Showing posts with label rickettsia. Show all posts
Showing posts with label rickettsia. Show all posts

Wednesday, October 29, 2014

This Month in Blastocystis Research (OCT 2014) - Trick or Treat Edition

Over the past 30 days I've hardly had any time to focus on Blastocystis. I've been busy preparing for and attending UEGWeek 2014, preparing abstracts for next year's ECCMID conference in Copenhagen, and I've also put a lot of effort into preparing proposals for this round of grant calls from the Danish Council for Independent Research

Among other things, we are applying for money to develop DNA-probe based diagnostics, including a unique software, for use in the clinical microbiology lab that entirely circumvents the use of PCR (and thereby amplification bias) and that screens sequence data in real-time. An issue with current state-of-the-art in the area is that no software is available to relevantly and reliably handle the tons of sequence data that next/third/fourth generation sequencing devices are capable of producing. The proposed software will have a vast application range, applicable not only to clinical microbiology but also other areas of microbiology, such as food control, water sanitation, and monitoring of microbes in oil, soil, etc.

We are applying for about 270.000 Euros, and although this doesn't sound like an awful lot of money, competition is extremely fierce for this type of grant (although I'm not sure that the competition has to do exclusively with the scientific and innovative quality of the proposal...). So, let's see if it's going to be trick or treat!

Earlier this month, I was honoured to give a talk in Padova at the XXX National Congress of the Italian Society of Protistology on Blastocystis and its role in health and disease. I also got the chance to listen to some of the remarkable talks delivered by passionate colleagues of the society. There was quite a lot on endosymbionts of protists. The development of mitochondria in eukaryotic cells is a classical example of endosymbiosis; however, there are numerous examples of e.g. bacteria infecting protists, including the parasitic ones. Legionella, for instance, may be found in Acanthamoebaknown to host a variety of bacterial endosymbionts. Along the same lines, I wish that studies could be made to look up potential endosymbionts in Blastocystis; endosymbionts which may confer disease, and the varying/unstable presence of which might explain the irregularity in symptoms reported by Blastocystis carriers? The question about endosymbionts in Blastocystis is interesting not only from a metabolic and horizontal gene transfer point-of-view, but also in the perspective of Blastocystis potentially serving as a vector, a vehicle for transmission of bacteria and maybe viruses... A nice paper on endosymbiotic associations within protists is available for a free download here. Rickettsia, for instance, are obligate intracellular bacteria found as endosymbionts in different types of eukaryotes, including amoebae, but also in endothelial cells (which are not phagocytic by nature, similar - presumably - to the case of Blastocystis), and some of these rickettsia are  known as causes of spotted fever and typhus. I think that Zierdt is the only one until now who has studied endosymbiosis in Blastocystis...

After the congress in Padova, I got a chance to pay my first visit ever to Venice, which was nothing short of brilliant.

Venice, October 2014.

I did have an hour here and there, however, to look up newest 'releases' on Blastocystis, and I'm just going to highlight a few of them.

Unfortunately in Russian and not available for download on any of the servers that I can access, there's a paper describing the finding of dividing (i.e. alive) forms of Blastocystis in a liver abscess in an immunocompromised woman. The question here is of course, did the parasite end up here by chance (fistula and/or secondary to bacterial invasion?) or by independent invasion? Hope to receive a copy of the paper at some point... and a translation!

There is a paper in a journal called 'Case Reports in Medicine' on what is called a co-infection of Schistosoma and Blastocystis in a 37-year-old male with chronic kidney disease, in whom Blastocystis was speculated to be the cause of chronic IBS-like symptoms. However, there is a number of issues that I would like readers of the paper to focus on: Apparently, the patient had Schistosoma mansoni detected in the urine suggesting schistosomiasis of the bladder. But how was Schistosoma detected? It doesn't say. Was it by microscopy? The patient was ab-positive, but still intestinal schistosomiasis was not ruled out (by e.g. PCR on faecal DNA, microscopy for ova and parasites, rectal biopsy, etc.). The patient responded well to praziquantel treatment and got rid of symptoms, including the intestinal symptoms ascribed to Blastocystis, for which the patient was prescribed metronidazole. We know that Blastocystis is only rarely eradicated by metronidazole alone, and indeed, the article does not provide data on post-treatment stool examination to see whether Blastocystis was still there. I think there is a chance that Blastocystis was an incidental finding and that intestinal symptoms in this case were due to Schistosoma. Given our recent data and improved diagnostic techniques, Blastocystis will more often now than ever become an incidental finding on routine analysis of faecal samples.

There is a paper by Fletcher and colleagues coming out in Journal of Public Health Research studying the prevalence and geographical distribution of enteric protozoan infections in Sydney, Australia, which I haven't had a chance to study in detail. I just want to emphasize that this study found Blastocystis prevalence to be increasing by age, a finding adding support to accumulating data suggesting that Blastocystis is more common in adults than in children, which is interesting from a clinical, epidemiological, and ecological point of view.

Hope to be able to address an interesting and brand new paper on Blastocystis treatment in Faculty of 1000 very soon. 

Happy Halloween!


Fletcher S, Caprarelli G, Merif J, Andresen D, Hal SV, Stark D, & Ellis J (2014). Epidemiology and geographical distribution of enteric protozoan infections in Sydney, Australia. Journal of Public Health Research, 3 (2) PMID: 25343139

Nagel R, Bielefeldt-Ohmann H, & Traub R (2014). Clinical pilot study: efficacy of triple antibiotic therapy in Blastocystis positive irritable bowel syndrome patients. Gut Pathogens, 6 PMID: 25349629

Nowack EC, & Melkonian M (2010). Endosymbiotic associations within protists. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 365 (1541), 699-712 PMID: 20124339

Prodeus TV, Zelia OP, Khlebnikova TA, & Pikul' DA (2014). [Extraenteric infection caused by Blastocystis spp. in a female patient with liver abscess]. Meditsinskaia Parazitologiia i Parazitarnye Bolezni (2), 6-9 PMID: 25296418

Young CR & Yeo FE (In Press). Blastocystis and Schistosomiasis coinfection in a patient with chronic kidney disease. Case Reports in Medicine