Intra-haemocoelic Injection for PK/PD Assessment of Antifungal Agents Against Candida Auris

DATE: September 2025
Attikon University General Hospital | National and Kapodistrian University of Athens | Vasiliki Kroustali, PhD student & researcher 

The syringes will be used for inoculation of Candida auris isolates from different clades in Galleria mellonella larvae (greater wax moth) and for subsequent antifungal treatments. In our infection model, both Candida cells and antifungal drugs require precise intra-haemocoelic injection through the prolegs. These injections form the foundation of our pharmacokinetic/pharmacodynamic (PK/PD) studies, which aim to improve treatment strategies against this multidrug-resistant “superbug.” 

C. auris infections have now been reported on all major continents, with candidaemia mortality estimated at nearly 50%. This pathogen is notorious for its nosocomial spread, persistent colonization, and emerging resistance across major categories of antifungal drugs. As treatment remains highly challenging, there is an urgent need for PK/PD studies that assess the efficacy of different antifungals and doses, ultimately defining PK/PD cut-offs for each drug across clades and susceptibility profiles. 

To address this gap, we have established an infection model using Galleria mellonella larvae. This non-vertebrate model has been used previously to study antifungal efficacy and Candida virulence, while offering multiple pharmacodynamic endpoints such as CFU counts, survival analysis, and overall health scoring. Importantly, it provides a cost-effective, ethically advantageous alternative to mammalian models and aligns with the 3Rs principle — reduction, replacement, and refinement of vertebrate animal use in scientific research. 

Our model requires extremely high precision and reproducibility, as each experiment involves multiple injections per larva (initial inoculation with C. auris isolates followed by sequential antifungal dosing). The delicacy of the organism makes the accuracy of injections critical for valid results. To ensure scientific rigor, we repeat all experimental conditions under carefully standardized parameters, enabling robust and reproducible datasets. Based on our experience, Hamilton syringes will both optimize our model and minimize waste. 

Receiving the Hamilton Syringe Grant will bring us closer to establishing PK/PD-guided treatment strategies against multidrug-resistant C. auris by generating high-quality, reproducible data from an innovative in vivo model.