Trends in Blastocystis Research

I thought I'd post two current conference abstracts to exemplify some of the trends in  Blastocystis research.

The first is from Dr Pauline D Scanlan, who will be speaking at 15th International Congress of Protistology currently taking place in Prague. Go here for more info about the meeting.

In the symposium 'The eukaryome, bringing protists into the spotlight of microbiome research' taking place today, Pauline will be giving a talk with the title:

Inter-Kingdom Interactions in the human gut microbiome-the prevalence of the intestinal protist Blastocystis is linked to host age, antibiotic use and gut bacterial diversity and composition

and the abstract reads like this:

The human gut is host to a complex microbial ecosystem that plays a central role in host health. In addition to bacteria, viruses and archaea, the gut microbiota includes a diversity of fungal and protist species that are collectively referred to as the gut ‘eukaryome’. Although research into the gut eukaryome is in its infancy, emerging data indicates that the intestinal protist Blastocystis is perhaps the most common member of the human gut eukaryome worldwide. Despite its association with intestinal disease, asymptomatic carriage is common with Blastocystis frequently observed in surveys of the healthy adult gut microbiome. Furthermore, Blastocystis is less prevalent in chronic diseases such as Irritable Bowel Syndrome compared to healthy controls. Antibiotic administration significantly reduces Blastocystis prevalence rates between case and controls groups with the reduction in Blastocystis prevalence in the antibiotic treated group possibly due to direct effects on Blastocystis and/or secondary loss due to loss of bacteria that Blastocystis interacts with. In support of this latter hypothesis, data showing correlations between the presence of Blastocystis and specific features of the bacterial component of the gut microbiome (high diversity and a specific bacterial composition) are suggestive of inter-kingdom interactions between bacteria and Blastocystis in the gut microbiome. Blastocystis is less prevalent in infant populations relative to contemporaneous adult populations indicating that Blastocystis is not adapted to the infant gut. Given the difference in microbiome composition and diversity in infants compared to adults perhaps Blastocystis requires a more adult-like gut microbiome for successful colonisation. Collectively, emerging data suggests that successful colonisation of the gut by Blastocystis is linked to the composition and diversity of the bacterial fraction of human gut microbiome. Consequently, interactions between Blastocystis and bacteria in the gut microbiome may account for some of the variation in prevalence rates observed across age, health and geography.

 
Along similar lines, I will be giving a talk at the EMBO conference 'Anaerobic protists: Integrating Parasitology with mucosal microbiota and immunology' running from 31 AUG to 03 SEP in Newcastle, UK. You can read about the conference here.

The title and abstract of my talk are as follows:

The diversity of the most common intestinal protists, Blastocystis and Dientamoeba, and their interactions with the microbiota: what role in health and disease?

The integration of DNA-methods in Clinical Microbiology has enabled a more detailed and accurate snapshot of the protists colonising and infecting our guts. Parasites like Blastocystis and Dientamoeba are much more common than previously known, when detection relied mainly on microscopy of faecal concentrates and smears only.

While Dientamoeba isolated from humans exhibits very little genetic variation across the small subunit ribosomal gene, Blastocystis displays a perplexing amount of genetic heterogeneity, and nine subtypes, which are arguably separate species, have been found in humans. Subtypes 1 to 4 account for about 95% of human Blastocystis carriage.

It is expected that over 1 billion people are colonised by Blastocystis, and based on DNA-based detection, prevalence figures of up to 100% have been reported in developing countries. Conversely, the prevalence of Blastocystis appears relatively low in e.g. the US, and it has been suggested that the low prevalence is indicative of the defaunation of indviduals adapting a Westernized life style.

In a developed country like Denmark, the prevalence of Blastocystis and Dientamoeba is highest in individuals without gastrointestinal, while the prevalence of these parasites is lower in patients with functional and organic bowel disease, suggesting that these parasites are in fact markers of gastrointestinal health.

This is also in part exemplified by recent independent data linking high gut microbiota diversity to the presence of these parasites. Certain bacterial populations appear to be linked to parasite carriage, and studies are emerging that try to look into the association between these parasites and the remaining gut microbiota.

Moreover, higher age appears to be linked to Blastocystis colonisation. Blastocystis is more common in older children and adults, while in younger children, Dientamoeba is much more common.

Whether these parasites are able to modulate gut microbiota structure and function remains unknown, and it also remains to be demonstrated whether certain microbiota communities and/or metabolites are required for successful establishment of these parasites. More research data on these topics will inform future advances in probiotics in particular and gut microbiota manipulation in general.

 Thanks for your time.

It's official - The 2nd International Blastocystis Conference!

It's been a while, but I hope the wait has been worth the while!

