. duodenalis distribution is not wide enough to consider the possibility of a generalized transmission via contaminated water or food. Personal hygiene practices among male prison inmates may be an important measure to prevent the transmission.

Current status of intestinal parasitosis and microsporidiosis in industrialized countries: Results from a prospective study in France and Luxembourg

BACKGROUND

Human intestinal parasitosis and microsporidiosis are a global health concern, mostly in endemic areas but should not be neglected elsewhere. Recent nationwide epidemiological data are scarce, especially from primary health care and developed countries. Diagnosis by molecular tools are increasing and several commercial gastrointestinal panel assays including protozoans and/or helminths are now available. These news tools improve the knowledge into real human parasite epidemiology. This study provides an epidemiological update on intestinal parasites found in primary health care in France and Luxembourg.

METHODOLOGY/PRINCIPAL FINDINGS

Two thousand fifty-six stools from primary health care patients were analyzed for the presence of intestinal parasites (IPs) during two different seasons of 2022, the winter and the summer, corresponding to more than 1500 patients from all over France and Luxembourg. Parasite detection was performed combining standard microscopy (merthiolate-iodine-formaldehyde and Bailenger concentration procedures) with two molecular panel assays (AMPLIQUICK Fecal Pretreatment, AMPLIQUICK Protozoans and AMPLIQUICK Helminths, BIOSYNEX, France). The prevalence of IPs in primary care patients reached 33.2%. Blastocystis sp. and Dientamoeba fragilis were the most frequently detected parasites in 20.5% and 13.1% of patients, respectively. Coinfection with two or more parasites was detected in 9.9% of patients. For some parasites, patterns according to gender, age, geography or season have been observed.

CONCLUSION/SIGNIFICANCE

The high prevalence of pathogenic IPs (about 7%) underlines the importance of investigating gastrointestinal disorders through parasite examination, even in developed countries. The detection of parasites, pathogenic or not, remains a marker of the faecal-oral route of transmission and results should be interpreted accordingly. Parasites molecular characterization give new insights and should encourage further research as industrialized countries are not exempt of parasitic circulation and a better survey is necessary.

A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos

Intestinal protists in the gut microbiome are increasingly studied, but their basic epidemiology is not well understood. We explored the prevalence, genetic diversity, and potential zoonotic transmission of two protists colonizing the large intestine - Blastocystis sp. and Dientamoeba fragilis - in 37 species of non-human primates (NHPs) and their caregivers in six zoos in the Czech Republic. We analyzed 179 fecal samples (159 from NHPs, 20 from humans) by qPCR. Blastocystis sp. was detected in 54.7% (98/179) of samples, in 24 NHP species and in 57.2% of NHP samples (prevalence ranged between 36 and 80%), and in 35% of human samples (prevalence ranged between 0 and 67%). Using next generation amplicon sequencing, nine Blastocystis subtypes (ST1-ST5, ST7, ST8, and two novel subtypes) were identified. The two new Blastocystis subtypes (named ST47 and ST48) were described using Nanopore sequencing to produce full-length reference sequences of the small subunit ribosomal RNA gene. Some subtypes were shared between NHPs and their caregivers, suggesting potential zoonotic transmission. Mixed subtype colonization was frequently observed, with 52% of sequenced samples containing two or more subtypes. Dientamoeba was found only in NHPs with a prevalence of 6%. This study emphasizes the critical role of molecular diagnostics in epidemiological and transmission studies of these protists and calls for further research to better understand their impact on public health.

Prevalence of Blastocystis infection in humans in Türkiye: A systematic review and meta-analysis

Although Blastocystis, a protozoan, is commonly found in all species of animals and in humans, there remains a lack of clear information about its epidemiology and routes of transmission. The aim of this meta-analysis study was to determine the changes in Blastocystis prevalence and subtype distribution in humans in Türkiye according to geographical regions. Databases were searched using the Web of Science, PubMed, Scopus, EBSCO, and TRDizin to identify studies on the prevalence of Blastocystis in humans in Türkiye published from 2009 to 2023. As a result of this systematic search, 117 of 730 articles were included in the meta-analysis. The pooled prevalence of human Blastocystis infection in Türkiye was 13.08 %. The prevalence of the pool was higher in the Black Sea region, which is the most humid region in Türkiye, than in other regions. Blastocystis subtypes were identified in a total of 885 positive samples. The most common subtypes (ST) in Türkiye were ST3, ST1 and ST2, respectively. In addition to these ST4, ST5, ST6 and ST7 were also detected in humans in Türkiye. In conclusion, the prevalence of Blastocystis in humans is high in Türkiye, especially in the Black Sea region.

Effective Laboratory Diagnosis of Parasitic Infections of the Gastrointestinal Tract: Where, When, How, and What Should We Look For?

(1) Introduction: Gastrointestinal parasites (GIPs) are one of the most common causes of disease in the world. Clinical diagnosis of most parasitic diseases is difficult because they do not produce characteristic symptoms. (2) Methods: The PubMed, Science Direct, and Wiley Online Library medical databases were reviewed using the following phrases: "parasitic infections and diagnostics", "intestinal parasites", "gastrointestinal parasites", "parasitic infections and diagnostics", and their combinations. (3) Results and Conclusions: Correct diagnosis of GIP involves determining the presence of a parasite and establishing a relationship between parasite invasion and disease symptoms. The diagnostic process should consider the possibility of the coexistence of infection with several parasites at the same time. In such a situation, diagnostics should be planned with consideration of their frequency in each population and the local epidemiological situation. The importance of the proper interpretation of laboratory test results, based on good knowledge of the biology of the parasite, should be emphasized. The presence of the parasite may not be causally related to the disease symptoms. Due to wide access to laboratories, patients often decide to perform tests themselves without clinical justification. Research is carried out using various methods which are often unreliable. This review briefly covers current laboratory methods for diagnosing the most common gastrointestinal parasitic diseases in Europe. In particular, we provide useful information on the following aspects: (i) what to look for and where to look for it (suitability of feces, blood, duodenal contents, material taken from endoscopy or biopsy, tissue samples, and locations for searching for eggs, cysts, parasites, parasite genetic material, and characteristics of immune responses indicating parasitic infections); (ii) when material should be collected for diagnosis and/or to check the effectiveness of treatment; (iii) how-that is, by what methods-laboratory diagnostics should be carried out. Here, the advantages and disadvantages of direct and indirect methods of detecting parasites will be discussed. False-positive or false-negative results are a problem facing many tests. Available tests have different sensitivities and specificities. Therefore, especially in doubtful situations, tests for the presence of the pathogen should be performed using various available methods. It is important that the methods used make it possible to distinguish an active infection from a past infection. Finally, we present laboratory "case reports", in which we will discuss the diagnostic procedure that allows for the successful identification of parasites. Additionally, we briefly present the possibilities of using artificial intelligence to improve the effectiveness of diagnosing parasitic diseases.

Blastocystis hominis as a cause of chronic diarrhea in low-resource settings: A systematic review

BACKGROUND

Blastocystis hominis (B. hominis), an anaerobic unicellular protist parasite, is known for its diverse clinical manifestations upon infecting the human gastrointestinal tract. Although globally distributed, it is particularly prevalent in developing nations. Examining the symptoms and treatment outcomes of B. hominis infection in low-resource settings holds immense significance, providing healthcare practitioners with valuable insights to enhance patient care.

AIM

To synthesize existing evidence on the symptomatology and treatment outcomes of B. hominis infection in low-resource settings.

METHODS

Following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, a systematic review was conducted. The search spanned electronic databases including PubMed, Scopus, and Google Scholar. After a comprehensive screening process, a thorough examination of the papers, adhering to inclusion and exclusion criteria, and data extraction from eligible studies was conducted. The findings underwent summarization through simple descriptive analysis.

RESULTS

The search yielded 1200 papers, with 17 meeting inclusion criteria. Chronic diarrhea due to B. hominis infection was reported in only two studies, while abdominal pain, diarrhea, flatulence, constipation, and nausea/vomiting emerged as the most commonly documented symptoms. Recovery rates after one week of treatment ranged from 71.8% to 100%, and after two weeks, from 60% to 100%.

CONCLUSION

In low-resource settings, chronic diarrhea resulting from B. hominis infection is infrequent. Common symptoms include abdominal pain, diarrhea, flatulence, constipation, and nausea/vomiting. Post-treatment, clinical outcomes are notably favorable, supporting the recommendation for treatment. Metronidazole is advocated as the first-line agent, with consideration for switching to a second-line option in cases of treatment failure or poor response.

