Gene expression in Lucilia sericata (Diptera: Calliphoridae) larvae exposed to Pseudomonas aeruginosa and Acinetobacter baumannii identifies shared and microbe‐specific induction of immune genes

Antibiotic resistance is a continuing challenge in medicine. There are various strategies for expanding antibiotic therapeutic repertoires, including the use of blow flies. Their larvae exhibit strong antibiotic and antibiofilm properties that alter microbiome communities. One species, Lucilia sericata, is used to treat problematic wounds due to its debridement capabilities and its excretions and secretions that kill some pathogenic bacteria. There is much to be learned about how L. sericata interacts with microbiomes at the molecular level. To address this deficiency, gene expression was assessed after feeding exposure (1 h or 4 h) to two clinically problematic pathogens: Pseudomonas aeruginosa and Acinetobacter baumannii. The results identified immunity‐related genes that were differentially expressed when exposed to these pathogens, as well as non‐immune genes possibly involved in gut responses to bacterial infection. There was a greater response to P. aeruginosa that increased over time, while few genes responded to A. baumannii exposure, and expression was not time‐dependent. The response to feeding on pathogens indicates a few common responses and features distinct to each pathogen, which is useful in improving the wound debridement therapy and helps to develop biomimetic alternatives. Gene expression response of Lucilia sericata to feeding on two clinically important bacteria: Mostly an AMP response, including AMP‐related effector Fewer genes respond that when flies are inoculated via needle Major differences in response to exposure to different bacteria Largely an IMD pathway response, with IM18 expression implying a role for Toll signaling Ecdysone, Insulin/TOR, and Salvador/Hippo/Warts pathways involved in one response Gut‐expressed genes imply an important role for differences in immune response