Development of Galleria mellonella as an alternative infection model for the Burkholderia cepacia complex.

Burkholderia is an important bacterial genus with a complex taxonomy that contains species of both ecological and pathogenic importance, including nine closely related species collectively termed the Burkholderia cepacia complex (BCC). In order to more thoroughly investigate the virulence of this bacterial complex of microorganisms, alternative infection models would be useful. To this end, we have adapted and developed the use of the Galleria mellonella wax moth larvae as a host for examining BCC infections. The experimental conditions affecting the BCC killing of the "wax worm" were optimized. BCC virulence levels were determined using 50% lethal doses, and differences were observed between both species and strains of the BCC. The BCC pathogenicity trends obtained compare favorably with results acquired using other published alternative infection models, as well as mammalian infection models. In addition, BCC killing activity was determined by directly measuring relative bacterial loads in three different BCC strains, thus demonstrating innate differences in BCC strain virulence. Finally, genetically mutated BCC strains were compared to a wild-type BCC strain in order to show concomitant reduction of BCC virulence and increased wax worm survival. For experimentation examining the virulent properties of the BCC, the wax worm has proven to be a useful alternative infection model.