Characterization of Coxiella burnetii strains from ruminants in a Galleria mellonella host-based model

Coxiella burnetii is a small Gram-negative intracellular bacterium and is the causative agent of Q fever, which is a zoonotic disease with a worldwide distribution. Domesticated ruminants are the main reservoir of the disease, but the bacterium is able to infect a wide range of hosts, including humans, arthropods and invertebrates. Virulence studies of Coxiella strains usually require a suitable animal model. However, mammalian models are costly and are associated with many ethical constraints. An alternative infection model using Galleria mellonella has been used to study the virulence of several bacterial as well as fungal pathogens. Moreover, the G. mellonella larvae model has been used to identify virulence genes using phase II C. burnetii strain Nine Mile mutants. In our study we describe its use for the characterization of C. burnetii strains isolated from ruminants.