Identification and Genetic Characterization of Blastocystis Species in Patients from Makkah, Saudi Arabia

Genetic diversity and prevalence of Blastocystis subtypes in Alborz Province, Iran: A molecular epidemiological study

The primary objective of this study was to evaluate the genetic diversity of Blastocystis. Additionally, it aimed to explore, for the first time in Iran, the potential association between Blastocystis infection and ABO blood groups. Another focus was to examine the relationship between Blastocystis subtypes and blood groups, an often overlooked risk factor, within the population of Alborz Province, Iran. 450 stool samples were collected from diagnostic facilities across Alborz Province between June 2022 and April 2024. The presence of Blastocystis was confirmed in 64 out of 450 samples (14.22 %) using the Nested PCR-RFLP technique. Among the 64 positive samples, nine (2 %) were classified as indeterminate. Two distinct Blastocystis subtypes were identified in 55 isolates, accounting for 12.22 % of the total samples. ST1 was detected in 44 isolates (9.77 %), rendering it the most prevalent subtype, while ST3 was identified in 11 isolates (2.44 %). Phylogenetic trees were constructed using sequencing data and compared against genotypes available in GenBank. Significant differences between infected and non-infected individuals were observed regarding educational attainment, marital status, and blood type (p < 0.05). A significant association was found between ABO blood groups and the prevalence of Blastocystis infection (p = 0.019). However, when examining the correlation between Blastocystis subtypes (ST1 and ST3) and ABO blood groups, no significant overall association was observed. Nonetheless, specific associations were found for blood groups O+ and B-, with subtype ST1 being more prevalent in these groups.

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

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

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.

Molecular Prevalence and Subtypes Distribution of Blastocystis spp. in Humans of Latin America: A Systematic Review

Blastocystis spp. are among the few enteric parasites with a prevalence that can reach up to approximately 80% in communities of developing countries. This systematic review updates and summarizes available literature on the molecular prevalence and subtype distribution of Blastocystis spp. in Latin American people. This work follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The literature revised covers from 1 January 2015 to 6 October 2023 in seven different scientific databases, and the material was selected through inclusion and exclusion criteria. According to data found in the 36 selected articles, the prevalence of Blastocystis spp. in Latin America ranged between 5.8% (Bolivian rural communities) and 94.0% (Colombian general public). Generally, genomic DNA was extracted from approximately 200 mg fecal sediments using commercial kits, such as the QIAamp Stool Mini Kit (QIAGEN, Hilden, Germany) or the Norgen Stool DNA Isolation Kit (Norgen Biotek Corporation, Thorold, ON, Canada). Subtype-specific primers (such as the couple of primers BhRDr-RD5) developed from unique sequences of the SSU rRNA gene were applied to Blastocystis subtyping. Ten specific subtypes (STs) were found as well as various mixed infections, and the most circulating Blastocystis STs were in the order ST3, ST1, ST2, and ST4. The most recent data about Blastocystis spp. molecular epidemiology and the STs in communities of Latin America are limited to studies from specific countries. Novel scientific data from the other countries are required to obtain a complete picture and truly understand the distribution and prevalence of Blastocystis spp. and the STs.

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.

Systematic Review and Meta-Analysis: Epidemiology of Human Blastocystis spp. Infection in Malaysia

Blastocystis spp. is a unicellular enteric protozoan parasite in humans with a controversial role in disease etiology. It is common in developing countries among immunocompromised patients and people who have close contact with animals. In this study, we have systematically reviewed previous studies on the distribution and genotypes of human Blastocystis infection in Peninsular Malaysia. Studies examining the prevalence of Blastocystis in diverse demographics, including rural, urban, comorbid conditions, and high-risk populations, were taken into consideration. The infection has been reported in nine states; the total percentage of infection was 17.8% (1671/9397), with the most cases in Pahang (27.3%) and the least in Johor (3.4%). Molecular studies revealed the presence of six subtypes: ST1, ST2, ST3, ST4, ST5, and ST6. ST3 was reported as the predominant subtype in all the states, with a prevalence of 54.7% (338/618). The findings provide greater clarity on the epidemiology of Blastocystis in Malaysia, which will help in policy making towards planning and strategizing control measures against the parasite.

