title: Subtype distribution of Blastocystis isolates in Sebha, Libya.
abstract: BACKGROUND
  Blastocystis is a genetically diverse and a common intestinal parasite of humans with a controversial pathogenic potential. This study was carried out to identify the Blastocystis subtypes and their association with demographic and socioeconomic factors among outpatients living in Sebha city, Libya.
  
  
  RESULTS
  Blastocystis in stool samples were cultured followed by isolation, PCR amplification of a partial SSU rDNA gene, cloning, and sequencing. The DNA sequences of isolated clones showed 98.3% to 100% identity with the reference Blastocystis isolates from the Genbank. Multiple sequence alignment showed polymorphism from one to seven base substitution and/or insertion/deletion in several groups of non-identical nucleotides clones. Phylogenetic analysis revealed three assemblage subtypes (ST) with ST1 as the most prevalent (51.1%) followed by ST2 (24.4%), ST3 (17.8%) and mixed infections of two concurrent subtypes (6.7%).
  ST1 infection was significantly associated with female (P = 0.009) and low educational level (P = 0.034). ST2 was also significantly associated with low educational level (P= 0.008) and ST3 with diarrhoea (P = 0.008).
  
  
  CONCLUSIONS
  Phylogenetic analysis of Libyan Blastocystis isolates identified three different subtypes; with ST1 being the predominant subtype and its infection was significantly associated with female gender and low educational level. More extensive studies are needed in order to relate each Blastocystis subtype with clinical symptoms and potential transmission sources in this community.
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; Department of Medical Laboratory Sciences, Faculty of Engineering and Technology, University of Sebha, Sebha, Libya.
authors.forename: Awatif M
authors.initials: AM
authors.lastname: Abdulsalam
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Init
authors.initials: I
authors.lastname: Ithoi
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
authors.forename: Hesham M
authors.initials: HM
authors.lastname: Al-Mekhlafi
authors.affiliation: Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
authors.forename: Abdulsalam M
authors.initials: AM
authors.lastname: Al-Mekhlafi
authors.affiliation: Department of Biology, Faculty of Natural and Applied Sciences, Umaru Musa Yar'adua University, Katsina, Nigeria.
authors.forename: Abdulhamid
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Johari
authors.initials: J
authors.lastname: Surin
mesh_terms: D001483:Base Sequence; D016844:Blastocystis / Q000235:genetics* / Q000472:pathogenicity; D016776:Blastocystis Infections / Q000453:epidemiology*; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005243:Feces / Q000469:parasitology; D006801:Humans; D008002:Libya / Q000453:epidemiology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012959:Socioeconomic Factors; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal