Unraveling the Unknown: Characterization of a Novel Antimicrobial Compound Found in Klebsiella pneumoniae

Klebsiella pneumoniae, a pathogenic bacterium resistant to numerous antimicrobials, is a worldwide health issue due to its ability to cause healthcare-associated diseases such as pneumonia and urinary tract infections. This study investigated an antimicrobial compound secreted by K. pneumoniae. The compound was found to possess inhibitory activity against Enterobacteriaceae members, including other Klebsiella pneumoniae strains, Citrobacter freundii, and Enterobacter cloacae. The inhibitory activity is mediated via a secreted protein that is active across a wide range of pH and temperature conditions. Higher concentrations of the compound enhanced antimicrobial activity. The antimicrobial protein suppressed biofilm formation during both the attachment and maturation phases. The antimicrobial protein gene was identified through transposon mutagenesis, sequencing, then PCR amplified and cloned into expression cells for purification. This research provides strong evidence that the antimicrobial protein is an uncharacterized bacteriocin and highlights its potential as a candidate in innovative treatments for antibiotic-resistant bacterial infections.