Isobavachalcone enhances sensitivity of colistin-resistant Klebsiella pneumoniae: In vitro and in vivo proof-of-concept studies.

Objective: Antibiotic resistance poses a considerable worldwide concern, particularly in clinical environments where drug-resistant Gram-negative bacteria like Klebsiella pneumoniae (K. pneumoniae) present a major challenge. The objective of this research was to investigate the mechanisms by which isobavachalcone (IBC) restores the sensitivity of K. pneumoniae to colistin in vitro and to validate the synergistic therapeutic effect in vivo.

Results: The results indicate that the combined administration of colistin and IBC exhibits a potent antibacterial effect both in vitro and in vivo. The in vitro concurrent administration of colistin and IBC resulted in increased membrane permeability, compromised cell integrity, diminished membrane fluidity, and disrupted membrane homeostasis. Additionally, this combination reduced biofilm production, inhibited the synthesis of the autoinducer factor, altered membrane potential, and affected levels of reactive oxygen species and adenosine triphosphate synthesis, ultimately leading to bacterial death. In vivo experiments on Galleria mellonella and mice demonstrated that the co-administration of colistin and IBC increased the survival rate and significantly reduced pathological damage compared to colistin alone.

Conclusion: These results suggested that IBC effectively restores the sensitivity of colistin by inducing physical disruption of bacterial membranes and oxidative stress. The combination therapy of colistin and IBC presents a viable and safe strategy to combat drug-resistant K. pneumoniae-associated infections.