Genomic Analysis of Blastocystis hominis Strains Isolated from Two Long-Term Health Care Facilities

Abstract

The genotype Blastocystis hominis is highly polymorphic. Therefore, a genetic marker would be a powerful tool for the identification or classification of B. hominis subtypes and could be used as a means to resolve the transmission route or origin of the parasite. To this end, 32 B. hominis isolates were collected from patients and/or staff members of two long-term health care facilities (facilities A and B), and these organisms were subjected to genotype analysis based on diagnostic PCR primers and restriction fragment length polymorphism (RFLP) of small subunit rRNA gene (rDNA). Based on PCR amplification using diagnostic primers which were developed from randomly amplified polymorphic DNA analysis of known strains of B. hominis, the 32 isolates of B. hominis were classified into three different subtypes. Thirty isolates, including twenty-four that were isolated from patients and a staff member, from facility A and all isolates isolated from six patients from facility B showed the same genotype. Two of six patients of facility B had been transferred from facility A, and these two patients also had the same-genotype B. hominis that corresponded to 24 isolates from facility A. This genotype strain may have been transmitted by these two patients from facility A to facility B, suggesting human-to-human transmission. In contrast, 2 of 26 isolates from facility A showed distinct genotypes, suggesting that the colonization by these two isolates is attributable to another infectious route. These different subtypes were subjected to RFLP analysis, and the RFLP profiles were correlated with the results obtained by diagnostic PCR primers. This study presents the first molecular evidence of possible human-to-human B. hominisinfection between and/or among two small communities.

Ultrastructural and Phylogenetic Studies on Blastocystis Isolates from Cockroaches

“…Amplification and sequencing of SSU rDNA. A pair of sense (SR1F) and anti-sense (SR1R) primers were primarily used for amplification of almost the entire length of the SSU rRNA genes (Yoshikawa et al 2000). However, the amplicon showed a weak band in an agarose gel.…”

“…Therefore, various molecular approaches, such as randomly amplified polymorphic DNA, sequence-tagged site primer analyses, and fingerprinting of the small subunit (SSU) rRNA genes, have been used to analyze Blastocystis isolates from humans and non-human hosts. These studies revealed that the genus Blastocystis exhibits extensive genetic diversity (Abe, Wu, and Yoshikawa 2003a;Abe, Wu, and Yoshikawa 2003b;Abe, Wu, and Yoshikawa 2003c;Clark 1997;Hoevers et al 2000;Yoshikawa, Abe, and Wu 2004a;Yoshikawa et al 1996Yoshikawa et al , 1998Yoshikawa et al , 2000Yoshikawa et al , 2003Yoshikawa et al , 2004c. Molecular phylogenetic studies using gene sequences of the SSU rRNA or elongation factor-1 a (EF-1a) have also been performed to infer relationship among Blastocystis isolates from birds, reptiles, amphibians, and a variety of mammals, including humans (Arisue, Hashimoto, and Yoshikawa 2003;Ho et al 2000;Noël et al 2003;Yoshikawa et al 2004b).…”

Blastocystis: unravelling potential risk factors and clinical significance of a common but neglected parasite

“…Blastocystis is a common, single-celled, enteric endosymbiont of man and animals [1][2][3][4][5]. Often, Blastocystis is the only potential disease-causing agent found in faecal specimens from patients with diarrhoea or other gastrointestinal (GI) symptoms ; however, Blastocystis is also common in asymptomatic individuals [6][7][8][9][10][11]. For eradication of Blastocystis infections, metronidazole is considered the first-line therapy [1,12].…”

“…So far, studies seeking to unveil subtype-specific pathogenicity have produced conflicting conclusions [6][7][8][9][10][11]16]. However, such studies have not consistently included testing for other enteropathogens, e.g.…”

Systemic Lupus Erythematosus and Irritable Bowel Syndrome: Is Blastocystis Hominis the Missing Piece of the Puzzle

“…Genomic DNA of B. hominis was extracted by using DNAzol reagent (Gibco BRL/Life Technologies, Inc., Grand Island, N.Y.) according the manufacturer's instructions. PCR technique was performed as previously described by Yoshikawa et al, 2000 (16) and Blastocystis sp. subtypes were identified using classification proposed by Stensvold et al, in 2007, in which Blastocystis sp.…”