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.

• Klíčová slova
• antibacterial peptides, antibiotics, bacteria, infections, multidrug resistance,
• Publikační typ
• časopisecké články MeSH

Antibiotic-resistant bacterial infections have become global issues for public health, which increases the utter need to develop alternatives to antibiotics. Here, the HSER (Homo sapiens retinoic acid receptor) peptide was designed from retinoic acid receptor responder protein 2 of Homo sapiens, and was conjugated with synthesized CQDs (carbon quantum dots) for enhanced antibacterial activity in combination, as individually they are not highly effective. The HSER-CQDs were characterized using spectrophotometer, HPLC coupled with electrospray-ionization quadrupole time-of-flight mass spectrometer (ESI-qTOF) mass spectrometer, zeta potential, zeta size, and FTIR. Thereafter, the antibacterial activity against Vancomycin-Resistant Staphylococcus aureus (VRSA) and Escherichia coli (carbapenem resistant) was studied using growth curve analysis, further supported by microscopic images showing the presence of cell debris and dead bacterial cells. The antibacterial mechanism of HSER-CQDs was observed to be via cell wall disruption and also interaction with gDNA (genomic DNA). Finally, toxicity test against normal human epithelial cells showed no toxicity, confirmed by microscopic analysis. Thus, the HSER-CQDs conjugate, having high stability and low toxicity with prominent antibacterial activity, can be used as a potential antibacterial agent.

• Klíčová slova
• antibacterial activity, antibiotic-resistant, bacterial infections, carbon quantum dots, toxicity,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Increase in vancomycin (Van)-resistant bacterial strains including vancomycin-resistant Staphylococcus aureus (VRSA) and lack of new effective antibiotics have become a formidable health problem. MATERIALS AND METHODS: We designed a new conjugate composed of Van and a peptide Hecate (Hec; Van/Hec), and its potential antimicrobial activity was evaluated. RESULTS: Results from disk diffusion test, time-kill assay, determination of minimum inhibitory concentration (MIC), microscopy, and comet assay showed strong antimicrobial effects of Van/Hec against wild-type, methicillin-resistant Staphylococcus aureus (MRSA) and VRSA. Microscopy revealed that the exposure to Van/Hec results in disruption of bacterial cell integrity in all tested strains, which was not observed in case of Van or Hec alone. CONCLUSION: Overall, we showed that the preparation of conjugates from antibiotics and biologically active peptides could help us to overcome the limitation of the use of antibiotic in the treatment of infections caused by multidrug-resistant bacteria.

• Klíčová slova
• Staphylococcus aureus, antibacterial, antibiotic resistance, peptide, vancomycin,
• Publikační typ
• časopisecké články MeSH