Antibiotic susceptibility of Estrella lausannensis, a potential emerging pathogen

• Published in: Microbes and infection 2014-09, Vol.16 (9), p.746-754
• Main Authors: de Barsy, Marie, Bottinelli, Lavinia, Greub, Gilbert
• Format: Article
• Language: English
• Subjects: Acanthamoeba castellanii; Animals; Anti-Bacterial Agents - pharmacology; Antibiotic susceptibility; Azithromycin - pharmacology; beta-Lactams - pharmacology; Cell culture; Cercopithecus aethiops; Child, Preschool; Chlamydia-like organism; Chlamydiae; Chlamydiales - classification; Chlamydiales - drug effects; Chlamydiales - genetics; Coculture Techniques; Drug Resistance, Bacterial; Female; Fluoroquinolones - pharmacology; Genes, rRNA; Humans; Vero Cells
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2014.08.003

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.