Compound MTEBT-3 as a Potent Anti-Klebsiella Pneumoniae Agent: In Vitro and In Vivo Efficacy, Favorable Safety, and Mechanistic Insights from Transcriptomics

The increasing prevalence of Klebsiella pneumoniae (KP) infections underscores an urgent need for novel therapeutic agents. This study aimed to comprehensively evaluate the antibacterial efficacy, in vivo therapeutic potential, preliminary safety profile, and mechanism of action of the compound MTEBT-3 against clinical isolates of KP. The minimum inhibitory concentration (MIC) of MTEBT-3 against 30 clinical isolates of KP was determined using the broth microdilution method. The membrane-disrupting effect of MTEBT-3 was investigated by measuring the permeability of both the inner and outer membranes. A murine skin infection model was established to assess in vivo treatment efficacy over a 14-day observation period. Systemic safety was evaluated via complete blood count analysis and histopathological examination. Transcriptomic profiling of MTEBT-3 treated bacteria was performed, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to identify affected biological processes and signaling pathways. MTEBT-3 exhibited potent antibacterial activity against all 30 clinical isolates, with MIC values ranging from 1 to 8 μg/mL. The results indicated that the permeability of both the inner and outer bacterial membranes increased significantly after treatment with MTEBT-3 (P< 0.05), demonstrating its membrane-disrupting effect on bacterial cell structure. In the murine infection model, the treatment group showed significantly enhanced wound healing compared with the model control group (P< 0.001). Blood routine tests and histopathological assessment revealed no significant signs of systemic toxicity, indicating favorable preliminary safety and biocompatibility. MTEBT-3 demonstrates strong in vitro and in vivo antibacterial effects against clinical K. pneumoniae isolates, along with a promising safety profile. Its mechanism may involve disruption of bacterial membrane integrity, impairment of energy metabolism, and interference with essential biological processes, supporting its potential as a candidate for anti-infective therapy. • MTEBT-3 is a novel antimicrobial agent effective against both CSKP and CRKP. • It acts through a multimodal mechanism independent of known resistance pathways. • Mechanistically, it disrupts membrane integrity and dysregulates iron homeostasis. • Transcriptomics further suggests suppression of key metabolic pathways. • It shows strong in vivo efficacy and biocompatibility in a wound infection model.