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Parasites & Vectors May 2021Blastocystis is a common anaerobic colonic protist in humans with controversial pathogenicity. Clostridium difficile (C. difficile) is the commonest cause of infectious...
BACKGROUND
Blastocystis is a common anaerobic colonic protist in humans with controversial pathogenicity. Clostridium difficile (C. difficile) is the commonest cause of infectious diarrhea in healthcare settings. The prevalence and subtype (ST) characteristics of Blastocystis in patients with C. difficile infection (CDI) are rarely documented. Therefore, the present study was conducted to investigate the prevalence and subtype characteristics of Blastocystis in patients with suspicion of CDI in Singapore.
METHODS
Fecal samples were collected from 248 patients presenting with suspected CDI from a single tertiary hospital in Singapore. C. difficile was diagnosed through positive glutamate dehydrogenase (GDH) with or without toxin A/B using enzyme immunoassay methods. The prevalence and subtype genetic characteristics of Blastocystis were determined by polymerase chain reaction (PCR) amplification and analysis of the barcode region of the SSU rRNA gene.
RESULTS
The proportion of C. difficile in patients with healthcare-associated diarrhea in this study was 44% (109/248). Among the 109 C. difficile-positive patients, 59 (54.1%, 59/109) tested positive for toxigenic C. difficile, which was considered CDI. Based on the sequence analyses of the barcode region of the SSU rRNA gene, 10.1% (25/248) of the patients were found to be Blastocystis-positive, and three subtypes were identified: ST7 (64%, 16/25), ST1 (20%, 5/25), and ST3 (16%, 4/25). Remarkably, we found five patients with Blastocystis and C. difficile coinfection, and further subtype analysis showed two with ST7, two with ST1, and one with ST3.
CONCLUSIONS
To the best of our knowledge, this is the first study to investigate the subtype distributions of Blastocystis in patients with CDI in Singapore. We found ST7 to be the predominant subtype in diarrheal patients. The pathogenicity of ST7 has been strongly suggested in previous in vitro and mouse model experiments, further confirming its potential pathogenicity to humans.
Topics: Adolescent; Adult; Aged; Blastocystis; Blastocystis Infections; Clostridioides difficile; Clostridium Infections; Coinfection; Cross Infection; DNA, Protozoan; Feces; Female; Genetic Variation; Humans; Male; Middle Aged; Molecular Typing; Phylogeny; Prevalence; Singapore; Young Adult
PubMed: 34030712
DOI: 10.1186/s13071-021-04749-8 -
Scientific Reports Jan 2023Cryptosporidiosis, giardiasis, and blastocystosis are among the most important parasitic diseases common between humans and cats. In addition, there are concerns about...
Cryptosporidiosis, giardiasis, and blastocystosis are among the most important parasitic diseases common between humans and cats. In addition, there are concerns about the possible transmission of zoonotic parasites from infected cats to humans. Hence, we investigated the molecular epidemiology of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. in stray and household cats and cat owners. Our study was performed on 132, 33, and 33 fecal samples of stray and household cats, as well as cat owners in Tehran, Iran. Cryptosporidium spp. was identified using a nested PCR targeting the small subunit ribosomal RNA gene (SSU rRNA) and sequencing the internal amplified fragments. Furthermore, to perform multilocus genotyping of G. duodenalis, the ß-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes were amplified to assess the DNA of G. duodenalis in the fecal samples of cats and cat owners. In addition, Blastocystis was detected by targeting the SSU rRNA gene, and the subtypes of Blastocystis were determined via the sequencing of amplicons. Cryptosporidium felis and Cryptosporidium canis were detected in seven stray cats (5.3%) and one household cat (3%). The bg gene of G. duodenalis was amplified and successfully sequenced in two (1.5%) stray cats and revealed assemblages F and B of G. duodenalis. Sequencing and phylogenic analysis of SSU rRNA gene nucleotide sequences of Blastocystis detected ST5 and ST10 in stray cats (1.5%), ST1 in household cats (9.1%), and ST1, ST2, ST3, and ST7 in owners (30.3%). The low prevalence of Cryptosporidium, Giardia and Blastocystis in cats and the presence of species/assemblages/subtypes with limited zoonotic potential indicate that cats had a minor role in their owners' infection in the investigated population. However, the presence of zoonotic protozoa in cats suggests the necessity of special attention to high-risk individuals during close contact with cats. Therefore, it is recommended that veterinarians, physicians, and urban managers plan to prevent, control, or treat these parasites to help the urban community live healthily alongside cats.
Topics: Humans; Animals; Cats; Giardiasis; Giardia; Cryptosporidium; Cryptosporidiosis; Blastocystis; Iran; Giardia lamblia; Feces; Prevalence; Genotype
PubMed: 36707690
DOI: 10.1038/s41598-023-28768-w -
Parasite Epidemiology and Control Nov 2021Although sp. is one of the most prevalent intestinal parasites worldwide, its role as a pathogen remains unclear. The use of molecular techniques to assess the genetic...
