Showing posts with label Blastocystis. Show all posts
Showing posts with label Blastocystis. Show all posts

Saturday, November 10, 2018

2nd International Blastocystis Conference Wrap-Up - Part III

I asked around for some more take-home messages from a couple of the keynote speakers present at the 2nd International Blastocystis Conference last month in Bogotá. Here's a summary:

Kevin Tan:
  • Blastocystis is a species complex and as such, it is difficult to generalize on its roles in health and disease.
  • Studies are revealing that intra-subtype variations are associated with different phenotypes, so it is likely that we will require more resolution (allelic) when studying the effects of Blastocystis on the host.
  • Recent metagenomics studies on stools of healthy individuals associate the presence of Blastocystis with a diverse bacterial microbiota, but more studies are required on diseased groups to identify their possible associations with rare/ pathogenic isolates (e.g. ST7 isolates).
  • Recent work on rodent models are shedding light on possible pathogenic effects of acute Blastocystis infections.
  • More studies on the cell and molecular biology of Blastocystis are required to better understand the molecular basis for Blastocystis-host interactions (identify virulence factors, adaptation strategies etc).
  • It is very likely that more surprises are in store for the curious and observant Blastocystis researcher!

Kevin Tan giving his keynote

Kevin Tan taking questions - here probably expanding on Blastocystis ploidy...



Andrew Roger:
  • We shouldn’t try to generalize about characteristics of ‘Blastocystis’ based on studies of individual isolates. This is a category error — Blastocystis comprises many many different organisms with different genetic makeups. There is variation not just between subtypes, but within subtypes. So we shouldn’t say “Blastocystis is a commensal/parasite” because different Blastocystis isolates could be commensals or parasites depending on the host, the genetic makeup of the parasite and the microbiota with which they interact.
  • In microbiome studies, colonization with Blastocystis in general seems to correlate with a different composition of the prokaryotic microbiota in hosts.
  • We know virtually NOTHING about the basic cell biology of Blastocystis (Kevin Tan’s group is making important inroads into understanding this).
  • We know virtually NOTHING about how Blastocystis interacts with (or responds to) other microbes and the host immune system.
  • There may be an important impact of host diet on Blastocystis colonization and ‘behaviour'.
  • The diversity of Blastocystis in humans and animals is huge — new lineages are being continuously revealed.


Andrew Roger about to give his keynote

Andrew Roger taking questions from the audience

Friday, October 19, 2018

2nd International Blastocystis Conference Wrap-Up - Part II

So, a lot of people would like to know about the take-home messages from the recent 2nd International Blastocystis Conference in Bogotá. There were many, and I might develop one more post to make room for more.

The first - and most important - thing I'd like to emphasise is that the community interested in Blastocystis is growing. And we're seeing a clearly multidisciplinary approach to studying the parasite. I think that this is what we need. The initial ideas about having Blastocystis-specific conference were developed by Funda Dogruman-Al and myself, and we both have a background in clinical microbiology. We have realised that in order to make sense of Blastocystis in a clinical microbiology (and infectious disease) context, we need research input from bordering fields, such as biology (genomics, cell biology, etc.), veterinary medicine (host specificity and impact of Blastocystis on animal health), gastroenterology (connection to microbiota and the extent of Blastocystis being involved in functional and inflammatory bowel diseases), bioinformatics (processing NGS data such as those pertaining to the profiling of gut microbiota communities), and ecology (people who are used to study interactions between organisms). At the conference, I believe that all (or at least most) of these fields were represented.

I was also thrilled to realise that many researchers have now adapted to the subtype terminology, - and even the allele terminology appears to be useful and pragmatic.


Status on the Blastocystis genome project. Slide by Andrew Roger.

Andrew Roger highlighted that the genomes of Blastocystis are more different than the genomes of human and mouse! Well-annotated genomes are available for ST1, ST4, and ST7, while draft genomes are available for subtypes 2, 3, 6, 8 and 9. 

 
What use are genomes? Summary provided by Andrew Roger.


Animal experimental modelling is possible. We know that rats can be colonised/infected by Blastocystis ST1 strain from a human and shed cysts in stool for more than one year.

Blastocystis is one of the few parasites that are really easy to culture and easy to get by. If we can learn to induce cysts in culture, these can be separated by sucrose gradient centrifugation or other methods and used for inoculation into volunteers, pigs, or rats, for instance. This can be used to study the impact of Blastocystis on the host, including immune system and gut microbiota. Baseline microbiota profiling is necessary prior to inoculation to know about the background variation in study individuals.

In terms of Blastocystis and gut microbiota: Since we published our conspicuous observations in 2015, many researchers have now corroborated our findings: Blastocystis is typically linked to increased microbiota richness and diversity; - something, which is generally considered a benefit and which is linked not only to gut health, but also to leanness. Especially the negative association between Blastocystis and Bacteroides has been highlighted by many now. It will be very interesting to learn why this is so. It also seems that Blastocystis are more common in individuals with a gut microbiota dominated by strictly anaerobes rather than facultative aerobes.

