Teicoplanin is a natural lipoglycopeptide antibiotic with a similar activity spectrum as vancomycin; however, it has with the added benefit to the patient of low cytotoxicity. Both teicoplanin and vancomycin antibiotics are actively used in medical practice in the prophylaxis and treatment of severe life-threatening infections caused by gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, Enterococcus faecium and Clostridium difficile. The expression of vancomycin Z (vanZ), encoded either in the vancomycin A (vanA) glycopeptide antibiotic resistance gene cluster or in the genomes of E. faecium, as well as Streptococcus pneumoniae and C. difficile, was shown to specifically compromise the antibiotic efficiency through the inhibition of teicoplanin binding to the bacterial surface. However, the exact mechanisms of this action and protein structure remain unknown. In this study, the three-dimensional structure of VanZ from E. faecium EnGen0191 was predicted by using the I-TASSER web server. Based on the VanZ structure, a benzimidazole based ligand was predicted to bind to the VanZ by molecular docking. Importantly, this new ligand, named G3K, was further confirmed to specifically inhibit VanZ-mediated resistance to teicoplanin in vivo.

• Keywords
• Enterococcus faecium, MD simulation, Staphylococcus aureus, antibiotic resistance, benzimidazole, docking, ligands, lipoglycopeptide antibiotic, teicoplanin VanZ,
• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Bacterial drug effects   MeSH
• Bacterial Proteins metabolism   MeSH
• Gram-Positive Bacterial Infections drug therapy   MeSH
• Gram-Positive Bacteria drug effects   MeSH
• Humans MeSH
• Lipoglycopeptides pharmacology   MeSH
• Microbial Sensitivity Tests methods   MeSH
• Molecular Docking Simulation methods   MeSH
• Teicoplanin pharmacology   MeSH
• Vancomycin pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacterial Proteins MeSH
• Lipoglycopeptides MeSH
• Teicoplanin MeSH
• Vancomycin MeSH

An inexorable switch from antibiotics has become a major desideratum to overcome antibiotic resistance. Bacteriocin from Lactobacillus casei, a cardinal probiotic was used to design novel antibacterial peptides named as Probiotic Bacteriocin Derived and Modified (PBDM) peptides (PBDM1: YKWFAHLIKGLC and PBDM2: YKWFRHLIKKLC). The loop-shaped 3D structure of peptides was characterized in silico via molecular dynamics simulation as well as biophysically via spectroscopic methods. Thereafter, in vitro results against multidrug resistant bacterial strains and hospital samples demonstrated the strong antimicrobial activity of PBDM peptides. Further, in vivo studies with PBDM peptides showed downright recovery of balb/c mice from Vancomycin Resistant Staphylococcus aureus (VRSA) infection to its healthy condition. Thereafter, in vitro study with human epithelial cells showed no significant cytotoxic effects with high biocompatibility and good hemocompatibility. In conclusion, PBDM peptides displayed significant antibacterial activity against certain drug resistant bacteria which cause infections in human beings. Future analysis are required to unveil its mechanism of action in order to execute it as an alternative to antibiotics.

• Keywords
• antibacterial peptides, antibiotics, bacteria, infections, multidrug resistance,
• Publication type
• Journal Article MeSH