On behalf of the organisers, who currently include Juan-David Ramírez, Funda Dogruman-Al, and myself, we would now like to announce the dates, venue, and speakers for the 2nd International Blastocystis Conference! Feel free to be mesmerised!

Juan-David Ramírez just sent me the 'teaser' below - and this blog is an obvious place to share it.
We are very happy that so many "heavy Blastocystis researchers" have accepted our invitation to participate! However, we already now know that we will be missing some very important ones. Well, you can't have it all, and we're absolutely sure that the event will be a BLAST(ocystis)!

There will be a two-day workshop (9th–10th of October) followed by a two-day conference (11th–12th of October). On the Friday, the 13th of October, it will be possible to participate in a one-day sightseeing event in Bogotá.

So, if you haven't done it already, make sure that you sign up for notifications from the Blastocystis Parasite Blog (here or on Facebook) in order to keep up with the latest information on abstract submission deadlines, programme, practicalities, travel grants, etc.

We are also on the lookout for sponsors, so if you have any suggestions, please contact me.

We are looking very much forward to seeing you in Bogotá in 2018!

Blastocystis PhD thesis from Iraq

My colleague, Dr Haitham Sedeeq Albakri (Assistant Professor at Department of Microbiology, College of Veterinary Medicine, University of Mosul), recently defended his PhD thesis  on 'Isolation and Genotyping of Blastocystis hominis in Human and Different Animals in Erbil Province'. His work was supervised by Prof Dr Abdul Aaziz Jameel Al-Ani.

Haitham wrote me and asked if I could publish the summary on my website, so here goes:

Blastocystis is an enteric unicellular anaerobic protozoan that presents in the digestive system of the humans and different animal hosts including cattle, sheep, goats, pigs, dogs, cats and birds as well as wild animals. Blastocystis causes digestive system disorders especially the irritable bowel syndrome, while animals are considered as reservoir and infective hosts. In Iraq, few morphological studies related to Blastocystis have been done in human only, but not animals. Therefore, the study aimed to detect the presence of Blastocystis in human and animal hosts, in addition to study the morphological and genetic characteristics of this protozoan. In this present study, a total of 292 stool samples have been examined for the presence of Blastocystis, the samples were distributed as follows: humans 62, cattle 81, sheep 78, dogs 21 and cats 50. Wet mount preparation, trichrome staining and culture methods were used to study the morphological characteristics of Blastocystis. In addition, molecular characteristics have been studied by polymerase chain reaction (PCR) using universal primers to detect the presence of the Blastocystis, and subsequently subtyping of positive samples using 10 pairs of subtype-specific primers. Blastocystis also have been characterized by restriction fragment length polymorphism (RFLP) method using HinfI. Finally, DNA barcoding method has been used as a more accurate and recommended method for subtyping. The results showed that Blastocystis has been detected using wet mount preparation method in 71 (24.3%) out of 292 samples collected from all hosts including human, cattle, sheep dogs and cats. While 17/62 (27.4%), 19/81 (23.5%), 14/78 (17.9%), 3/21 (14.3%) and 18/50 (36.0%) samples were positive in human, cattle, sheep dogs and cats, respectively. The detection percentages were higher when culture method was used and 98 (33.6%) were positive out of 292 tested samples. While 28/62 (45.2%), 31/81 (38.3%), 25/78 (32.1%), 2/21 (9.5%) and 12/50 (24.0%) samples were positive in human, cattle, sheep dogs and cats, respectively. The molecular methods revealed that all cultured samples were positive using universal primers with product size 1780 bp. While positive samples subtyped using specific primers into ST3a and ST3b in humans, ST5 and ST6 in cattle and ST6 in sheep, ST1a in dogs and ST5 in cats. The RFLP technique classified the Blastocystis into seven genotypes; type I, II and III in humans, type IV, V and VI in cattle and only one type, VII, in sheep. Whereas, DNA barcoding method showed that ST2 and ST3 present in humans, ST14 in cattle and ST5 in sheep, these subtypes represent 9 isolates of Blastocystis sp. that have been successfully submitted to the GenBank of the NCBI, including 4 isolates in human, 2 isolates in cattle and 3 isolates in sheep. In conclusion, this is the first morphological and genetic study of Blastocysts in humans and animal hosts in Iraq. It is also the first time that culture method has been used in Iraq for diagnosis of this protozoan. Additionally, it is the first time that molecular characterization of different local subtypes has been confirmed in Iraq. Further studies are needed to include morphological and genetic characteristics in other animal hosts and to study the relationship between human and animal isolates in different geographical areas in Iraq, in addition to investigate the relation between Blastocystis with irritable bowel syndrome in humans.

I believe that this is the first study to include Blastocystis subtype data from Iraq. I also believe that the thesis was written mostly in Arabic. Dr Albakri's email address is haitham_albakri[at]yahoo.com