Faecal microbiota transplantaion (FMT): The recommendation of excluding FMT donors based on the finding of Blastocystis came up many times and was discussed in the context of the microbiota studies. It appear relevant to investigate further whether FMT donors should really be dismissed if they are Blastocystis-positive.

Some of the take home messages from Raul Tito Tadeo's talk.

In many animal groups, Blastocystis is a very common finding. These include mostly omnivores or herbivores. On the contrary, Blastocystis is very rare in strict carnivores, with no consistency in subtype distribution, indicating that these animals are not natural hosts of Blastocystis.The Blastocystis incidentially found in these hosts might stem from the prey that they have eaten.

Finally, I wish to highlight that there are excellent resources available from the pre-conference workshop, including an R script for microbiota analysis, and some tools for Blastocystis genome annotation. Please visit my previous blog post for links to these.

We cannot totally dismiss pathogenicity of Blastocystis; if existing, it may involve both strain- and host-specific factors.

And.... it's out: The time and venue for the 3rd International Blastocystis Conference will be Crete in 2021 (possibly June), with Eleni Gentekaki and Anastasios Tsaousis being involved in both the scientific and local organising committees... ! Please mark you calendars!

Andrew Roger, Raul Tito Tadeo, Kevin Tan and myself (taking the picture) enjoying some Club Colombia.


Monday, October 15, 2018

2nd International Blastocystis Conference Wrap-Up - Part I

The 2nd International Blastocystis Conference has been completed with great success. It was a very worthy sequel to the first conference in Ankara back in 2015, attracting about 100 delegates.


The Scientific Committee (image above) consisted of Prof Funda Dogruman-Al (main organiser of the 1st International Blastocystis Symposium), Senior Scientist Rune Stensvold, and Associate Prof Juan-David Ramírez González, who also headed the local organising committee (LOC; image below).



We are all very thankful to Juan-David and his colleagues, the entire LOC, the Universidad del Rosario in Bogotá and La Fontana Hotel, which provided an excellent framework with premium facilities.


The Faculty can be seen on the image below. From left to right, it's Rodolfo Casero, [Magdalena Maria Martinez Agüero, Director of Investigation and Innovation, Facultad de Ciencias Naturales Y Matemáticas, Universidad del Rosario], Andrew Roger, Rune Stensvold, Hisao Yoshikawa, Raul Tito Tadeo, Monica Santin-Duran, Funda Dogruman-Al, Kevin Tan, and Juan David Ramirez Gonzalez. Workshop sessions and keynote lectures were developed and given by members of the Faculty.


The workshop took place on 9–10 October and covered sessions on diagnosis (microscopy, culture, PCR, etc.), in vivo and in vitro experimental models, subtype calling from DNA sequence data, gut microbiota analysis (NGS data processing in R), genomics and evolution (introduction to Blastocystis genomics and resources available), and theoretical topics linked to epidemiology, clinical microbiology and infectious disease issues.

Some of the workshop participants and Faculty members

The conference took place on 11–12 October and consisted of nine keynote lectures delivered by the Faculty members, 12 oral presentations and 22 poster presentations.

The award for the best oral presentation was given to Justinn Hamilton who is an ecologist now based at University of Copenhagen for his talk 'Exploring interactions between Blastocystis sp., other intestinal parasites and the gut microbiomes of wild Chimpanzees (Senegal): Not-so-friendly old-friends-hypothesis'.

The award for the best poster presentation went to David Carmena's group for the impressive study 'Molecular epidemiology of Blastocystis sp. in asymptomatic school children from Madrid, Spain'.

The workshop programme can be viewed/downloaded here, and the conference programme is available here. The poster programme is available here.
Please go here to browse conference proceedings, and here for workshop guidelines.
Stay tuned for Wrap Up Part II and III, which will include more photos and some of the take-home messages from the conference.

Please also follow @Blastocystis on Twitter and and the International Blastocystis Network Facebook page for updates/pictures from the conference.

Monday, October 1, 2018

2nd International Blastocystis Conference just around the corner!

Need I remind you that the 2nd International Blastocystis Conference is just around the corner!

You can find an updated list of speakers and the entire programme here.

It will be a total of 4 (f-o-u-r!!) days of discussion of Blastocystis research and sharing of experience in terms of e.g. diagnostics, typing, and genome sequencing.

We'll be covering most areas, including clinical and public health significance, host specificity, genetic diversity, genomics, metagenomics/amplicon-based sequencing, Blastocystis in the clinical microbiology setting, etc. And of course there will be a lot of survey data.

Need I say that I look forward to this?

:-)

I hope to see quite a few of you in Bogotá!

Please follow the International Blastocystis Network (IBN) on Facebook and @Blastocystis on Twitter. We will be posting there during the conference....

(IBN stimulates and promotes activities related to research in Blastocystis. IBN is a member of the World Federation of Parasitologists)

Tuesday, July 10, 2018

Updates on 2nd International Blastocystis Conference

Three months until kick-off of 2nd International Blastocystis Conference in Bogotá!

