Nicotinamide Mononucleotide Protects Against Hypervirulent Klebsiella pneumoniae Bloodstream Infection and Liver Injury

In clinical practice, hypervirulent Klebsiella pneumoniae often causes bloodstream infection and liver abscesses; however, the mechanism of liver abscess formation remains unclear. Nicotinamide mononucleotide has been reported to have potential therapeutic effects on sepsis, but its impact on bloodstream infection is still unclear. Supplementation with nicotinamide mononucleotide improved the survival rate, and the protective effects of NMN disappeared after macrophage depletion. Nicotinamide mononucleotide treatment can reduce inflammatory signaling pathway activation in bone marrow derived macrophages after hypervirulent Klebsiella pneumoniae infection, as well as the transcription of Il6, Il1b, and Cxcl2. Nicotinamide mononucleotide combined with antibiotic therapy blocked the formation of liver abscesses. The treatment regimen of nicotinamide mononucleotide combined with antibiotics effectively reduced the levels of inflammatory factors in the liver, inhibited the activation of the inflammatory signaling pathway, and reduced the infiltration of neutrophils into the liver. These results indicate that nicotinamide mononucleotide exerts a protective effect against hypervirulent Klebsiella pneumoniae bloodstream infection by inhibiting excessive inflammatory response, and nicotinamide mononucleotide has therapeutic potential for preventing liver injury caused by hypervirulent Klebsiella pneumoniae.