Although sp. is one of the most prevalent intestinal parasites worldwide, its role as a pathogen remains unclear. The use of molecular techniques to assess the genetic heterogeneity of sp. has become important to understand its function in some intestinal pathologies and if it is a key component of intestinal microbiota. Spondyloarthritis is a group of immune-mediated autoinflammatory diseases in which microbial dysbiosis in the gut (including parasites, bacteria and fungi) and intestinal inflammation are common features apparently associated with the pathophysiology of these disorders. This study included 74 patients diagnosed with spondyloarthritis and 57 systemically healthy individuals (included as controls), who were screened for intestinal parasites. sp. was detected in 68% and 73% of the patients with spondyloarthritis and controls, respectively. In faecal samples positive for sp., an 18S rRNA gene fragment of sp. was amplified and sequenced to identify their genetic sub-types. Patients with spondyloarthritis showed similar frequencies of ST1, ST2 and ST3 subtypes of sp. (30% each). The same subtypes were observed in controls, wherein almost 60% of the samples showed ST3. In addition, ST6 was found only in one sample from each group. ST1 subtype showed the greatest genetic variability. Although the same subtypes were detected in both patients with spondyloarthritis and controls, subtype prevalence studies conducted in Colombia indicate an association between ST3 and individuals with irritable bowel syndrome. This opens an interesting research avenue to further study of the epidemiology of sp. and its possible relationship with intestinal conditions in immunocompromised patients.
PubMed: 34667886
DOI: 10.1016/j.parepi.2021.e00227 -
Clinical Microbiology Reviews Oct 1996Blastocystis hominis is a unicellular organism found commonly in the intestinal tract of humans and many other animals. Very little is known of the basic biology of the... (Review)
Review
Blastocystis hominis is a unicellular organism found commonly in the intestinal tract of humans and many other animals. Very little is known of the basic biology of the organism, and controversy surrounds its taxonomy and pathogenicity. There morphological forms (vacuolar, granular, and ameboid) have been recognized, but recent studies have revealed several additional forms (cyst, avacuolar, and multivacuolar). The biochemistry of the organism has not been studied to any extent, and organelles and structures of unknown function and composition are present in the cells. Several life cycles have been proposed but not experimentally validated. The form used for transmission has not been defined. Infections with the organism are worldwide and appear in both immunocompetent and immunodeficient individuals. Symptoms generally attributed to B. hominis infection are nonspecific, and the need for treatment is debated. If treatment appears warranted, metronidazole is suggested as the drug of choice, although failures of this drug in eradicating the organism have been reported. Infection is diagnosed by light microscopic examination of stained smears or wet mounts of fecal material. Most laboratories identify B. hominis by observing the vacuolar form, although morphological studies indicate that other forms, such as the cyst form and multivacuolar form, also should be sought for diagnosis.
Topics: Animals; Antiprotozoal Agents; Blastocystis Infections; Blastocystis hominis; Disease Transmission, Infectious; Drug Therapy, Combination; Humans; Microscopy, Electron; Prevalence
PubMed: 8894352
DOI: 10.1128/CMR.9.4.563 -
Acta Parasitologica Jun 2022Blastocystis is a common enteric human parasite of non-conclusive pathogenicity which may be determined by subtype (ST) variation. Colorectal cancer (CRC) is considered...
PURPOSE
Blastocystis is a common enteric human parasite of non-conclusive pathogenicity which may be determined by subtype (ST) variation. Colorectal cancer (CRC) is considered one of the primary causes of cancer mortality. Blastocystis ST7 has been shown to reduce beneficial intestinal microbiota and may exacerbate CRC. This study assessed the possible association between Blastocystis STs and CRC in comparison to non-cancer patients.
MATERIAL AND METHODS
A total of 200 fecal samples were obtained from CRC (100) and non-CRC (100) individuals attending Beni-Suef University Hospital, Egypt. Blastocystis was searched for in all samples using microscopy and culturing. Positive subculture samples were genetically sequenced and subtyped using conventional polymerase chain reaction (PCR). Blastocystis STs were determined by sequencing and a phylogenetic tree was created. Related patient characteristics and tumor stages were analyzed for association with presence of Blastocystis.
RESULTS
Blastocystis was identified in 52% and 42% of CRC and non-cancer individuals, respectively. ST1, 2, and 3 were isolated from both cancer and non-cancer individuals; however, for the first time, ST7 was only isolated from CRC stool samples with significant association. Associated patient characteristics were evaluated as predictors.
CONCLUSION
Blastocystosis is highly prevalent in CRC patients, predominantly in the latest CRC grades and stages. To the best of our knowledge, this is the first study to report the identification of Blastocystis ST7 in CRC patients. To determine whether certain STs of Blastocystis are associated with CRC would require further research, including the role played by gut microbiota.
