Personal Post-Conference Thoughts on Future Blastocystis Research

I'm still on a high after the 3rd Int'l Blastocystis Conference! The Scientific Committee is in the process of putting together a TrendsTalk paper for Trends in Parasitology to provide a brief summary of the different topics presented at the conference, including some important updates.

I personally think Blastocystis research has come a long way since I entered the field back in 2004, but I would like to call for more cross-disciplinary approaches to studying the parasite.

In particular, we need to stimulate a research interest in bioinformaticians, vets, food microbiologists, and gastroenterologists.

The bioinformatics people should help us analyze NGS data (shotgun, metabarcoding) and provide some robust and  guidelines for cut-offs for e.g. Blastocystis positivity and negativity in NGS data.

Vets should be interested in studying the differences in Blastocystis colonization across different animal populations and find out what drives colonization and the impact is has on the host and host gut microbiota. Studying the relationships of these microbes in animals can help us understand these relationships in humans. Vets should help us find out why Blastocystis is so common in ruminants and so rare in carnivores.

To this end, food microbiologists should take an interest to study associations and interactions between Blastocystis, the gut microbiota and the host. Including metabolomics. Diet as a driver of colonization should be investigated.

Finally, gastroenterologists should take an interest in Blastocystis to identify its positive or negative association to various GI diseases (IBS, IBD, microscopic colitis, coeliac disease, diverticulosis, colon cancer, etc, etc.)

We should take advantage of the fact that Blastocystis is one of the few intestinal parasites that can easily be cultured, which means that cells can be used for in vivo and in vitro experiments. Protocols should be developed for encystment, and cyst production on a larger scale should be enabled, since cysts can be used for oral administration. 

The current shift in paradigm that reflects the recognition of Blastocystis as marker of intestinal eubiosis could be supported and expanded by increasing the involvement of these types of professions.

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