Colonization with ubiquitous protist Blastocystis ST1 ameliorates DSS-induced colitis and promotes beneficial microbiota and immune outcomes

Blastocystis is a species complex that exhibits extensive genetic diversity, evidenced by its classification into several genetically distinct subtypes (ST). Although several studies have shown the relationships between a specific subtype and gut microbiota, there is no study to show the effect of the ubiquitous Blastocystis ST1 on the gut microbiota and host health. Here, we show that Blastocystis ST1 colonization increased the proportion of beneficial bacteria Alloprevotella and Akkermansia, and induced Th2 and Treg cell responses in normal healthy mice. ST1-colonized mice showed decreases in the severity of DSS-induced colitis when compared to non-colonized mice. Furthermore, mice transplanted with ST1-altered gut microbiota were refractory to dextran sulfate sodium (DSS)-induced colitis via induction of Treg cells and elevated short-chain fat acid (SCFA) production. Our results suggest that colonization with Blastocystis ST1, one of the most common subtypes in humans, exerts beneficial effects on host health through modulating the gut microbiota and adaptive immune responses.

Prevalence of Blastocystis sp. among cooks in the region of Fez-Meknes (Morocco)

Cooks have an important role in the dissemination and transmission of enteropathogenic microorganisms, including intestinal parasites such as Blastocystis sp. responsible for blastocystosis. Blastocystis is a unicellular, anaerobic, eukaryotic protist that colonizes the intestinal tract of many hosts. It is the most common parasite found in human stool. It can be the cause of acute digestive disorders which could lead to chronic syndromes such as irritable bowel syndrome. The aim of the present study is to determine the prevalence of this protozoan in cooks in the Fez-Meknes region. This is a retrospective descriptive analytical study carried out in the Parasitology-Mycology laboratory of the Moulay Ismail Military Hospital in Meknes. Out of a total of 200 parasitological examinations of cooks' stools, 88 (44 %) cases were positive for intestinal parasites. Blastocystis sp. is the most frequently encountered protozoan in our study. It represents 39.78 % of those infected. It is associated in 48.57 % of cases with another intestinal parasite. Dientamoeba fragilis (D. fragilis) is the most found in 31.43 % of co-infections, respectively followed by Entamoeba coli (E. coli) (8.57 %), Endolimax nana (E. nana) (5.71 %) and Pseudolimax boutschlii (P. boutschlii) (2.86 %). Our results showed a high prevalence of Blastocystis sp. in the kitchen staff population. These workers must be considered as reservoirs of this microorganism, and therefore a source of infection in those around them. Consequently, preventive measures are necessary, including raising awareness among this population in order to effectively fight against the infestation by this protozoan in particular and other parasites in general.

Molecular characterization of Blastocystis subtypes in symptomatic patients from the southern region of Syria

Blastocystis sp. is an enteric protist found in humans and a wide range of animal hosts. Genetic variations were established among the 38 different subtypes detected so far, 14 of which are commonly found in human and animal hosts. The aim of the present study is to estimate the prevalence of the common Blastocystis subtypes and evaluate the possible correlation with several variables (gender, age, symptoms, domestic animals…), among patients from the southern region of Syria. Fecal samples were collected from individuals suffering from gastrointestinal complaints. Microscopic examination along with genotype analyses using seven pairs of subtype-specific primers was performed. Our results revealed the presence of Blastocystis sp. in 46 isolates out of the 60 samples microscopically studied (76.7%); single infection was detected in 24 isolates whereas co-infection with other protozoa was identified in 22 ones. Molecular detection targeting the SSU rRNA gene revealed a 100% positive presence of Blastocystis sp. in all the samples. Genotyping results detected the presence of five different subtypes (ST1-ST5) with varying proportions. However, ST1 was the dominant subtype observed (66.7%). Mixed subtype infections were found in 9 isolates (15%). Three samples remained undefined, nonetheless. Our statistical results showed no significant correlation between Blastocystis STs infection and the different studied variables. In conclusion, this study provides the first genetic characterization of Blastocystis subtypes prevalence in patients from the southern region of Syria. ST1 distribution was highly predominant. Further molecular studies are needed to estimate the prevalence of Blastocystis sp. infection in other regions in Syria and to understand the epidemiology and sources of transmission to humans.