Topics: Blastocystis; Blastocystis Infections; Colorectal Neoplasms; DNA, Protozoan; Feces; Genetic Variation; Humans; Phylogeny
PubMed: 35067864
DOI: 10.1007/s11686-021-00508-y -
Microbiome Mar 2019Blastocystis is a common gut eukaryote detected in humans and animals. It has been associated with gastrointestinal disease in the past although recent metagenomic...
BACKGROUND
Blastocystis is a common gut eukaryote detected in humans and animals. It has been associated with gastrointestinal disease in the past although recent metagenomic studies also suggest that it is a member of normal microbiota. This study investigates interactions between pathogenic human isolates belonging to Blastocystis subtype 7 (ST7) and bacterial representatives of the gut microbiota.
RESULTS
Generally, Blastocystis ST7 exerts a positive effect on the viability of representative gut bacteria except on Bifidobacterium longum. Gene expression analysis and flow cytometry indicate that the bacterium may be undergoing oxidative stress in the presence of Blastocystis. In vitro assays demonstrate that Blastocystis-induced host responses are able to decrease Bifidobacterium counts. Mice infected with Blastocystis also reveal a decrease in beneficial bacteria Bifidobacterium and Lactobacillus.
CONCLUSIONS
This study shows that particular isolates of Blastocystis ST7 cause changes in microbiota populations and potentially lead to an imbalance of the gut microbiota. This study suggests that certain isolates of Blastocystis exert their pathogenic effects through disruption of the gut microbiota and provides a counterpoint to the increasing reports indicating the commensal nature of this ubiquitous parasite.
Topics: Animals; Bacterial Proteins; Bifidobacterium longum; Blastocystis; Blastocystis Infections; Coculture Techniques; Disease Models, Animal; Feces; Gastrointestinal Diseases; Gastrointestinal Microbiome; Gene Expression Profiling; Gene Expression Regulation, Bacterial; HT29 Cells; Humans; Lactobacillus; Metagenomics; Mice
PubMed: 30853028
DOI: 10.1186/s40168-019-0644-3 -
BMC Microbiology Dec 2017Blastocystis sp. is a unicellular eukaryote that is commonly found in the human intestine. Its ability to cause disease is debated and a subject for ongoing research. In...
BACKGROUND
Blastocystis sp. is a unicellular eukaryote that is commonly found in the human intestine. Its ability to cause disease is debated and a subject for ongoing research. In this study, faecal samples from 35 Swedish university students were examined through shotgun metagenomics before and after travel to the Indian peninsula or Central Africa. We aimed at assessing the impact of travel on Blastocystis carriage and seek associations between Blastocystis and the bacterial microbiota.
RESULTS
We found a prevalence of Blastocystis of 16/35 (46%) before travel and 15/35 (43%) after travel. The two most commonly Blastocystis subtypes (STs) found were ST3 and ST4, accounting for 20 of the 31 samples positive for Blastocystis. No mixed subtype carriage was detected. All ten individuals with a typable ST before and after travel maintained their initial ST. The composition of the gut bacterial community was not significantly different between Blastocystis-carriers and non-carriers. Interestingly, the presence of Blastocystis was accompanied with higher abundances of the bacterial genera Sporolactobacillus and Candidatus Carsonella. Blastocystis carriage was positively associated with high bacterial genus richness, and negatively correlated to the Bacteroides-driven enterotype. These associations were both largely dependent on ST4 - a subtype commonly described from Europe - while the globally prevalent ST3 did not show such significant relationships.
CONCLUSIONS
The high rate of Blastocystis subtype persistence found during travel indicates that long-term carriage of Blastocystis is common. The associations between Blastocystis and the bacterial microbiota found in this study could imply a link between Blastocystis and a healthy microbiota as well as with diets high in vegetables. Whether the associations between Blastocystis and the microbiota are resulting from the presence of Blastocystis, or are a prerequisite for colonization with Blastocystis, are interesting questions for further studies.
Topics: Adult; Biodiversity; Blastocystis; Blastocystis Infections; Feces; Female; Gastrointestinal Microbiome; Humans; Male; Metagenomics; Prevalence; Sweden; Travel; Young Adult
PubMed: 29228901
DOI: 10.1186/s12866-017-1139-7 -
Acta Tropica Apr 2023Blastocystis is an enteric protozoan able to infect humans and a large variety of animal hosts worldwide. It exhibits significant genetic diversity, with at least 17...