Unveiling Blastocystis epidemiology in Morocco: subtype diversity among clinical patients with and without gastrointestinal manifestations in the Meknes region

Blastocystis is an intestinal protist frequently identified in humans and other animals, though its clinical significance remains controversial. This study aimed to determine the prevalence and genetic diversity of Blastocystis in faecal samples from symptomatic (n = 55) and asymptomatic (n = 50) individuals seeking medical care in Meknes, Morocco. Detection of the protist was accomplished through coproparasitological examination and culture in Jones medium. Culture-positive samples were subjected to molecular analyses (PCR and Sanger sequencing) based on sequences of the small subunit ribosomal RNA gene. Epidemiological questionnaires on demographics and potential risk factors were collected from participating patients. The overall Blastocystis infection rate was 51.4% (54/105), with no differences between symptomatic (52.7%, 29/55) and asymptomatic (50.0%, 25/50) individuals. Sequence analyses identified three Blastocystis subtypes, with ST3 being the most prevalent (42.0%), followed by ST1 (34.0%), and ST2 (12.0%). Regarding intra-subtype diversity, allele 4 was found within ST1; alleles 11/12 and alleles 34/36 (alone or in combination) were identified within ST2 and ST3 respectively. Allele 34 in ST3 (40.8%) and allele 4 in ST1 (34.7%) were the most common genetic variants circulating in the surveyed clinical population. A statistically significant association between ST2 and the presence of flatulence was observed. This is the first study assessing the epidemiology and genetic diversity of Blastocystis sp. in the Meknes region, Morocco.

Blastocystis colonization and associations with population parameters in Thai adults

BACKGROUND

Blastocystis is a unicellular eukaryote commonly found in the intestinal tract of humans and other animals. The prevalence of Blastocystis has been investigated in both developed and developing countries, yet its occurrence and distribution in rural locations has been less studied. Herein, we aimed to examine the distribution of Blastocystis colonization in Thai adults representing background populations along a rural/peri-urban gradient, as well as associations between colonization and personal characteristics.

METHODOLOGY

A total of 238 participants were recruited from rural and peri-urban areas situated in three provinces. The presence of Blastocystis in feces was evaluated using PCR and qPCR. Information on gender, age, region (province), rural/peri-urban location, and body mass index (BMI) was collected.

PRINCIPAL FINDINGS

The overall rate of Blastocystis carriage was 67.2%. Univariate analysis revealed significant associations between Blastocystis carriage and region (p<0.05), location (p<0.001) and age group (p<0.05). Logistic regression analysis revealed that rural/peri-urban location and BMI were significantly associated with Blastocystis carriage. Nine subtypes (ST1-ST7, ST10 and ST23) were identified with ST3, ST7 and ST1 as the most abundant ones, in this order. The greatest diversity of subtypes, in terms of numbers, was found in the middle aged group (nine subtypes), while the least diversity was found in the young adult and obese (three subtypes each) groups.

CONCLUSIONS

This study increases the understanding of the epidemiology of Blastocystis colonization and its association with population parameters and characteristics in middle-income countries.

Insights into parasites and COVID-19 co-infections in Iran: a systematic review

BACKGROUND

It is well-documented that using immunosuppressive drugs such as corticosteroids or cytokine blockers in treating coronavirus disease 2019 (COVID-19) increases the risk of co-infections. Here we systematically summarized the cases of COVID-19-associated parasitic infections (CAPIs) in Iran.

METHODS

From 19 February 2020 to 10 May 2023, all studies on Iranian patients suffering from CAPIs were collected from several databases using a systematic search strategy.

RESULTS

Of 540 records, 11 studies remained for data extraction. In this research, most of the studies were related to Lophomonas and Toxoplasma. Of 411 cases of CAPIs, toxoplasmosis (385 [93.7%]) had the highest rate of infection among Iranian patients, followed by blastocystosis (15 [3.6%]), fascioliasis (4 [0.97%]), leishmaniasis (3 [0.7%]), lophomoniasis (3 [0.7%]) and strongyloidiasis (1 [0.2%]). In general, Blastocystis enhanced diarrhoea in patients with COVID-19. Lophomonas, Toxoplasma and Strongyloides increased the severity of COVID-19, but Fasciola decreased its intensity. Patients with a history of cutaneous leishmaniasis showed mild symptoms of COVID-19. Also, patients with a prior history of hydatid cysts were not affected by COVID-19.

CONCLUSIONS

Due to the similar symptoms of some parasitic diseases and COVID-19 and immunosuppressive treatment regimens in these patients that may cause the reactivation or recurrence of parasitic infections, early diagnosis and treatment are required.

Subtype Distribution of Blastocystis spp. in Patients with Gastrointestinal Symptoms in Northern Spain

Limited molecular data exist on the prevalence and subtype distribution of Blastocystis spp., the most prevalent parasite in human and animal feces worldwide. A total of 44 different subtypes (STs) of Blastocystis are currently recognized based on the sequence of the small subunit ribosomal RNA (SSU-rRNA) gene. This is a molecular study of Blastocystis spp. in hospitalized patients with gastrointestinal symptoms in northern Spain. We analyzed 173 Blastocystis-positive patients with gastrointestinal symptoms by using nested PCR for molecular detection, subtype identification, phylogenetic analyses, and genetic diversity assessment. ST2 (34.1%) and ST3 (34.7%) predominated, followed by ST1 (15.6%) and ST4 (15.6%). Mixed infections with different subtypes were observed in some patients. Sequence analysis revealed for the first time in European humans the allele 88 (a variant of ST1). In other cases, alleles commonly found in animal samples were detected (allele 9 in ST2, allele 34 in ST3, and allele 42 in ST4). Phylogenetic analysis showed high variability in ST1 and ST2, suggesting a polyphyletic origin, while both ST3 and ST4 exhibited higher genetic homogeneity, indicating a possible monophyletic origin and recent transmission to humans. These data confirm Blastocystis spp. subtype diversity and may help in understanding the evolutionary processes and potential zoonotic transmission of this parasite.

Blastocystis: A Mysterious Member of the Gut Microbiome

Blastocystis is the most common gastrointestinal protist found in humans and animals. Although the clinical significance of Blastocystis remains unclear, the organism is increasingly being viewed as a commensal member of the gut microbiome. However, its impact on the microbiome is still being debated. It is unclear whether Blastocystis promotes a healthy gut and microbiome directly or whether it is more likely to colonize and persist in a healthy gut environment. In healthy people, Blastocystis is frequently associated with increased bacterial diversity and significant differences in the gut microbiome. Based on current knowledge, it is not possible to determine whether differences in the gut microbiome are the cause or result of Blastocystis colonization. Although it is possible that some aspects of this eukaryote's role in the intestinal microbiome remain unknown and that its effects vary, possibly due to subtype and intra-subtype variations and immune modulation, more research is needed to characterize these mechanisms in greater detail. This review covers recent findings on the effects of Blastocystis in the gut microbiome and immune modulation, its impact on the microbiome in autoimmune diseases, whether Blastocystis has a role like bacteria in the gut-brain axis, and its relationship with probiotics.

Prevalence of Blastocystis sp. in Morocco: Comparative assessment of three diagnostic methods and characterization of parasite forms in Jones' culture medium

Blastocystosis is an infection caused by Blastocystis sp., which colonizes the digestive tract of various hosts, including humans, although its pathogenicity is debated. It is crucial to detect and distinguish the different forms of Blastocystis to understand better its impact on human health and its epidemiological evolution. This study evaluated three diagnostic methods on 105 stool samples: direct examination, culture in Jones' medium, and conventional PCR. PCR is considered the gold standard and revealed a high prevalence of Blastocystis (67.62%) compared to direct examination (20.95%) and culture in Jones' medium (51.43%). Although the sensitivity of direct examination and culture was 31% and 76.1%, respectively, their specificity was 100%. No significant risk factors were identified. A statistically significant association was observed between Blastocystis infection and abdominal pain. Microscopic analysis revealed various morphological forms. Molecular diagnosis is an essential tool to determine the true prevalence of Blastocystis, and studying the different forms of this microorganism will contribute to a better understanding of its biological cycle and, therefore, the impact of this emerging infection on human health.

Prevalence of Blastocystis and Dientamoeba fragilis in diarrheal patients in Corum, Türkiye

To investigate the prevalence of Blastocystis and Dientamoeba fragilis in diarrhea patients and healthy individuals in Corum, Türkiye, fecal samples from 92 diarrhea patients and 50 healthy individuals were collected and evaluated using direct microscopy and molecular methods to screen for bacteria, protozoa, and viruses. The prevalence of Blastocystis was 24.6% in total and more frequent in the healthy group (30.0%). The commonly detected STs (subtypes) were ST3 (40.0%) and ST2 (34.2%). The distribution of Blastocystis STs in the healthy and diarrheal groups did not show any difference in sex and age, but ST3 was detected more frequently in patients aged from 40 to 59 years (p < 0.05). Alleles 4 (8/12) and 2 (4/12) were present in ST1; 9 (3/5) and 12 (2/5) in ST2; 34 (9/14), 36 (3/14), and 38 (2/14) in ST3; and only allele 42 (2/2) in ST4. D. fragilis was present in 8.4% of the population. However, there was no statistically significant difference between the healthy and diarrheic groups (12.0% and 6.5%, respectively), neither with respect to age nor sex. Co-infection was 58.3% and was more frequent in healthy individuals (33.3%) than in diarrhea patients (25.0%). Blastocystis ST3 was the most common subtype detected, with D. fragilis at 33.3%. Salmonella, Shigella, or helminth eggs were not observed in all groups, but Entamoeba histolytica, Giardia intestinalis, Cryptosporidium, Rotavirus, Adenovirus, and Clostridium difficile toxin were found only in diarrhea patients. These findings support the hypothesis that Blastocystis and D. fragilis may be part of the healthy human gut microbiome.

