is Involved in the Decrease of Biofilm by the Antimicrobial Peptide Cec4.

Purpose: The emergence of carbapenem-resistant (CRAB) poses great difficulties in clinical treatment, and has been listed by the World Health Organization as a class of pathogens in urgent need of new antibiotic development. In our previous report, the novel antimicrobial peptide Cec4 showed great potential in decreasing the clinical CRAB biofilm, but its mechanism of action is still illusive. Therefore, in order to evaluate the clinical therapeutic potential of Cec4, it is necessary to explore the mechanism of how Cec4 decreases mature biofilms.

Methods: Key genes involved in the removal of CRAB biofilms by Cec4 were analyzed using transcriptomics. Based on the results of the bioinformatics analysis, the CRISPR-Cas9 method was used to construct the deletion strain of the key gene. The pYMAb2 plasmid was used for the complementation strain construction. Finally, the roles of key genes in biofilm removal by Cec4 were determined by crystal violet staining, podocyte staining, laser confocal imaging, and MBC and MBEC.

Results: Combined with transcriptome analysis, we hypothesized that is a key gene involved in the removal of CRAB biofilms by Cec4. Deletion of the gene did not affect growth, but decreased capsule thickness, increasing biofilm production, and made biofilm-state more sensitive to Cec4.

Conclusion: Cec4 decreases biofilms formed by CRAB targeting . Deletion of the gene results in an increase in biofilms and greater sensitivity to Cec4, which enhances the removal of biofilms by Cec4.