Anti-biofilm activity of antimicrobial peptide CRAMP-34 by regulating 2-dehydro-3-deoxy-D-gluconate 5-dehydrogenase (KduD) of Escherichia coli

Abstract

Escherichia coli (E. coli) has high antimicrobial resistance and is globally prevalent, forming aggressive and dense bacterial biofilms. Previous studies have shown that the mouse antimicrobial peptide CRAMP-34 eradicates biofilms. The current study aimed to investigate the mechanism of CRAMP-34 on the biofilm of a clinically isolated E. coli (No. Ec032) with strong biofilm formation ability. An unreported gene kduD associated with Ec032 biofilm formation was identified by transposon mutation technology, and the kduD gene deletion strain Ec032ΔkduD was constructed using CRISPR/Cas9. Furthermore, the deletion of kduD gene reduced the motility of Ec032 and inhibited the aggregation of bacteria to form mature biofilms. Also, CRAMP-34 inhibited the motility of Ec032 and significantly cleared the mature biofilm. RT-qPCR showed that CRAMP-34 significantly downregulated the biofilm-related genes, including ycgR, papG, csgD, bcsA, uxaA, uxuA, kduD, and araE. These findings indicated that KduD protein is a potential target of CRAMP-34. Therefore, this study provides the foundation for the prevention and treatment of E. coli biofilm and also develops CRAMP-34 as a new biofilm scavenger.