Prevalence and genetic diversity of Blastocystis sp. among autochthonous and immigrant patients in Italy

The prevalence of Blastocystis sp., its genetic diversity and the distribution of circulating subtypes (STs) were molecularly investigated in a cohort of autochthonous and immigrant patients with gastrointestinal symptoms hospitalized over the period February 2022-June 2023 at the Policlinico Ospedaliero-Universitario "Riuniti", Foggia, in Southern Italy. The population variables, including patient geographical origin, gender and age classes were reported. Out of the 927 investigated patients, 36 (3.9%) were positive for Blastocystis sp. A statistically significant association with African origin and age classes >18 years old was found. ST1 (allele 4), ST2 (alleles 9, 13), ST3 (alleles 34, 36) and ST4 (allele 92) were the subtypes detected with a different distribution between autochthonous and immigrant patients. Co-infections with enteric protozoa such as Giardia duodenalis and Dientamoeba fragilis, pathogenic bacteria as Clostridioides difficile, Campylobacter jejuni and Aeromonas sp. and viral infections such as Norovirus were found in 33% of cases. This is the first study of Blastocystis sp., its circulating subtypes and allele variability among patients with different geographical origin in an area of Southern Italy, in the Central Mediterranean, characterized by high immigrant pressure. These results provide baseline data to better investigate a potential interaction between Blastocystis sp. and other risk factors in patients with gastrointestinal symptoms.

Effects of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei supplementation on the single-cell fecal parasitome in children with celiac disease autoimmunity: a randomized, double-blind placebo-controlled clinical trial

BACKGROUND

Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 positively affect the fecal bacteriome in children with celiac disease autoimmunity after 6 months of supplementation. The aim of the present investigation was to study the effects of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 on the single-cell parasitome, with a primary focus on Blastocystis.

METHODS

Stool samples were collected from 78 Swedish children with celiac disease autoimmunity participating in a randomized, double-blind, placebo-controlled clinical trial to either receive a mixture of supplementation with L. plantarum HEAL9 and L. paracasei 8700:2 (n = 38) or placebo (n = 40). A total of 227 stool samples collected at baseline and after 3 and 6 months of intervention, respectively, were retrospectively analyzed for Blastocystis by quantitative real-time PCR and subtyped by massively parallel amplicon sequencing. Other single-cell parasites were detected by untargeted 18S rDNA amplicon sequencing and verified by real-time PCR. The relation between the parasites and the bacteriome community was characterized by using 16S rDNA profiling of the V3-V4 region.

RESULTS

Three different single-cell protists were identified, of which the highest prevalence was found for Dientamoeba fragilis (23.1%, 18/78 children), followed by Blastocystis (15.4%, 12/78) and Entamoeba spp. (2.6%, 2/78). The quantity of the protists was stable over time and not affected by probiotic intervention (P = 0.14 for Blastocystis, P = 0.10 for D. fragilis). The positivity of the protists was associated with increased bacteriome diversity (measured by multiple indices, P < 0.03). Bacterial composition was influenced by the presence of the protists: positivity of Blastocystis was inversely associated with Akkermansia (at the levels of the genus as well as its family, order, class and phylum); P < 0.002), Faecalibacterium (P = 0.003) and Romboutsia (P = 0.029); positivity of D. fragilis was inversely associated with families Enterobacteriaceae (P = 0.016) and Coriobacteriaceae (P = 0.022) and genera Flavonifractor (P < 0.001), Faecalibacterium (P = 0.009), Lachnoclostridium (P = 0.029), Ruminococcus (P < 0.001) and Granulicatella (P = 0.018).

CONCLUSIONS

The prevalence of single-cell protists is low in children with celiac disease autoimmunity. The colonization was stable regardless of the probiotic intervention and associated with increased diversity of the fecal bacteriome but inversely associated with some beneficial bacteria.

Impact factors of Blastocystis hominis infection in persons living with human immunodeficiency virus: a large-scale, multi-center observational study from China

BACKGROUND

Blastocystis hominis (Bh) is zoonotic parasitic pathogen with a high prevalent globally, causing opportunistic infections and diarrhea disease. Human immunodeficiency virus (HIV) infection disrupts the immune system by depleting CD4+ T lymphocyte (CD4+ T) cell counts, thereby increasing Bh infection risk among persons living with HIV (PLWH). However, the precise association between Bh infection risk and HIV-related biological markers and treatment processes remains poorly understood. Hence, the purpose of the study was to explore the association between Bh infection risk and CD4+ T cell counts, HIV viral load (VL), and duration of interruption in antiviral therapy among PLWH.

METHODS

A large-scale multi-center cross-sectional study was conducted in China from June 2020 to December 2022. The genetic presence of Bh in fecal samples was detected by real-time fluorescence quantitative polymerase chain reaction, the CD4+ T cell counts in venous blood was measured using flowcytometry, and the HIV VL in serum was quantified using fluorescence-based instruments. Restricted cubic spline (RCS) was applied to assess the non-linear association between Bh infection risk and CD4+ T cell counts, HIV VL, and duration of interruption in highly active antiretroviral therapy (HARRT).

RESULTS

A total of 1245 PLWH were enrolled in the study, the average age of PLWH was 43 years [interquartile range (IQR): 33, 52], with 452 (36.3%) being female, 50.4% (n = 628) had no immunosuppression (CD4+ T cell counts > 500 cells/μl), and 78.1% (n = 972) achieved full virological suppression (HIV VL < 50 copies/ml). Approximately 10.5% (n = 131) of PLWH had interruption. The prevalence of Bh was found to be 4.9% [95% confidence interval (CI): 3.8-6.4%] among PLWH. Significant nonlinear associations were observed between the Bh infection risk and CD4+ T cell counts (Pfor nonlinearity < 0.001, L-shaped), HIV VL (Pfor nonlinearity < 0.001, inverted U-shaped), and duration of interruption in HARRT (Pfor nonlinearity < 0.001, inverted U-shaped).

CONCLUSIONS

The study revealed that VL was a better predictor of Bh infection than CD4+ T cell counts. It is crucial to consider the simultaneous surveillance of HIV VL and CD4+ T cell counts in PLWH in the regions with high level of socioeconomic development. The integrated approach can offer more comprehensive and accurate understanding in the aspects of Bh infection and other opportunistic infections, the efficacy of therapeutic drugs, and the assessment of preventive and control strategies.

Epidemiology of Blastocystis Infection: A Review of Data from Poland in Relation to Other Reports

Blastocystis is a common gut protist of humans and various animals worldwide, with a high level of genetic diversity. Neither its zoonotic potential and transmission routes nor its pathogenicity are fully known. This fact, and the fact that Blastocystis is the most abundant eukaryote in human faeces, raises the question of its relevance to public health. Here, we summarise (in relation to other reports) the results of studies on the prevalence and genotypic variation of Blastocystis, which were carried out in animals, humans, and in water environments in Poland. In humans, the prevalence ranged between 0.14 and 23.6%, in some animals reached 58.97%, and in water environments was 5.1%. Seven subtypes were identified in humans (ST1-ST4, ST6, ST7, and ST9), of which ST3 was the most common. Among animals (wild, livestock, and pet animals), eleven STs were identified, with differential host specificity. Humans and animals shared ST1, ST2, ST3, ST6, and ST7, while ST1 and ST3 were present in humans, animals, and water sources. These observations indicate the possibility of Blastocystis transmission between animals and humans. Further studies should be continued in search of the sources and transmission routes of Blastocystis in order to prevent the spread of infections among humans and animals.

Intestinal Parasitic Infections in 2023

Intestinal parasites include intestinal protozoa and intestinal helminths. Intestinal parasitic infections (IPIs) pose a global health problem affecting over one billion people worldwide. Although these infections are predominantly seen in the developing world, they are frequently seen in the developed countries, particularly in immunocompromised patients. Patients' clinical presentations generally include diarrhea, dysentery, abdominal pain, nausea, vomiting, nutritional deficiency, iron deficiency anemia, anal and perianal itching, and rarely intestinal obstruction. The intestinal parasites have similarities in their mode of transmission and life cycle. The stool test is the primary way of diagnosing IPIs. Treatment is given with various anti-parasitic agents. However, appropriate preventive measures are essential for successfully controlling the IPIs.

