Cbf-14, a cationic peptide derived from a cathelin-like domain, was designed by inserting the highly ahelical
sequence RLLR into an antibacterial sequence and deleting the inactive amino acids in Cbf-K16.
Clinical penicillin-resistant isolates as well as NDM-1-carrying Escherichia coli and a correspondingly
infected mice model were employed to evaluate Cbf-14 antibacterial activity. The results showed that
Cbf-14 possessed potent antimicrobial effects with an MIC of 8e64 mg/ml, and killed almost all bacteria
within 240 min. Cbf-14-treated mice achieved an 80% survival rate and approximate 2.5 log unit
reduction in CFU in tissues; additionally, this peptide significantly suppressed the production of proinflammatory
cytokines by the disaggregation of lipopolysaccharide (LPS), suggesting its antiinflammatory
effects. Furthermore, Cbf-14, concentration higher than 2 MIC value, increased membrane
uptake to NPN and PI dye by 96.2% and 63.7%, respectively, neutralised the negative zeta potential
of LPS and bacteria surface, and induced 100% leakage of liposome-entrapped calcein and cytoplasmic
membrane disruption of E. coli, indicating obvious membrane permeation. Finally, it bound to DNA and
respectively evoked 85.0% and 63.3% inhibition of gene replication and protein expression of NDM-1 at
sub-MIC concentration in E. coli BL21 (DE3)-NDM-1. These data indicated that Cbf-14 possessed effective
antimicrobial activity against penicillin-resistant bacteria in vitro/vivo through membrane disruption,
DNA binding, down-regulating NDM-1 expression by plasmid replication inhibition, and antiinflammatory
activity by LPS disaggregation, suggesting a potential anti-infective clinical agent