title: Epidemiological and clinical profile of adult patients with Blastocystis sp. infection in Barcelona, Spain.
abstract: Blastocystis spp. are among the most frequently observed intestinal parasites in humans. Despite the discovery of Blastocystis approximately 100 years ago, limited information is available regarding its pathogenesis, genetic diversity, and available treatment options. The aim of this study was to describe the epidemiological and clinical characteristics of patients with Blastocystis sp. infections diagnosed at Vall d'Hebron University Hospital (Barcelona, Spain).
  
  
  
  A retrospective observational study was performed which included all adult patients who attended Vall d'Hebron University Hospital from February 2009 to March 2014 that had Blastocystis sp. detected in their stool.
  
  
  
  Four hundred eighteen patients were included, the median age was 36 (18-86) years and 236 (56.5 %) were men. Regarding patient symptoms, 234 (56 %) patients were completely asymptomatic, 92 (22 %) patients had symptoms, and 92 (22 %) patients had symptoms that could be attributed to other causes. Of the 92 patients with symptoms not attributable to other etiologies except for Blastocystis infection, the most frequent symptoms were diarrhea (61 patients, 66.3 %) and abdominal pain (34 patients, 37 %). Additionally, nine (9.8 %) patients had cutaneous manifestations. Thirty-one (7.4 %) patients received specific treatment for Blastocystis infection. The clinical response of treated patients was varied. Five patients experienced complete resolution of symptoms, 12 patients reported improvement of clinical symptoms, eight patients described no clinical improvement, and information was unavailable for six patients.
  
  
  
  Blastocystis infection was detected in 418 patients, most of them foreign-born. Although the vast majority of patients were asymptomatic, 22 % of patients had gastrointestinal symptoms or cutaneous manifestations in the absence of other causes. Despite the scarce information available, given the safety of antiparasitic treatment, and the percentage of patients who experienced resolution or improvement of symptoms, treatment should be considered in patients with chronic symptoms.
authors.affiliation: Department of Infectious Diseases, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, PROSICS Barcelona, Barcelona, Spain. fmsalvad@vhebron.net.
authors.forename: Fernando
authors.initials: F
authors.lastname: Salvador
authors.affiliation: Department of Microbiology, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Sulleiro
authors.affiliation: Department of Infectious Diseases, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, PROSICS Barcelona, Barcelona, Spain.
authors.forename: Adrián
authors.initials: A
authors.lastname: Sánchez-Montalvá
authors.affiliation: Gastroenterology Department, Vall d' Hebron Research Institute, Digestive Diseases Research Unit, Vall d'Hebron University Hospital, Barcelona, Spain.|Department of Medicine, Universitat Autònoma de Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Barcelona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Alonso
authors.affiliation: Gastroenterology Department, Vall d' Hebron Research Institute, Digestive Diseases Research Unit, Vall d'Hebron University Hospital, Barcelona, Spain.|Department of Medicine, Universitat Autònoma de Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Santos
authors.affiliation: Instituto de Salud Carlos III, National Centre of Microbiology, Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Fuentes
authors.affiliation: Department of Infectious Diseases, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, PROSICS Barcelona, Barcelona, Spain.
authors.forename: Israel
authors.initials: I
authors.lastname: Molina
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D058345:Asymptomatic Infections / Q000453:epidemiology*; D016844:Blastocystis / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D016776:Blastocystis Infections / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology*; D003967:Diarrhea / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000469:parasitology; D006801:Humans; D007422:Intestines / Q000469:parasitology; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use; D008875:Middle Aged; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000981:Antiprotozoal Agents; D008795:Metronidazole
keywords: Blastocystis; Gastrointestinal symptoms; Intestinal protozoa; Metronidazole