title: Tigecycline inhibits proliferation of Acanthamoeba castellanii.
abstract: Acanthamoeba is an opportunistic protozoan parasite responsible for different diseases in humans, such as granulomatous amoebic encephalitis and amoebic keratitis. Tigecycline, a third-generation tetracycline antibiotic, has potential activity to treat most of the antibiotic resistant bacterial infections. The effects of tigecycline in eukaryotic cells as well as parasites are less well studied. In the present study, we tested the effects of tigecycline on trophozoites of Acanthamoeba castellanii. The inhibitory effect of tigecycline on Acanthamoeba was determined by resazurin reduction and trypan blue exclusion assays. We found that tigecycline significantly inhibited the growth of Acanthamoeba (46.4 % inhibition at the concentration of 100 μM) without affecting cell viability and induction of encystation, whereas other tetracycline groups of antibiotics such as tetracycline and doxycycline showed no inhibitory effects. Furthermore, tigecycline decreased cellular adenosine triphosphate (ATP) level by 26 % than the control and increased mitochondrial mass, suggesting mitochondrial dysfunction in tigecycline-treated cells. These findings suggest that mitochondrial dysfunction with decreased ATP production might play an important mechanism of tigecycline in suppression of Acanthamoeba proliferation.
authors.affiliation: Department of Microbiology, Keimyung University School of Medicine, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 704-701, Republic of Korea.
authors.forename: Bijay Kumar
authors.initials: BK
authors.lastname: Jha
authors.forename: Incheol
authors.initials: I
authors.lastname: Seo
authors.forename: Hyun-Hee
authors.initials: HH
authors.lastname: Kong
authors.forename: Seong-Il
authors.initials: SI
authors.lastname: Suh
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Suh
authors.forename: Won-Ki
authors.initials: WK
authors.lastname: Baek
mesh_terms: D000048:Acanthamoeba / Q000187:drug effects; D048248:Acanthamoeba castellanii / Q000187:drug effects*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004660:Encephalitis; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D010078:Oxazines; D000078304:Tigecycline; D053058:Trophozoites / Q000187:drug effects; D014966:Xanthenes
chemical_list: D000900:Anti-Bacterial Agents; D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D000078304:Tigecycline; D008911:Minocycline