Exploring Blastocystis genetic diversity in rural schoolchildren from Colombia using next-generation amplicon sequencing reveals significant associations between contact with animals and infection risk

Blastocystis is a common intestinal protist with a global distribution in humans and many other animals. Yet, the status of Blastocystis as a pathogen, the risk factors associated with its transmission, and its zoonotic potential remain ill-defined. Here, we explored subtype (ST) diversity and potential risk factors for Blastocystis infection in 98 children from Apulo, Colombia. Samples were screened for Blastocystis via PCR, and ST identification was performed through next-generation amplicon sequencing (NGS). Associations between the presence of Blastocystis and individual STs and sociodemographic variables were assessed via logistic regression analyses. Seventy-one samples (72.4%) were Blastocystis-positive, and NGS revealed the presence of five STs (ST1-ST5). ST1, ST2, and ST3 were common and observed in nearly equal proportions (~ 40%), while samples with ST4 (1.4%) and ST5 (5.6%) were comparatively rare. The presence of mixed STs in the same sample was also common (28.2%). Comparisons among children within the same household identified that shared ST profiles were common, but diversity within family units was also observed. Logistic regression analyses returned significant associations between the presence of Blastocystis, individual subtypes, or mixed subtypes for several variables. Intriguingly, the presence of animals was one of the most common significant associations. Taken together, these data represent an important step forward in understanding both the potential routes and risk factors that may influence Blastocystis transmission and will be useful in shaping future studies which seek to clarify the relationships between STs, pathogenicity, and zoonotic transmission.

Investigation of Blastocystis hominis Frequency in Patients with Diabetes by Microscopy and Conventional PCR Methods

Background

We aimed to determine the frequency and subtype of B. hominis in diabetic patients.

Methods

One hundred and fifty diabetic patients and 100 healthy people without any chronic disease were included in the study. Stool samples were analyzed by native-Lugol, condensation, trichrome staining and PCR methods.

Results

İn 150 patients with diabetes; B. hominis was detected in 38 (25.3%) by PCR, in 34 (22.7%) by native-Lugol and trichrome staining. In the control group, 14 (14%) out of 100 subjects were positive by PCR, and 10 (10%) were positive by native-Lugol and trichrome staining. In the statistical evaluation, a significant difference was found between gender (P=0.023), age (P=0.045; ≤35 and >35 comparison), duration of diabetes (P=0.04), the HbA1c value (P=0.023; <8 and ≥8 comparison), and B. hominis positivity. ST1 was determined in 76.9% of patients with diabetes, and ST2 was determined in 23.07%. Considering the 3 methods, B. hominis positivity was detected in 40 patients (26.7%) in diabetic group and in 14 participants (14%) in the control group (P=0.011).

Conclusion

B. hominis is a factor to be considered in patients with diabetes. Herein, the most common subtype detected in the patients with diabetes mellitus was ST1, but this result was not considered sufficient to reveal the importance of the subtype factor in the pathogenicity of B. hominis in patients with diabetes. In this context, there is a need for more comprehensive studies in both diabetic and other immunocompromised patient groups.

Prevalence and temporal dynamics of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. among toddlers attending day-care centres in Spain. A prospective molecular-based longitudinal study

Giardia duodenalis, Cryptosporidium spp., and Blastocystis sp. are common intestinal eukaryotic parasites affecting children in developed and resource-limited countries. Lack of information on the epidemiology and long-term stability in asymptomatic children complicates interpretation of transmission and pathogenesis. To assess the occurrence, genetic diversity, and temporal dynamics of intestinal eukaryotic parasites in young children, 679 stool samples from 125 toddlers attending six public day-care centres in Central Spain were collected bimonthly within a 1-year period. Detection and identification of species/genotypes were based on PCR and Sanger sequencing methods. Four eukaryotic species were identified: G. duodenalis (2.5‒31.6%), Cryptosporidium spp. (0.0‒2.4%), Blastocystis sp. (2.5‒6.4%), and Entamoeba dispar (0.0‒0.9%). Entamoeba histolytica and Enterocytozoon bieneusi were undetected. Sequence analyses identified assemblage A (63.6%) and B (36.4%) within G. duodenalis (n = 11), C. hominis (40%), C. parvum (40%), and C. wrairi (20%) within Cryptosporidium spp. (n = 5), and ST1 (3.8%), ST2 (46.2%), ST3 (15.4%), and ST4 (34.6%) within Blastocystis sp. (n = 26). Giardia duodenalis sub-assemblage AII/AIII was detected in a toddler for 10 consecutive months. Stable carriage of Blastocystis ST2 allele 9, ST3 allele 34, and ST4 allele 42 was demonstrated in five toddlers for up to 1 year.   Conclusions: Giardia duodenalis and Blastocystis sp. were common in toddlers attending day-care centres in Central Spain. Long-term infection/colonization periods by the same genetic variant were observed for G. duodenalis (up to 10 months) and Blastocystis sp. (up to 12 months). What is Known: • Asymptomatic carriage of G. duodenalis and Blastocystis sp. is frequent in toddlers. • The epidemiology and long-term stability of these eukaryotes in asymptomatic young children is poorly understood. What is New: • Long-term colonization/infection periods by the same genetic variant were described for Blastocystis sp. (up to 12 months) and G. duodenalis (up to 10 months).

Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review

There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.

Frequency, subtypes distribution, and risk factors of Blastocystis spp. in COVID-19 patients in Tehran, capital of Iran: A case-control study

Background

Recent theories on the possible interactions between the intestinal parasites and COVID-19 have stated that these co-infections may cause immune imbalance and further complications in the affected patients. Until now, there is no data about Blastocystis subtypes as an intestinal parasite in COVID-19 patients. Therefore, the present work was done to evaluate the molecular prevalence of Blastocystis spp. and related risk factors in Iranian patients with COVID-19.

Method

Stool samples were gathered from 200 COVID-19 patients and 200 control, being matched regarding age, gender and residence. Then, stool samples were surveyed by parasitological methods, including direct slide smear and formalin-ether concentration. In the following, PCR and sequencing were used to detect Blastocystis spp. and their subtypes.

Results

The frequency of Blastocystis spp. in patients with COVID-19 (7.5%; 15/200 by molecular method vs. 6%; 12/200 by microscopy method) was slightly higher than in individuals without COVID-19 (4.5%; 9/200 by molecular method vs. 4%; 8/200 by microscopy method), this difference was not statistically significant (P value = 0.57 for molecular method vs. P value = 0.81 for microscopy method). Regarding associated factors for Blastocystis spp., we found significant differences regarding the residence (rural), loose and watery stool with diarrhea, and duration of treatment (6 weeks <) in the COVID-19 group. Blastocystis ST3 was the most common subtype in the patients with COVID-19 and control group.

Conclusions

Based on this results, health education, improved sanitation and good personal hygiene are highly recommended to prevent Blastocystis in COVID-19 patients.

Prevalence, Subtype Distribution and Zoonotic Significance of Blastocystis sp. Isolates from Poultry, Cattle and Pets in Northern Egypt

Blastocystis sp. is a widespread enteric protozoan that frequently infects human and animal groups. Despite its burden and zoonotic potential worldwide, epidemiological investigations remain limited in animal groups that come in contact with humans. Therefore, the largest survey ever conducted in North Africa was performed in Egypt with the aim to investigate the prevalence and subtype (ST) distribution of Blastocystis sp. in animals. For this purpose, a total of 889 fecal specimens were collected from chickens (217), cattle (373), dogs (144) and cats (155) from six governorates of northern Egypt. These specimens were then screened for the presence of Blastocystis sp. using a quantitative real-time PCR, followed by subtyping the isolates. The overall prevalence of Blastocystis sp. reached 9.2% (82/889), with the highest infection rates reported in chickens (17.0%) and domestic cattle (11.0%), highlighting an active circulation of the parasite in both animal groups. In contrast, the low prevalence in cats (2.6%) and the absence of the parasite in dogs suggested that pets are not natural hosts of Blastocystis sp. ST10 and ST14 were largely predominant in cattle, confirming that both STs represented cattle-adapted STs. The report of one ST3 and one ST4 isolate in this animal group could be explained by an accidental zoonosis from humans to animals. All but one of the subtyped isolates in poultry belonged to ST7, which was considered as an avian ST. The presence of a remaining isolate of ST14 likely reflected a transient infection from contact between birds and cattle feces. The same environmental contamination was also likely the source of the ST14 infection in three of the four positive cats, with the remaining animals infected by ST3 as the result of human-to-animal transmission. These occurrences and subtyping data, combined with those previously collected in the Egyptian population, implies that poultry could play a significant role as reservoir for zoonotic transmission, which would not be the case for cattle and pets.

