Infection of Zebrafish Larvae with <em>Aspergillus</em> Spores for Analysis of Host-Pathogen Interactions

Abstract

Invasive aspergillosis (IA) is one of the most common fungal infections among immunocompromised individuals. Despite the availability of antifungal drugs, IA can cause >50% mortality in infected immunocompromised patients. It is crucial to determine both host and pathogen factors that contribute to infection susceptibility and low survival rates in infected patients in order to develop novel therapeutics. Innate immune responses play a pivotal role in recognition and clearance of Aspergillus spores, though little is known about the exact cellular and molecular mechanisms. Reliable models are required to investigate detailed mechanistic interactions between the host and pathogen. The optical clarity and genetic tractability of zebrafish larvae make them an intriguing model to study host-pathogen interactions of multiple human bacterial and fungal infections in a live and intact host. This protocol describes a larval zebrafish Aspergillus infection model. First, Aspergillus spores are isolated and injected into the zebrafish hindbrain ventricle via microinjection. Then, chemical inhibitors such as immunosuppressive drugs are added directly to the larval water. Two methods to monitor the infection in injected larvae are described, including the 1) homogenization of larvae for colony forming unit (CFU) enumeration and 2) a repeated, daily live imaging setup. Overall, these techniques can be used to mechanistically analyze the progression of Aspergillus infection in vivo and can be applied to different host backgrounds and Aspergillus strains to interrogate host-pathogen interactions.

Comparison of quality/quantity mNGS and usual mNGS for pathogen detection in suspected pulmonary infections

“…This may have been due to the different types of enrolled patients or the relatively small number of enrolled patients. Almost all enrolled patients (94.4%) were immunocompromised; they were much more susceptible to infection, and the pathogens may be uncommon and different from those of immunocompetent individuals ( Thrikawala and Rosowski, 2020 ). Both QmNGS (72%) and UmNGS (76%) showed high sensitivity, similar to the results of a previous study ( Huang et al., 2020 ).…”