The Antimicrobial Peptide Temporin G: Anti-Biofilm, Anti-Persister Activities, and Potentiator Effect of Tobramycin Efficacy Against Staphylococcus aureus

Abstract

Bacterial biofilms are a serious threat for human health, and the Gram-positive bacterium Staphylococcus aureus is one of the microorganisms that can easily switch from a planktonic to a sessile lifestyle, providing protection from a large variety of adverse environmental conditions. Dormant non-dividing cells with low metabolic activity, named persisters, are tolerant to antibiotic treatment and are the principal cause of recalcitrant and resistant infections, including skin infections. Antimicrobial peptides (AMPs) hold promise as new anti-infective agents to treat such infections. Here for the first time, we investigated the activity of the frog-skin AMP temporin G (TG) against preformed S. aureus biofilm including persisters, as well as its efficacy in combination with tobramycin, in inhibiting S. aureus growth. TG was found to provoke ~50 to 100% reduction of biofilm viability in the concentration range from 12.5 to 100 µM vs ATCC and clinical isolates and to be active against persister cells (about 70–80% killing at 50–100 µM). Notably, sub-inhibitory concentrations of TG in combination with tobramycin were able to significantly reduce S. aureus growth, potentiating the antibiotic power. No critical cytotoxicity was detected when TG was tested in vitro up to 100 µM against human keratinocytes, confirming its safety profile for the development of a new potential anti-infective drug, especially for treatment of bacterial skin infections.

First-in-Class Cyclic Temporin L Analogue: Design, Synthesis, and Antimicrobial Assessment

“…Preformed biofilms of S. aureus ATCC 25923 and A. baumannii ATCC 19606 were obtained as previously reported. 77 Microbial cultures were grown in Luria-Bertani broth (LB) at 37 °C to an optical density (OD) of 0.8 (λ = 590 nm) and then diluted in LB to a cell density of 1 × 10 6 colony-forming units (CFUs)/mL. Aliquots of 100 μL were dispensed into the wells of a 96-well plate, which was incubated for 20 h at 37 °C to allow biofilm formation.…”

Generation of truncated derivatives through in silico enzymatic digest of peptide GV30 target MRSA both in vitro and in vivo

“…After biofilm formation, a high concentration of antibiotic (4 μg/ml vancomycin) was prepared to treat the biofilm for 24 h, followed by a washing step twice with PBS. Then, different concentrations of peptides were added to each well and incubated for 24 h. The minimum anti-persister cells eradication concentration was determined by the same method as in the anti-biofilm assay described in 2.8 [37] .…”

Positive biofilms to guide surface microbial ecology in livestock buildings

“…Honey bee products (bee venom, propolis or honey), plant essential oils and microorganism metabolites have shown antibacterial and antibiofilm activities [ [105] , [106] , [107] ]. A wide variety of organisms such as insects and amphibians can also secrete antimicrobial peptides with anti-biofilm activities against pathogenic bacteria [ [108] , [109] , [110] ]. The use of phages (viruses that infect bacteria) to attack target pathogens is a promising solution that is already used in different sectors in some countries [ 111 ].…”