Blastocystis is an enteric protozoan able to infect humans and a large variety of animal hosts worldwide. It exhibits significant genetic diversity, with at least 17 subtypes (STs) identified to date, most of which have low host specificity. In the present study, a cross-sectional survey was conducted on Blastocystis infection among humans and domestic animals sharing habitats in northeastern China's Heilongjiang Province, in order to investigate the frequency and subtype distribution and to evaluate the risk of the zoonotic transmission of Blastocystis sp..Results show that the frequency was 10.5% (6/57), and three subtypes (ST1, ST2, and ST3) were found in humans; in animals, the frequency was 17.9% (46/257), and six subtypes (ST1, ST3, ST5, ST7, ST10, and ST26) were detected. A significant association between Blastocystis sp. infection and eating unwashed vegetables and fruits was found (P = 0.007). We found no effect on gender, age and season on Blastocystis sp. colonization. Phylogenetic analysis showed that Blastocystis ST7 sequences from chicken in two geographical locations formed two distinct clades. Alleles were identified using the Blastocystis 18S database, and a total of 10 different alleles were found in seven STs. Overlap of STs in humans and domestic animals (pig or cattle) was observed in Dongfanghong village. The findings of potentially zoonotic subtypes in domestic animals suggest that these animals may serve as reservoirs of human Blastocystis sp. infections. Multisectoral cooperation is needed to slow down the transmission of Blastocystis in domestic animals, minimize environmental contamination by Blastocystis cysts, and increase molecular epidemiological surveillance of Blastocystis sp. in humans and animals.
Topics: Humans; Animals; Cattle; Swine; Blastocystis; Animals, Domestic; Phylogeny; Cross-Sectional Studies; Genetic Variation; Blastocystis Infections; China; Feces; Prevalence
PubMed: 36706827
DOI: 10.1016/j.actatropica.2023.106844 -
Biology May 2022Blastocystis is a common human intestinal protozoan parasite. Little is known about its prevalence in echinococcosis. This study tested whether Echinococcus...
Blastocystis is a common human intestinal protozoan parasite. Little is known about its prevalence in echinococcosis. This study tested whether Echinococcus multilocularis infection would increase host susceptibility to Blastocystis. A total of 114 fecal samples (68 hydatid disease patients and 46 healthy people) were collected from Tibetans in the Qinghai province in China. The presence of Blastocystis was identified by sequencing of the small subunit (SSU) rRNA gene. Balb/c mice were co-infected with Blastocystis and E. multilocularis and tested for host susceptibility to Blastocystis. The overall Blastocystis prevalence was 12.3%; 16.2% in the patients and 4.4% in healthy people (p < 0.05). Sequence analysis identified three known Blastocystis genotypes, including ST1, ST2, and ST3, and one unknown genotype. Experimental dual infection significantly reduced mouse survival rate (20%), induced more severe signs, and increased intestinal damages with a higher intestinal colonization level of Blastocystis. The mouse model showed that E. multilocularis infection increases host susceptibility to Blastocystis. Our study shows a significantly higher prevalence of Blastocystis in patients with liver echinococcosis and reveals that non-intestinal E. multilocularis infection increases host susceptibility to the Blastocystis. Our results highlight that E. multilocularis infection is associated with Blastocystis. These findings remind us that more attention should be paid to the gut health of the patients with a helminth infection during clinical patient care.
PubMed: 35625501
DOI: 10.3390/biology11050773 -
Parasitology Research Nov 2020Blastocystis is the most frequently observed eukaryotic gastrointestinal symbiont in humans and animals. Its low host specificity and zoonotic potential suggest that... (Review)
Review
Blastocystis is the most frequently observed eukaryotic gastrointestinal symbiont in humans and animals. Its low host specificity and zoonotic potential suggest that animals might serve as possible reservoirs for transmission. The prevalence and subtype distributions of Blastocystis sp. in animal populations in Southeast Asia, a hotspot for zoonotic diseases, are reviewed. Recommendations for future research aimed at understanding the zoonotic role of Blastocystis are also included. Seven countries have, so far, reported Blastocystis infection in various animals, such as livestock, poultry, companion animals, and non-human primates. Pigs were the most studied animals, and there were records of 100% prevalence in pigs, cattle, and ostriches. Using polymerase chain reaction (PCR)-based approaches, twelve Blastocystis sp. subtypes (STs), namely ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST8, ST9, ST10, ST12, and ST14 have been recognised infecting animals of Southeast Asia. ST1 and ST5 were the most frequently identified, and Malaysia observed the most diverse distribution of subtypes. Further investigations on Blastocystis sp. in various animal hosts, using adequate sample sizes and uniform detection methods, are essential for a better understanding of the distribution of this organism. Detailed genome studies, especially on STs shared by humans and animals, are also recommended.
Topics: Animals; Asia, Southeastern; Blastocystis; Blastocystis Infections; Cattle; Cattle Diseases; Humans; Poultry; Poultry Diseases; Prevalence; Primates; Swine; Swine Diseases; Zoonoses
PubMed: 32951145
DOI: 10.1007/s00436-020-06828-8