title: In Vitro Antimicrobial Susceptibility Patterns of Blastocystis.
abstract: Blastocystis is the most common human enteric protist with controversial clinical significance. Metronidazole is considered a first-line treatment for Blastocystis infection; however, there has been increasing evidence for the lack of efficacy of this treatment. Treatment failure has been reported in several clinical cases, and recent in vitro studies have suggested the occurrence of metronidazole-resistant strains. In this study, we tested 12 Blastocystis isolates from 4 common Blastocystis subtypes (ST1, ST3, ST4, and ST8) against 12 commonly used antimicrobials (metronidazole, paromomycin, ornidazole, albendazole, ivermectin, trimethoprim-sulfamethoxazole [TMP-SMX], furazolidone, nitazoxanide, secnidazole, fluconazole, nystatin, and itraconazole) at 10 different concentrations in vitro. It was found that each subtype showed little sensitivity to the commonly used metronidazole, paromomycin, and triple therapy (furazolidone, nitazoxanide, and secnidazole). This study highlights the efficacy of other potential drug treatments, including trimethoprim-sulfamethoxazole and ivermectin, and suggests that current treatment regimens be revised.
authors.affiliation: Department of Microbiology, St. Vincent's Hospital, Darlinghurst, NSW, Australia School of Medical and Molecular Biosciences, University of Technology, Sydney, Ultimo, NSW, Australia tamalee.roberts@svha.org.au.
authors.forename: Tamalee
authors.initials: T
authors.lastname: Roberts
authors.affiliation: Faculty Of Science, University of Technology, Sydney, Ultimo, NSW, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bush
authors.affiliation: School of Medical and Molecular Biosciences, University of Technology, Sydney, Ultimo, NSW, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Ellis
authors.affiliation: Department of Microbiology, St. Vincent's Hospital, Darlinghurst, NSW, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Harkness
authors.affiliation: Department of Microbiology, St. Vincent's Hospital, Darlinghurst, NSW, Australia.
authors.forename: Damien
authors.initials: D
authors.lastname: Stark
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D016844:Blastocystis / Q000187:drug effects* / Q000302:isolation & purification; D016776:Blastocystis Infections / Q000188:drug therapy; D005243:Feces / Q000382:microbiology; D006801:Humans
chemical_list: D000890:Anti-Infective Agents; D000981:Antiprotozoal Agents