title: Antibiotic susceptibility of Estrella lausannensis, a potential emerging pathogen.
abstract: Estrella lausannensis is a new Chlamydia-related bacterium, belonging to the Criblamydiaceae family. As suggested by its species name, this bacterium harbors a peculiar star shape. E. lausannensis is able to infect a wide range of amoebal, fish and mammalian cell lines. Moreover, seroprevalence of 2.9% was reported in children and in women with tubal pathology, showing that humans are commonly exposed to this recently discovered strict intracellular bacteria considered as a potential pathogen. Antibiotic susceptibility was determined using two approaches: qPCR and cellular mortality assay. Antibiotics classically used against intracellular bacteria were tested, including β-lactams, fluoroquinolones, cyclines and macrolides. We showed that E. lausannensis is resistant to β-lactams and fluoroquinolones, and sensitive to cyclines. Interestingly, E. lausannensis is slightly resistant to azithromycin with a MIC of 2 μg/ml, which is 10 fold higher compared to Waddlia chondrophila and Parachlamydia acanthamoebae MIC's. A single A2059C mutation in 23S rRNA gene could be responsible for this unexpected resistance.
authors.affiliation: Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: de Barsy
authors.affiliation: Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
authors.forename: Lavinia
authors.initials: L
authors.lastname: Bottinelli
authors.affiliation: Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland. Electronic address: gilbert.greub@chuv.ch.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
mesh_terms: D048248:Acanthamoeba castellanii; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D002675:Child, Preschool; D002695:Chlamydiales / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D002522:Chlorocebus aethiops; D018920:Coculture Techniques; D024881:Drug Resistance, Bacterial; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology; D020459:Genes, rRNA; D006801:Humans; D014709:Vero Cells; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D047090:beta-Lactams; D017963:Azithromycin
keywords: Antibiotic susceptibility; Cell culture; Chlamydia-like organism; Chlamydiae