Antibiotic susceptibility of Neochlamydia hartmanellae and Parachlamydia acanthamoebae in amoebae.
Parachlamydia acanthamoebae and Neochlamydia hartmanellae are Chlamydia-related bacteria naturally infecting free-living amoebae. These strict intracellular bacteria might represent emerging pathogens. Recent studies report an association with lower respiratory tract infections, especially with pneumonia where they have been identified as a potential causative agent in 1-2% of cases. In this study, we defined the antibiotic susceptibility of N. hartmanellae, two strains of P. acanthamoebae and two yet unclassified Parachlamydiaceae strains using a quantitative approach. We confirmed the results obtained earlier for P. acanthamoebae strain Bn9 in an observational study. Macrolides (MICs < 0.06-0.5 μg/ml), rifampicin (MICs 0.25-2) and doxycycline (2-4 μg/ml) were active against P. acanthamoebae strains and Neochlamydia. All strains were resistant to amoxicillin, ceftriaxone and imipenem (MIC ≥32 μg/ml). Similarly to other Chlamydia-related bacteria, all investigated Parachlamydiaceae were resistant to quinolones (MICs ≥ 16 μg/ml). Therefore, we recommend a treatment with macrolides for Parachlamydia-associated pneumonia.
Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland; Materno-fetal and Obstetrics Research Unit, Department of Obstetrics and Gynecology, Maternity, University Hospital, Lausanne, Switzerland.
Manon
M
Vouga
Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
Houria
H
Diabi
Emerging Infectious and Tropical Diseases Research Unit (URMITE), Medicine Faculty, Aix-Marseille University, Marseille, France.
Areen
A
Boulos
Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
David
D
Baud
Emerging Infectious and Tropical Diseases Research Unit (URMITE), Medicine Faculty, Aix-Marseille University, Marseille, France.
Didier
D
Raoult
Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland. Electronic address: gilbert.greub@chuv.ch.
Gilbert
G
Greub
D000656:Amoeba / Q000382:microbiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002695:Chlamydiales / Q000187:drug effects* / Q000472:pathogenicity*; D024901:Drug Resistance, Multiple, Bacterial / Q000502:physiology*; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D018942:Macrolides / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D011014:Pneumonia / Q000382:microbiology; D047090:beta-Lactams / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D018942:Macrolides; D047090:beta-Lactams
Antibiotic; Chlamydia; Intracellular bacteria; Parachlamydiaceae; Pneumonia