Molecular subtyping of Blastocystis sp. detected in patients at a large tertiary referral hospital in Lusaka, Zambia

Background

Blastocystis sp. is a common enteric eukaryote of humans whose pathogenicity is still debatable. However, a number of reported Blastocystis colonization associated with enteric disease exist. In Zambia, presence of the pathogen has previously been reported in children. However, the molecular epidemiology of Blastocystis colonization remains unclarified in Zambia.

Methods and results

Archived stool samples submitted for routine parasitological diagnosis at Zambia's largest tertiary referral hospital positive for Blastocystis sp. by microscopic examination were selected for the study. Subtyping of the Blastocystis was done based on polymerase chain reactions (PCR) amplification, sequencing and subsequent phylogenetic analysis of the 18S small subunit (SSU) rDNA gene. Four subtypes, ST1 (allele 4), ST2 (allele 12), ST3 (allele 34, 36, 37, 38, 39) and ST6 (allele 122), were identified by molecular procedures in the study, with some Zambian sequences showing close relationships with those detected in non-human primates and common rats.

Conclusions

The study revealed the circulation of multiple Blastocystis subtypes ST1, 20% (9/45), ST2, 15% (7/45), ST3 24.4% (11/45), and ST6, 2.2% (1/45) in the study population. The close clustering of some Zambian sequences with those detected from animals suggests the possibility of the presence of both anthroponotic and zoonotic transmission cycles in the country. Further studies in animal populations are recommended for a better understanding of the epidemiology of Blastocystis and for implementation of effective evidence-based control strategies.

Higher amoebic and metronidazole resistant forms of Blastocystis sp. seen in schizophrenic patients

Background

Blastocystis sp. is one of the most common colonisers of the intestinal tract that demonstrate strong interaction with accompanying gut bacteria. Previously, the protozoan isolated from individuals with irritable bowel syndrome (IBS) showed altered phenotypic features suggesting that it can be triggered to become pathogenic. Previous studies reported altered gut microbiota and high prevalence of Blastocystis sp. in schizophrenia patients. However, the phenotypic characteristics of Blastocystis sp. isolated from individuals with SZ have yet to be described.

Methods

In this study, faecal samples from 50 patients with severe schizophrenia (SZ) and 100 non-schizophrenic (NS) individuals were screened for Blastocystis sp. infection. Positive isolates were subjected to genotypic and phenotypic characterization.

Results

We found that 12 out of 50 (24%) SZ and 5 out of 100 (5%) NS individuals were detected Blastocystis sp. positive using both in vitro culture and PCR method with no significant association to age and gender. Out of the 15 sequenced isolates, ST3 was the most prevalent subtype (66.7%) followed by ST1 (20%) and ST6 (13.3%). The isolates from SZ individuals demonstrated significant slower growth rate (34.9 ± 15.6 h) and larger range of cell diameter (3.3–140 µm). We detected higher amoebic forms and metronidazole resistance among SZ isolates with variation in cell surface glycoprotein where 98% of cells from SZ showed consistent medium to high binding affinity (+ 2 to + 3) to Concavalin A staining compared to NS isolates that demonstrated only 76% high lectin (+ 3) binding affinity. Cysteine and serine protease levels were predominantly found among SZ isolates. We also demonstrate the presence of metalloprotease in Blastocystis sp. especially among NS isolates. Introduction of solubilised antigens from SZ isolates increased the cell proliferation of HCT116 cells by two fold when compared to NS isolates.

Conclusion

Our findings demonstrated Blastocystis sp. isolated from SZ individuals showed variation in phenotype specifically in morphology and drug resistance. The findings indicate that the gut environment (SZ and NS) and treatment of SZ could have influenced the phenotype of Blastocystis sp.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05418-0.

Prevalence and Associated Factors of Blastocystis sp. Infection in Patients with Gastrointestinal Symptoms in Spain: A Case-Control Study

Blastocystis sp. is known to be the most prevalent parasite in fecal samples of humans worldwide. In the present report, a case-control study (1:9.89 (≈10)) was performed, by analyzing data from 3682 patients who attended a public hospital in the northern area of Spain showing gastrointestinal symptoms. Diagnosis was performed in human fecal samples by means of optical microscopy. The prevalence of Blastocystis sp. in patients with gastrointestinal symptoms was 9.18% (338/3682). Most of the Blastocystis sp.-infected patients tested negative for protozoa and helminths, and were underweight and foreign-born (26.4%), mainly from Africa and Central/South America. Gastrointestinal symptoms, such as abdominal pain, anorexia, halitosis, plus relative eosinophilia, as well as co-infections with pathogenic bacteria were associated with Blastocystis sp. infection. Both type 2 diabetes and treatment with immunosuppressive medicines at the time of Blastocystis sp. detection were associated with a higher proportion of infected patients. This is the first case-control study of Blastocystis sp. in humans in northern Spain and may contribute to surveillance and intervention strategies by public health authorities.

Comparison of molecular diagnostic approaches for the detection and differentiation of the intestinal protist Blastocystis sp. in humans

Blastocystis is the most commonly found intestinal protist in the world. Accurate detection and differentiation of Blastocystis including its subtypes (arguably species) are essential to understand its epidemiology and role in human health. We compared (i) the sensitivity of conventional PCR (cPCR) and qPCR in a set of 288 DNA samples obtained from stool samples of gut-healthy individuals, and (ii) subtype diversity as detected by next-generation sequencing (NGS) versus Sanger sequencing. Real-time PCR resulted in more positive samples than cPCR, revealing high fecal load of Blastocystis based on the quantification curve in most samples. In subtype detection, NGS was largely in agreement with Sanger sequencing but showed higher sensitivity for mixed subtype colonization within one host. This fact together with use of the combination of qPCR and NGS and obtaining information on the fecal protist load will be beneficial for epidemiological and surveillance studies.

Anti-blastocystosis activity of antioxidant coated ZIF-8 combined with mesoporous silicas MCM-41 and KIT-6

The biocompatible hybrid Zeolitic imidazolate framework-8 (ZIF-8)/structured silica nanocomposite can be loaded with antioxidants such as curcumin and resveratrol to offer multiple advantages of drug functionalization and structural stability. blastocystosis, an enteric parasite, has various outcomes and its treatment includes drugs which have side effects and do not result in a full cure. We aimed to design novel biocompatible nanocomposites containing natural antioxidant, resveratrol or curcumin and ZIF-8/mesoporous silica. We also assessed their anti-blastocystosis activities as bioactive novel nanocomposites. The nano-silica (MCM-41 and KIT-6) was synthesized using a hydrothermal technique and made composite with ZIF-8 using an ultrasonic technique. The antioxidants, curcumin and resveratrol, were loaded over ZIF-8/MCM-41 and ZIF-8/KIT-6 using a rotary evaporator technique to form novel nanocomposites with bioactive properties. The formulated nanocomposites were characterized. To test their biological activity, suspension of cultured blastocystosis cysts (subtype 3) were exposed to increasing concentrations of nanocomposites and the minimal lethal concentration of each nanocomposite was calculated. The bioactive nanocomposites (ZIF-8/KIT-6, ZIF-8/KIT-6/Resveratrol and ZIF-8/MCM-41/Curcumin) were formulated. Anti-blastocystosis activity of the tested nanocomposites was both dose and time dependent. ZIF-8/KIT-6/Resveratol showed the maximum percentage of growth inhibition (~ 100%) at a concentration of 500 µg/ml after 5 h of exposure. More than 90% of blastocystosis cysts’ growth was significantly inhibited at all concentrations of ZIF-8/MCM-41/Curcumin, with different times of exposure, while it occurred only at the highest concentration of ZIF-8/KIT-6 (800 µg/ml). Using cheap, simple, reproducible and scalable techniques, we nano-formulated innovative bioactive nanocomposites, by incorporating the bioactive ZIF-8 (Zn²⁺ with imidazole), structured mesosilica and natural antioxidant compounds, curcumin or resveratrol, to generate multifunctional modalities. These eco-friendly, naturally based, safe, economical, biocompatible, and bioavailable nanocomposites are potential nanotherapeutics. The anti-blastocystosis results of these three nanocomposites indicate their potentially promising innovative and safe use as alternative Blastocystosis therapies.

