Glucose dependent resistance associated with intestinal microbiota facilitate teleost to survive bacterial infection

Host microbiota interaction affects the metabolism and immune regulation in the host. To explore the disease resistance mechanism and the host-microbiota interaction details, the intestinal transcriptome and microbiome of moribund and surviving fish infected with Aerompnas hydrophila as well as healthy controls were cross-analyzed. Survivors presented an intestinal microbiome with slight change and more intensive interspecies cooperation, while a distinct gene expression profile related to glycometabolism and immunomodulation was observed, resulting in lower-level inflammation in intestinal tissue. Genes related to FoxO, Insulin, and Glucagon signaling pathways, such as g6pc, socs2, and foxg1, correlated positively with intestinal Eubacterium_coprostanoligenes_Group, Mannheimia, Leptotrichia, and Shewanella, corresponding to a higher serum glucose level and IgM titer in surviving fish. Besides, Pseudomonas and Shewanella, with higher abundance in surviving fish, showed antagonism towards the pathogen in vitro, and a positive correlation with serum glucose level and IgM titer, respectively. Co-cultures promoted these antagonism effects and these effects connected with glucose concentration. Glucose supplementation to fish raised the survival rate significantly. In general, glycometabolism homeostasis is critical for fish to survive A. hydrophila infection. Metabolism modulation would be a potential approach to facilitate bacterial infection resistance.