Beyond antibiotics: a new anti-virulence strategy combating ESBL-producing Klebsiella pneumoniae by targeting periplasmic trehalase

The rise of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) poses a serious public health threat with high mortality and limited treatment options due to its broad resistance. This study investigates the role of the periplasmic trehalase (TreA) which is associated with virulence and significantly upregulated in resistant strains, to identify potential new therapeutic strategies. We generated a treA-deficient mutant (ΔtreA) from an ESBL-Kp isolate and conducted a phenotypic comparison with the wild-type strain. The assessments focused on their growth, tolerance to temperature stress, survival in antibiotic-treated macrophages, biofilm formation, and virulence in a murine lung infection model. Deletion of treA significantly impaired bacterial growth and reduced biomass during the stationary phase. The mutant displayed compromised thermotolerance at elevated temperatures. Under antibiotic treatment, ΔtreA exhibited reduced intracellular survival in macrophages and diminished proliferative capacity after antibiotic adaptation. Biofilm formation was significantly attenuated, with lower optical density values observed across all dilutions. In murine models, treA deficiency led to reduced virulence, as evidenced by improved survival rates, less weight loss, and lower pulmonary bacterial loads. TreA acts as a key metabolic determinant for virulence in ESBL-Kp, underscoring its potential as a target for anti-virulence strategies against this multidrug-resistant pathogen.