Detection, Molecular Identification and Transmission of the Intestinal Protozoa Blastocystis sp. in Guinea from a Large-Scale Epidemiological Study Conducted in the Conakry Area

Blastocystis sp. is a single-celled parasite estimated to colonize the digestive tract of 1 to 2 billion people worldwide. Although it represents the most frequent intestinal protozoa in human stools, it remains still under-investigated in countries with a high risk of infection due to poor sanitary and hygiene conditions, such as in Africa. Therefore, the present study was carried out to determine the prevalence and subtype (ST) distribution of Blastocystis sp. in the Guinean population. For this purpose, fecal samples were collected from 500 individuals presenting or not digestive disorders in two hospitals of Conakry. Search for the parasite in stools was performed by real-time PCR targeting the small subunit rDNA gene followed by sequencing of the PCR products for subtyping of the isolates. A total of 390 participants (78.0%) was positive for Blastocystis sp. Five STs were identified in the Guinean cohort (ST1, ST2, ST3, ST4 and ST14) with varying frequency, ST3 being predominant. Among them, ST4 was found in only two patients confirming its global rarity in Africa whereas infections by ST14 were likely the result of zoonotic transmission from bovid. No significant association was detected between Blastocystis sp. colonization or ST distribution and the symptomatic status of Guinean subjects or the presence of digestive symptoms. In contrast, drilling water consumption represented a significant risk factor for infection by Blastocystis sp. Predominance of ST3 coupled with its low intra-ST diversity strongly suggested large-scale human-to-human transmission of this ST within this cohort. In parallel, the highest intra-ST diversity of ST1 and ST2 was likely correlated with various potential sources of infection in addition to anthroponotic transmission. These findings highlighted the active circulation of the parasite in Guinea as reported in some low-income African countries and the necessity to implement prevention and control measures in order to limit the circulation of this parasite in this endemic geographical area.

Prevalence, subtypes and risk factors of Blastocystis spp. infection among pre- and perimenopausal women

Background

Blastocystis spp. are considered pathogenic or commensal organisms, although the majority of researchers suggest that these are neglected pathogens. The main aim of this study was to determine the prevalence and subtype distribution of Blastocystis spp. in pre- and perimenopausal women, with respect to socio-demographic (age and place of residence), and epidemiological factors, as well as drinking tap water, contact with domestic animals, traveling abroad, health status, and presence of gastrointestinal symptoms. Additionally, the objective was to compare hematological and biochemical parameters of Blastocystis spp. infected and uninfected women.

Methods

The study included 425 women aged 45–60. Their stool samples were examined microscopically and analyzed by a conventional polymerase chain reaction (cPCR).

Results

Blastocystis spp. were detected in 6.1% of pre- and perimenopausal women. Molecular analysis of the stool samples identified seven Blastocystis subtypes (ST1–ST4, ST6, ST7, and ST9). Blastocystis subtypes 2 and 3 were the most prevalent. The presence of Blastocystis spp. was not significantly related to socio-demographic and epidemiological factors. There were also no significant associations between Blastocystis spp. and blood parameters, or gastrointestinal symptoms.

Conclusion

This study complements the limited available data on the prevalence of Blastocystis spp. in pre- and perimenopausal women. It is also the first report showing the presence of Blastocystis subtype 9 in Poland.

Zoonotic Transmission of Blastocystis Subtype 1 among People in Eastern Communities of Thailand: Organic Fertilizer from Pig Feces as a Potential Source

Blastocystis sp., the most common intestinal protozoa, remains a public health problem among people in many countries, particularly in rural areas of developing countries. The infection usually reflects poor sanitation in communities by waterborne, zoonotic, and person-to-person transmission. Interestingly, at least 17 subtypes (STs) have been reported and are associated with a broad range of animal hosts, including humans. In this study, we reported potential evidence of zoonotic transmission of Blastocystis ST1 in rural communities of eastern Thailand where the overall prevalence of Blastocystis infection was 15.7%. Two major and three minor subtypes were found to be distributed unequally in this region. Of 5 STs, only ST1 was found to be associated with pig feces in an open farm system that produced organic fertilizer for agriculture uses in the community. This finding suggests that properly protective contact and standard production of organic fertilizer from pig feces by-products could be key factors for reducing the prevalence of Blastocystis infection and prevent Blastocystis reinfection among people in the community.

IMPORTANCEBlastocystis sp. remains a public health problem among people, particularly in rural areas of many developing countries. The infection usually reflects poor sanitation in communities by waterborne, zoonotic, and person-to-person transmission. In this study, we reported potential evidence of zoonotic transmission of Blastocystis subtype 1 (ST1) in rural communities of eastern Thailand. Two major and three minor subtypes were found to be unequally distributed in this region. Interestingly, only ST1 was found to be associated with pig feces in an open farm system that produced organic fertilizer for agriculture uses in the community. The finding makes significant contributions to genetic and molecular investigations of microbial topics of practical value and suggest that properly protective contact and standard production of organic fertilizer from pig feces by-products could be key factors for reducing the prevalence of Blastocystis infection and prevent Blastocystis reinfection among people in the community.

Investigation of neglected protists Blastocystis sp. and Dientamoeba fragilis in immunocompetent and immunodeficient diarrheal patients using both conventional and molecular methods

Introduction

The clinical significance of Blastocystis sp. and Dientamoeba fragilis in patients with gastrointestinal symptoms is a controversial issue. Since the pathogenicity of these protists has not been fully elucidated, testing for these organisms is not routinely pursued by most laboratories and clinicians. Thus, the prevalence of these organisms and the subtypes of Blastocystis sp. in human patients in Turkey are not well characterized. This study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in the diarrheic stool samples of immunodeficient and immunocompetent patients using conventional and molecular methods and to identify Blastocystis sp. subtypes using next generation sequencing.

Material and methods

Individual stool specimens were collected from 245 immunodeficient and 193 immunocompetent diarrheic patients between March 2017 and December 2019 at the Gazi University Training and Research Hospital in Ankara, Turkey. Samples were screened for Blastocystis sp. and D. fragilis by conventional and molecular methods. Molecular detection of both protists was achieved by separate qPCRs targeting a partial fragment of the SSU rRNA gene. Next generation sequencing was used to identify Blastocystis sp. subtypes.

Results

The prevalence of Blastocystis sp. and D. fragilis was 16.7% and 11.9%, respectively as measured by qPCR. The prevalence of Blastocystis sp. and D. fragilis was lower in immunodeficient patients (12.7% and 10.6%, respectively) compared to immunocompetent patients (21.8% and 13.5%, respectively). Five Blastocystis sp. subtypes were identified and the following subtype distribution was observed: ST3 54.4% (n = 37), ST2 16.2% (n = 11), ST1 4.4% (n = 3), ST6 2.9% (n = 2), ST4 1.5% (n = 1), ST2/ST3 11.8% (n = 8) and ST1/ST3 8.8% (n = 6). There was no statistically significant difference in the distribution of Blastocystis sp. subtypes between immunocompetent and immunodeficient patients.

Conclusion and recommendation

Our findings demonstrated that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea. This study is the first to use next generation sequencing to address the presence of Blastocystis sp. mixed subtypes and intra-subtype variability in clinical samples in Turkey.

Blastocystis sp. and Dientamoeba fragilis are single-cell parasites of the human intestine which are common worldwide and reported in cases with gastrointestinal symptoms. However, the role of Blastocystis sp. and D. fragilis in patients with gastrointestinal symptoms is still controversial because their presence is not always associated with symptoms. As some intestinal parasitic infections can cause severe illness in immunocompromised individuals careful consideration of intestinal protist infection is warranted. However, testing for Blastocystis sp. and D. fragilis is not routinely carried out by most laboratories and clinicians. Therefore, this study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in immunocompetent and immunosuppressed patients with diarrhea by conventional and molecular methods. Both Blastocystis sp. and D. fragilis were detected more frequently by quantitative polymerase chain reaction than by conventional methods. Next generation sequencing was used to characterize the diversity and frequency of Blastocystis sp. subtypes and mixed subtypes in patients in Turkey. Five Blastocystis sp. subtypes (ST1, ST2, ST3, ST4 and ST6) were detected. ST3 was the most frequent subtype in both immunocompetent and immunosuppressed patients. Mono-infections were more common than mixed subtype infections. Our findings showed that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea.

Prokaryotic and Eukaryotic Fecal Microbiota in Irritable Bowel Syndrome Patients and Healthy Individuals Colonized With Blastocystis

Blastocystis is the most frequently isolated protozoan from human stool. Its role in human health is still debated, and a high prevalence was reported in irritable bowel syndrome (IBS) subjects, suggesting a potential link with microbiota. In the present study, we aimed to investigate prokaryotic and eukaryotic microbiota in both IBS-C (constipated) and healthy individuals. We recruited 35 IBS-C patients and 23 healthy subjects, from which 12 and 11 carried Blastocystis, respectively. We performed 16S and 18S rRNA high-throughput sequencing on feces. Whereas we did not observe differences between infected and non-infected controls, several phyla were significantly modified in IBS-C patients according to the presence of Blastocystis. Tenericutes phylum and Ruminococcaceae family were especially increased in Blastocystis carriers. Furthermore, colonization with Blastocystis was associated with discrete changes in the microbial eukaryome, particularly among the Fungi taxa. Depending on the group of patients considered, the mycobiota changes do not go in the same direction and seem more deleterious in the IBS-C group. These results encourage further in vivo and in vitro investigations concerning the role of Blastocystis in the gut environment.

