Unexpected Presence of Blastocystis Subtype 1-3 DNA in Human Vaginal and Sperm Samples Coinfected with Trichomonas vaginalis

There have been few reports on extra-enteric infections by <i>Blastocystis</i> STs and none have been molecularly identified in samples from human reproductive organs. We report for the first time the identification of 3 different subtypes of <i>Blastocystis</i> (ST1-3) in vaginal and sperm samples, from patients infected with <i>Trichomonas vaginalis</i>. <i>Blastocystis</i> STs were identified by PCR-sequencing and by phylogenetic inferences using 28 vaginal swab samples and 7 sperm samples from patients trichomoniasis. <i>Blastocystis</i> STs were identified in 6 of 28 vaginal swabs (21.4%) and in 3 of 7 sperm samples (42.8%). In both biological samples, STs 1-3 were found; one vaginal sample showed subtype co-infection with ST1 and ST3. High genetic variation was observed in the sequences obtained and no specific clustering in the phylogenetic trees was detected. Most of the haplotypes identified were placed far from the main dispersal centers. Our finding suggested that incorrect cleaning of the genital area or a contamination by combination of anal and vaginal intercourse.

Molecular analysis of Blastocystis sp. and its subtypes from treated wastewater routinely used for irrigation of vegetable farmlands in Iran

Treated wastewater samples were collected, filtered using sterile 47-mm cellulose nitrate membrane and DNA extracted from the filtered materials. The presence of Blastocystis sp. was confirmed via polymerase chain reaction (PCR) targeting the SSU rRNA gene of Blastocystis sp. in 5/12 of samples. Based on the subtype analysis after sequencing, 2, 2 and 1 of ST2, ST6 and ST8 were detected among the isolates, respectively. Furthermore, both ST6s were allele 139, alleles 11 and 138 were identified in ST2 and the only ST8 was allele 95. The phylogenetic tree showed that one of ST2 was clustered together with those ST2 that were already reported from humans and animals. The presence of Blastocystis sp. in treated wastewater can indicate the potential role of this type of water for irrigation in the transmission of pathogenic microorganisms to downstream farmlands.

Blastocystis elongation factor-1alpha: genomic organization, taxonomy and phylogenetic relationships

The elongation factor-1 alpha (EF-1alpha) is a highly conserved ubiquitous protein that is involved in translation and is desirable for use in phylogenetic studies on Blastocystis, an enigmatic intestinal parasite with a contentious taxonomic position. In the present study, a PCR product (BEalpha) that codes for a major part of the coding region of the EF-lalpha protein was amplified. Genome walking experiments together with cloning were implemented to elucidate the 5' and 3' ends of the EF-1alpha gene of the human isolate, Blastocystis hominis C. The genomic organization and the potential transcription factor binding sites of the 5' end of B. hominis C EF-1alpha were identified. A comparative study on the deduced amino acid sequences of BEalpha of 13 Blastocystis isolates from various hosts was done to evaluate the phylogenetic relationship among the species. A phylogenetic reconstruction analysis with other eukaryotic EF-1alpha sequences was carried out to trace the phylogenetic position of Blastocystis among eukaryotic organisms.

Blastocystis hominis in inflammatory bowel disease

We retrospectively examined the hospital course of 12 patients with exacerbated inflammatory bowel disease (IBD), who also had stool specimens positive for Blastocystis hominis to determine the effect of B. hominis on their disease. Bloody bowel movements were common with ulcerative colitis patients and watery diarrhea with Crohn's disease; other findings included abdominal pain, fever, nausea, and vomiting. All patients responded favorably to medical therapy. Three responded to treatment with corticosteroids alone, and one patient improved with bowel rest without medications. Five patients failed to improve on metronidazole; four of them responded to a subsequent course of corticosteroids, whereas the fifth patient became asymptomatic after erythromycin treatment for concomitant Campylobacter jejuni. Finally, three patients responded to treatment with metronidazole alone, which is known to eradicate B. hominis but may also have a beneficial effect on IBD. In no case did corticosteroid treatment worsen the condition. Our findings indicate that B. hominis is not a significant pathogen in IBD and treatment must be directed toward the underlying illness.