Blastocystis Research Foundation

Since Blastocystis occurs in individuals with and without symptoms, the clinical community has a strong interest in differences that exist between those two types of infections.  Researchers comparing Blastocystis isolates from symptomatic and asymptomatic individuals report that isolates from symptomatic individuals exhibited a higher degree of production of a Capase-like proteases, chemicals which cleave other proteins and are involved in the process of programmed cell death.  Most interestingly, three different genetically distinct subtypes of Blastocystis exhibited this behavior, with subtypes 1, 3, and 5 from symptomatic individuals showing different behavior from subtypes 1, 3, and 5 from asymptomatic individuals.  The full study has been published in BMC Parasites and Vectors.

Researchers studying patients from several large University hospitals in Iran report that Blastocystis infection is found more frequently in individuals with higher serum iron counts, and is also associated with higher levels of C-reactive protein, occult blood, and erythrocyte sedimentation levels.  Overall, 97600 stool examinations were done in 4 university hospitals. Parasites were observed in 46,200 specimens.  Of these cases, 6851 cases had complete blood work information along with only B. hominis infection. In the control group, 3615 subjects without parasite infestation were included. Erythrocyte sedimentation rate level was significantly higher in cases with B. hominis infection (p < 0.05). C-reactive protein level was positive in 1.46% of cases and 0.5% of controls, which was statistically significant (p < 0.05). Frequency of serum iron < 120 was significantly higher in cases with B. hominis infection compared to controls. Occult blood was positive in 0.93% of cases and in none of the controls (p < 0.05).  For more information, refer to the paper from Pzgelad Gastroenterology.

Researchers from Sydney and New South Wales Australia have published a summary of existing research on Blastocystis pathogenicity along with a summary of treatment options.  For more information, refer to the paper published in Gut Pathogens.

Researchers from the University of Singapore, working with several strains of Blastocystis sp. subtype 7, report that differences exist between the ability of strains to adhere to intestinal colonic cells.  These differences appear to relate to the ability of the cells to increase intestinal permeability, one of the mechanisms that can produce diarrhea in symptomatic individuals.  The study suggested that metronidazole resistance was associated with a fitness cost, since cells made resistant to Blastocystis exhibited a lower degree of adhesion.  For more information, refer to the paper in PLOS Neglected Pathogens.

Researchers working with human enterocytes, columnal cells found in the intestine, report that exposure to Blastocystis sp. subtype 7 significantly reduces intestinal permeability, a property common to many intestinal pathogens, and one cause of the symptom of diarrhea.  Exposure to Blastocystis sp. subtype 7 also produced a statistically significant increase in programmed cell death in enterocytes.  Similar exposure to Blastocystis sp. subype 4 did not produce these effects, suggesting the existence of a strain-dependent effect.  For additional information, please refer to the paper from Biomed Research International.

Researchers at the University of Malaysia report that experimental Blastocystis infection reduces the rate of weight gain in Wistar rates significantly.  Additionally, Blastocystis antigen was found to reduce the proliferation of peripheral monocytes in vitro, which the researchers identified as an immuno-suppressant property of the antigen.  Wistar rates who were stressed showed a significant impairment in their response to Blastocystis infection, with higher cyst counts found in stool samples, higher concentrations of some markers which gauge immune response, but inhibition of white blood cell activity. For more information, see the paper from PLOS-One.

Researchers from Rio de Janero report the identification of Blastocystis infection in splenic cysts from an adult 22-year old female case report, with no co-morbidities such as HIV infection or cancer identified.  The patient presented with recurrent complaints of abdominal pain.  Symptoms resolved following surgery, and Blastocystis presence was confirmed through microscopy and PCR sequencing, which identified the organism as Blastocystis sp. subtype 3.  For additional information, refer to the article from BMC Parasites and Vectors.

Researchers from the University of Malaysia studying patients with colorectal cancer report a much higher prevalence of Blastocystis infection in those patients compared to normal controls.   The study included 204 patients with colorectal cancer, and 221 normal controls, the Blastocystis infection found at a rate of Blastocystis infection of 21% in colorectal cancer patients, vs. 9.95% in normal controls.  The study also reported that the sensitivity of detection provided by culturing stool samples was significantly lower than that provided by colonic washouts.  The full text of the paper is available from BMC Parasites and Vectors.

The 2015 International Blastocystis Symposium was a success, with researchers attending from over a half dozen countries.  Stay tuned for a complete report upcoming on this event.

We are completing evaluation of the travel grant applications to the Blastocystis 2015 conference in Ankara.  If you are a researcher and interested in applying, be sure to submit your application by Tuesday, April 7!  Contact director a t bhomcenter.org for an application.