Molecular prevalence and subtype distribution of Blastocystis sp. in Asia and in Australia

Blastocystis is a prevalent protozoan parasite reported in humans, animals, and environmental samples. Over the past decade, numerous studies have investigated the prevalence and subtype distribution of Blastocystis sp. alongside with its genetic and biochemical features. However, studies on subtype distribution of this protozoan in humans, animals, and environmental samples represent the potential transmission routes. In this review, we evaluated studies performed in Asian countries and in Australia to provide an overview of environmental factors on the prevalence and subtype distribution of Blastocystis sp. among humans, animals, and the environment.

Epidemiology and subtype distribution of Blastocystis in humans: A review

Blastocystis is a commonly encountered gastrointestinal protozoan in humans and animals with uncertain pathogenicity. Despite its potential public health impact, epidemiological data regarding the prevalence and molecular subtype (ST) distribution of Blastocystis have been rarely reported. Among Blastocystis STs, ST1-ST4 are common in humans, including healthy and immunodeficient populations. According to the Chi-squared (χ²) association based on the data compiled for this cross-sectional study, the presence of ST1 is associated with asymptomatic infection, whereas the presence of ST4 is associated with symptomatic infection. However, cross-sectional studies cannot clarify the potential pathogenicity of Blastocystis, unlike in vivo and in vitro studies. Poor hygiene, poor sanitation and zoonotic transmission are possible factors associated with high Blastocystis prevalence, although this protozoan may be part of the normal healthy human gastrointestinal microbiota. This review covers the prevalence, STs and distribution of Blastocystis infection in humans. Thus, future epidemiological and subtyping studies could reveal new STs in humans as well as possible associations of STs with disease, drug resistance and related mechanisms such as protease activity. These associations with proper ST identification may facilitate the control of potential threats to host health, including the direct pathogenic effects of Blastocystis or alterations of the gastrointestinal microbiome.

Prevalence of Intestinal Parasitic Infections among Children in Europe over the Last Five Years

While the prevalence of intestinal parasitic infections (IPI) has been most commonly studied in African and Asian populations, less is known about the prevalence rates of IPI in European children, as well as the potential risk factors that favor the spread of parasites. We aimed to review published evidence on the prevalence rates of IPI in children residing in Europe, and to quantitatively synthesize the results of published studies. We searched Medline from 1 January 2015 to 1 April 2021 to address the most recently published prevalence patterns of IPI in European children. Random-effects meta-analyses were performed by type of IPI infection, age group and sex, depending on data availability. Of the 967 potentially relevant articles, eight eligible cross-sectional studies were included in this analysis, yielding a sample of 3376 children (0-19 years). The overall prevalence rate was 5.9% for any IPI in children residing in European countries. Blastocystis hominis was the most commonly detected parasite yielding a prevalence rate of 10.7%. Other parasites included Entamoeba coli, Endolimax nana, and Blastocystis hominis. Studies focusing on specific types of parasites showed prevalence rates ranging from 1.3% for Cryptosporidium to 68.3% for Dientamoeba fragilis. Despite the scarce literature, the present review showed relatively low prevalence rates of IPI in Europe. Future studies accounting for proper diagnostic methods used for the detection of parasites and including information on potential sociodemographic factors, such as travelling history and history of immigration, are needed to guide clinicians about which children to test, as well as when and how to test children for IPI.

Genotypes of Blastocystis sp. among elderly health checkup people in South Korea with a questionnaire on risk factors

Blastocystis sp. is a common zoonotic intestinal parasite of humans and animals, and has been classified into at least 17 distinct subtypes. Despite its potential impact on public health, the prevalence and subtype distribution of Blastocystis sp. have seldom been the study subject in South Korea. To determine the prevalence and subtype distribution of Blastocystis sp. and to obtain information on risk factors, we performed a cross-sectional study targeting elderly health checkup people, who visited Seoul Western Branch of the Korea Association of Health Promotion (KAHP) in October 2019. Stool samples were collected from 293 participants consisting of 128 males and 165 females with a mean age of 64.7 years (from 50 to 88 years) with a questionnaire on potential risk factors. All the samples were tested by PCR targeting the SSU rRNA gene of Blastocystis sp., and nucleotide sequences of positive samples were used to identify the subtypes. The overall prevalence of Blastocystis sp. was 9.2% (27/293). Among the positive samples, subtype 3 was predominant (59%; 16/27), followed by subtype 1 (41%; 11/27). No other subtypes were detected. In the univariable analysis, the age, sex, presence of digestive symptoms, source of drinking water, and history of drug intake were not significantly associated with Blastocystis sp. infection. Two parameters, including the Enterococcus hirae bacterial infection and the frequency of intake of cooked or boiled vegetables less than twice a week, showed statistical significance. However, the multivariable regression analysis revealed that only the latter parameter was statistically significant. The results suggested that subtypes 3 and 1 are the 2 major genotypes of Blastocystis sp. among elderly people in South Korea, and low frequency of consuming cooked or boiled vegetables is a potential risk factor.

Blastocystis spp. infection in cases of diarrhea: A pilot study from a tertiary care teaching hospital in Rishikesh, Uttarakhand, with a brief review of literature

CONTEXT

Intestinal parasitic infections (IPI) are among the most common infections throughout the world. Blastocystis spp. is a mysterious parasite which is commonly encountered in tropical countries. Its pathogenic status is unknown and there is a paucity of literature about this organism from the state of Uttarakhand, India.

AIMS

The aim was to estimate the prevalence of Blastocystis spp. in diarrheal stools.

SETTINGS AND DESIGN

This was a cross-sectional study conducted from January 2018 to July 2019.

SUBJECTS AND METHODS

Nonrepetitive stool samples of 187 consecutive patients of diarrhea attending the inpatient department and outpatient department of a tertiary care teaching hospital located in Rishikesh, Uttarakhand, were collected after obtaining informed written consent. These samples were subjected to wet mount microscopy and permanent staining.

STATISTICAL ANALYSIS USED

Fisher's exact test and Kappa coefficient were used in this study.

RESULTS

The mean age ± standard deviation of the patients was 36.04 ± 11.31 years with a male-to-female ratio of 1.49:1. The prevalence of IPI was 36.09%. Giardia intestinalis was the most common parasite. Blastocystis spp. was observed in 6.42% of the stool samples, majority of which were obtained from cases of chronic diarrhea. Moderate agreement (0.48) was observed between wet mount microscopy and permanent staining in the identification of Blastocystis spp.

CONCLUSIONS

This is the first study to assess the burden and role of different epidemiological and clinical profiles of Blastocystis spp. in Uttarakhand. More studies are required to know its pathogenesis and its role as opportunistic pathogen.

Wide Genetic Diversity of Blastocystis in White-Tailed Deer (Odocoileus virginianus) from Maryland, USA

Blastocystis is a gastrointestinal protist frequently reported in humans and animals worldwide. Wildlife populations, including deer, may serve as reservoirs of parasitic diseases for both humans and domestic animals, either through direct contact or through contamination of food or water resources. However, no studies of the occurrence and subtype distribution of Blastocystis in wildlife populations have been conducted in the United States. PCR and next generation amplicon sequencing were used to determine the occurrence and subtypes of Blastocystis in white-tailed deer (Odocoileus virginianus). Blastocystis was common, with 88.8% (71/80) of samples found to be positive. Twelve subtypes were identified, ten previously reported (ST1, ST3, ST4, ST10, ST14, ST21, and ST23–ST26) and two novel subtypes (ST30 and ST31). To confirm the validity of ST30 and ST31, MinION sequencing was used to obtain full-length SSU rRNA gene sequences, and phylogenetic and pairwise distance analyses were performed. ST10, ST14, and ST24 were the most commonly observed subtypes. Potentially zoonotic subtypes ST1, ST3, or ST4 were present in 8.5% of Blastocystis-positives. Mixed subtype infections were common (90.1% of Blastocystis-positives). This study is the first to subtype Blastocystis in white-tailed deer. White-tailed deer were found to be commonly infected/colonized with a wide diversity of subtypes, including two novel subtypes, zoonotic subtypes, and subtypes frequently reported in domestic animals. More studies in wildlife are needed to better understand their role in the transmission of Blastocystis.

Blastocystis species and Gastrointestinal Symptoms in Peruvian Adults Attended in a Public Hospital

The objective of this study was to evaluate the role of Blastocystis sp. in gastrointestinal symptoms reported by adult patients in a Peruvian hospital. A case-control 3:1 study was performed at the outpatient clinic. Direct stool examinations were done. One hundred sixty patients were included, 40 cases and 120 controls. Positivity to Blastocystis sp. was associated with dyspepsia (P <0.001), bloating (P <0.001) and abdominal pain (P = 0.03) in patients attending our hospital outpatient clinic.

Investigation of Isolated Blastocystis Subtypes from Cancer Patients in Turkey

PURPOSE

It is not clear that Blastocystis remains without damage to the digestive tract or has a pathogenic effect in relation to subtypes in immunocompromised people, such as cancer patients. The present study aimed to investigate the frequency and subtype distribution of Blastocystis in cancer patients who were followed-up and treated in the Oncology clinic of Firat University Hospital and to determine the clinical signs of infected sufferers.