A couple of updates:

  • Abstract submission deadline has been postponed to 15th of August 2018
  • We have had a couple of speaker cancellations. Drs Pauline Scanland and Katerina Pomajbikova will not be able to participate. Hopefully, we'll be blessed by their presence at the next big Blasto event. Instead, Drs Raul Tito-Tadeo and Hisao Yoshikawa have very kindly accepted to give keynote lectures and lead workshop sessions. And so we will still have a great event!
For more information on workshop and conference, please visit the official conference website here.

Since it's summer here in Europe, and since I love Phlox, I thought, I'd attach a couple of images that I received yesterday from my dear friend Jaco Verweij.


Tuesday, July 3, 2018

Experimental models for Blastocystis research - new paper out!

Experimental models are critical to advancing our knowledge on the role of Blastocystis in health and disease.

We have now published our work led by Dr Katerina Pomajbikova on the suitability of the rat as a model of Blastocystis colonisation. We observed that the rats were able to sustain the colonisation for more than one year, when a ST1 strain isolated from a human was used.

Next step could now be to monitor gut microbiota before and after challenge with Blastocystis cysts and look for changes at both individual and community level,, changes in alpha and beta diversity, etc.

The paper is free for download here until August 19, 2018.

Friday, June 22, 2018

Updates on 2nd International Blastocystis Conference in Bogotá!

Hi everyone,

There's only little more than three months before the kick-off of our 2nd International Blastocystis Conference! And as in the case of our 1st conference in Ankara in 2015, participants are in for a real treat! I simply don't know where to begin... !



Well, for starters, here's the hotel in which the conference will take place (11–12 October). It's the Hotel Estelar La Fonata in Bogotá! I think it looks amazing!

Prior to the very conference (9–10 October), there will be a two-day workshop at Universidad del Rosario - Quinta De Mutis.

Please go to the conference website and find more information: http://www.urosario.edu.co/Blastocystis/en/home/

The line-up of faculty members is impressive; again, please visit website to update yourself with workshop leaders and keynote speakers.

We will be dealing with anything from diagnostics to genomics, from epidemiology to cell biology, from experimental models to phylogenetics!

There will be plenty of Colombian coffee to sample and you might also with to sign up for the gala dinner!

So, don't miss out on the opportunity to put yourself into the very epicentre of Blastocystis research and experience the dynamic city of Bogotá!

Importantly, the deadline for abstract submission is 1st of July, so please everyone: Get your act together - submit your abstract today and support us with your presence and your enthusiasm with regard to the most common parasite in the human gut: Blastocystis!

SEE YOU THERE!!!

Image result for sun emoji

Wednesday, March 21, 2018

More on Blastocystis and Gut Bacteria...

As an appropriate follow-up on yesterday's post, I feel like guiding your attention to the paper by Laforest-Lapointe and Arrieta from University of Calgary, Canada with the title 'Microbial Eukaryotes: a Missing Link in Gut Microbiome Studies', which elaborates on some of the issues that we have already been highlighting several times in the past.

Nevermind, in their article, which just appeared in the ASM-based journal "mSystems", they speculate that the reason for the observed link between Blastocystis colonisation and increased bacterial diversity (which was mentioned several times in the paper that I referred to yesterday) might be due to predation by Blastocystis on bacteria, a process which selects for higher diversity. They argue that

"In the absence of Blastocystis, a strong bacterial competitor dominates the community, which limits species richness and community evenness; when [Blastocystis is] present, its predation on abundant bacterial taxa lowers the competition for nutrients and space, which leads to an increase in bacterial richness and community evenness."

Since predation on bacteria by Blastocystis has only been documented once (I believe) to date, the authors are right in encouraging colleagues to study engulfment of bacteria by Blastocystis.

Those of us who take a special interest in the public health impact of common intestinal parasites and who work in the field of clinical microbiology and infectious diseases might benefit from taking some lessons from experts in 'food web theory' and micro- and macroecology.

The article can be accessed here.

Tuesday, March 20, 2018

Associations Between Intestinal Parasites and Bacteria

For those interested in exploring the presence/absence of intestinal parasites in a gut microbiome context, Dr Mark van der Giezen and I did this small opinion paper for Trends in Parasitology. In it, we summarize data from studies looking at the associations between single-celled intestinal (luminal) parasites and gut bacteria, and we tried to come up with a hypothesis for the factors governing the presence/absence of e.g. Blastocystis.

The paper just appeared online, and you can access it here.



Wednesday, February 21, 2018

PhD position available in Pauline's lab

Message from Dr Pauline D Scanlan (view personal website here):


Friday, October 13, 2017

Official Poster for the 2nd International Blastocystis Conference

Thanks to Juan-David Ramirez Gonzales and his colleauges, the official poster for the 2nd International Blastocystis Conference is now available.

I put it on Google Drive as a pdf file, which you can download here. Please share it on facebook. Please also print it and use it to adorn your institutes, hospital departments, offices, canteens, homes, etc... Thanks!



Monday, July 31, 2017

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.