METHODS

201 patients aged ≥ 18 with a diagnosis of cancer were enrolled in this cross-sectional study. Patients' stool samples were examined between September 2017 and August 2019 by native-Lugol, trichrome staining. Microscopy-positive stool samples were subjected to DNA isolation and subtyped by Sequence Tagged Site (STS)-PCR analysis. The symptoms and demographic characteristics of the patients were also evaluated.

RESULTS

Totally, 29 (14.4%) samples were positive for Blastocystis after all methods. 15 (51.7%) out of 29 samples were successfully subtyped by the sequenced-tagged site(STS)-PCR, while 14 (48.3%) could not be typed. Three subtypes of Blastocystis were detected: ST3 (40%), ST2 (33%), ST1 (20%), and one mixed infections with ST1/ST2 (6%). There was no statistically significant difference in terms of clinical findings and demographic characteristics.

CONCLUSION

The outcomes of our study promote the idea that Blastocystis could be an asymptomatic and harmless commensal organism. However, more comprehensive molecular and clinical studies are needed to fully determine the pathogenicity and epidemiology of Blastocystis in cancer patients.

Blastocystis sp. Carriage and Irritable Bowel Syndrome: Is the Association Already Established?

Simple Summary

The intestinal protist Blastocystis sp. is one of the most common intestinal parasites observed in humans, and has a worldwide distribution, being more prevalent in developing countries. Although this parasite has been described decades ago, the pathogenic potential it is still not understood completely. It has been suggested that Blastocystis sp. could be related with irritable bowel syndrome, a functional gastrointestinal disorder characterized by abdominal pain, discomfort with defecation, and changes in the frequency or form of stool. In our study, we compare a group of patients with irritable bowel syndrome with a group of healthy volunteers; no differences regarding the occurrence of Blastocystis sp. detection was found between both groups.

Abstract

Background: The aim of the present study is to describe the occurrence of Blastocystis sp. detection among asymptomatic subjects and patients with irritable bowel syndrome in order to evaluate the potential association between irritable bowel syndrome and the parasitic infection. Methods: Cross-sectional study where adult patients with irritable bowel syndrome diagnosed according to Rome IV criteria were included. A control group was formed by asymptomatic subjects older than 18 years. Exclusion criteria were: immunosuppressive condition or having received any drug with demonstrated activity against Blastocystis sp. within the last 6 months before study inclusion. Epidemiological and clinical information was collected from all included participants. Two stool samples were obtained from all participants: one sample for microscopic examination and one sample for Blastocystis sp. PCR detection. Blastocystis sp. infection was defined by the positivity of any of the diagnostic techniques. Results: Seventy-two participants were included (36 asymptomatic subjects and 36 patients with irritable bowel syndrome). Thirty-five (48.6%) were men, and median age of participants was 34 (IQR 29–49) years. The overall rate of Blastocystis sp. carriage was 27.8% (20/72). The prevalence assessed through microscopic examination was 22.2% (16/72), while the prevalence measured by PCR was 15.3% (11/72). When comparing the presence of Blastocystis sp. between asymptomatic subjects and IBS patients, we did not find any statistically significant difference (36.1% vs. 19.4% respectively, p = 0.114). Conclusions: regarding the occurrence of Blastocystis sp., no differences were found between asymptomatic participants and patients with irritable bowel disease irrespective of the diagnostic technique performed.

Colorectal cancer and Blastocystis sp. infection

BACKGROUND

Blastocystis sp. is a common intestinal protozoan found worldwide. Based on gene analysis, 17 subtypes (STs, ST1-ST17) have been identified, 9 of which have been isolated from humans. Differences in clinical consequences may depend on differences among the STs. Here, we evaluated the prevalence of Blastocystis sp. in patients with colorectal cancer (CRC) compared to a control group and assessed the relationships between Blastocystis sp. infection and sex; age; and CRC grade, stage, and location.

METHODS

The study included 107 CRC patients (41 women and 66 men, median age 65 years); 124 subjects without colorectal cancer or a history of oncological disease comprised the control group (55 women and 69 men, median age 63). Stool samples were collected from patients before oncological treatment and examined using light microscopy (iodine-stained smear). Additionally, PCR-based identification of Blastocystis sp. was performed in 95 stool samples from CRC patients and 76 stool samples from the control group.

RESULTS

Light microscopy showed that the prevalence of Blastocystis sp. was significantly higher in CRC patients than in the control group (12.15% and 2.42%, respectively; p = 0.0041). Multivariate analysis showed that the odds of Blastocystis sp. infection were fivefold higher in the CRC group than in the control group. PCR-based molecular examinations demonstrated that the proportion of patients infected with Blastocystis sp. was significantly higher in the CRC group than in the control group (12.63% and 2.63%, respectively; p = 0.023). The predominant ST in the CRC group was ST3, detected in nine patients (75%), followed by ST1 (2 patients, 16.7%) and ST2 (1 patient, 8.3%). No association was found between Blastocystis sp. infection and age, sex, or CRC stage, grade, or location.

CONCLUSIONS

The results showed that CRC was associated with an increased risk of opportunistic Blastocystis sp. infection, even before oncological treatment. To the best of our knowledge, this is the first report estimating the prevalence of Blastocystis sp. infection in CRC patients before oncological treatment in Europe.

In vitro susceptibility of human Blastocystis subtypes to simeprevir

Introduction and aim

Blastocystis is a common enteric parasite, having a worldwide distribution. Many antimicrobial agents are effective against it, yet side effects and drug resistance have been reported. Thus, ongoing trials are being conducted for exploring anti-Blastocystis alternatives. Proteases are attractive anti-protozoal drug targets, having documented roles in Blastocystis. Serine proteases are present in both hepatitis C virus and Blastocystis. Since drug repositioning is quite trendy, the in vitro efficacy of simeprevir (SMV), an anti-hepatitis serine protease inhibitor, against Blastocystis was investigated in the current study.

Methods

Stool samples were collected from patients, Alexandria, Egypt. Concentrated stools were screened using direct smears, trichrome, and modified Ziehl-Neelsen stains to exclude parasitic co-infections. Positive stool isolates were cultivated, molecularly subtyped for assessing the efficacy of three SMV doses (100,150, and 200 μg/ml) along 72 hours (h), on the most common subtype, through monitoring parasite growth, viability, re-culture, and also via ultrastructure verification. The most efficient dose and duration were later tested on other subtypes.

Results

Results revealed that Blastocystis was detected in 54.17% of examined samples. Molecularly, ST3 predominated (62%), followed by ST1 (8.6%) and ST2 (3.4%). Ascending concentrations of SMV progressively inhibited growth, viability, and re-culture of treated Blastocystis, with a non-statistically significant difference when compared to the therapeutic control metronidazole (MTZ). The most efficient dose and duration against ST3 was 150 µg/ml for 72 h. This dose inhibited the growth of ST3, ST1, and ST2 with percentages of 95.19%, 94.83%, and 94.74%, successively and viability with percentages of 98.30%, 98.09%, and 97.96%, successively. This dose abolished Blastocystis upon re-culturing. Ultra-structurally, SMV induced rupture of Blastocystis cell membrane leading to necrotic death, versus the reported apoptotic death caused by MTZ. In conclusion, 150 µg/ml SMV for 72 h proved its efficacy against ST1, ST2, and ST3 Blastocystis, thus sparing the need for pre-treatment molecular subtyping in developing countries.

Blastocystis sp. Prevalence and Subtypes Distribution amongst Syrian Refugee Communities Living in North Lebanon

Molecular data concerning the prevalence and subtype (ST) distribution of the intestinal parasite Blastocystis sp. remain scarce in the Middle East. Accordingly, we performed the first molecular epidemiological survey ever conducted in the Syrian population. A total of 306 stool samples were collected from Syrian refugees living in 26 informal tented settlements (ITS) subjected or not to water, sanitation, and hygiene (WASH) interventions in North Lebanon, then screened for the presence of Blastocystis sp. by real-time polymerase chain reaction followed by subtyping. The overall prevalence of the parasite was shown to reach 63.7%. Blastocystis sp. colonization was not significantly associated with gender, age, symptomatic status, abdominal pain or diarrhea. In contrast, WASH intervention status of ITS was identified as a risk factor for infection. Among a total of 164 subtyped isolates, ST3 was predominant, followed by ST1, ST2, and ST10. No particular ST was reported to be associated with age, gender, symptomatic status, digestive disorders, or WASH intervention status of ITS. Intra-ST diversity of ST1 to ST3 was low suggesting large-scale anthroponotic transmission. Moreover, comparative analysis of ST1 to ST3 genotypes revealed that the circulation of the parasite between Syrian refugees and the host population was likely limited.