Multifunctional Acidocin 4356 Combats Pseudomonas aeruginosa through Membrane Perturbation and Virulence Attenuation: Experimental Results Confirm Molecular Dynamics Simulation

Abstract

A longstanding awareness in generating resistance to common antimicrobial therapies by Gram-negative bacteria has made them a major threat to global health. The application of antimicrobial peptides as a therapeutic agent would be a great opportunity to combat bacterial diseases. Here, we introduce a new antimicrobial peptide (∼8.3 kDa) from probiotic strain Lactobacillus acidophilus ATCC 4356, designated acidocin 4356 (ACD). This multifunctional peptide exerts its anti-infective ability against Pseudomonas aeruginosa through an inhibitory action on virulence factors, bacterial killing, and biofilm degradation. Reliable performance over tough physiological conditions and low hemolytic activity confirmed a new hope for the therapeutic setting. Antibacterial kinetic studies using flow cytometry technique showed that the ACD activity is related to the change in permeability of the membrane. The results obtained from molecular dynamic (MD) simulation were perfectly suited to the experimental data of ACD behavior. The structure-function relationship of this natural compound, along with the results of transmission electron microscopy analysis and MD simulation, confirmed the ability of the ACD aimed at enhancing bacterial membrane perturbation. The peptide was effective in the treatment of P. aeruginosa infection in mouse model. The results support the therapeutic potential of ACD for the treatment of Pseudomonas infections. IMPORTANCE Multidrug-resistant bacteria are a major threat to global health, and the Pseudomonas bacterium with the ability to form biofilms is considered one of the main causative agents of nosocomial infections. Traditional antibiotics have failed because of increased resistance. Thus, finding new biocompatible antibacterial drugs is essential. Antimicrobial peptides are produced by various organisms as a natural defense mechanism against pathogens, inspiring the possible design of the next generation of antibiotics. In this study, a new antimicrobial peptide was isolated from Lactobacillus acidophilus ATCC 4356, counteracting both biofilm and planktonic cells of Pseudomonas aeruginosa. A detailed investigation was then conducted concerning the functional mechanism of this peptide by using fluorescence techniques, electron microscopy, and in silico methods. The antibacterial and antibiofilm properties of this peptide may be important in the treatment of Pseudomonas infections.

Transcriptomic Analysis Revealed Antimicrobial Mechanisms of Lactobacillus rhamnosus SCB0119 against Escherichia coli and Staphylococcus aureus

“…The potential effects of CFS on cell morphology and structure of E. coli ATCC25922 and S. aureus ATCC6538 were determined by SEM and TEM [ 56 , 57 ]. Briefly, bacterial dilutions (10 7 CFU/mL) in LB medium were supplemented with 1/2 MIC of CFS and incubated for 10 h at 37 °C by shaking.…”

Lactobacillus spp. na vanguarda: abordagem terapêutica não-medicamentosa no combate efetivo à Pseudomonas aeruginosa

“…37 Outro exemplo de metabólito produzido por espécies de Lactobacillus, que apresenta ação antimicrobiana contra P. aeruginosa, é a acidocina 4356, um peptídeo antimicrobiano produzido pela espécie L. acidophilus, o qual apresenta capacidade de inibição dos fatores de virulências, morte do micro-organismo e degradação de biofilmes. 38 Lactobacillus são investigados em conjunto com diferentes tipos de antibióticos. Estudos já demonstram que espécies de Lactobacillus associadas a antibióticos favoreceram o tratamento contra a colonização da microbiota intestinal de bactérias multirresistentes, como, por exemplo, P. aeruginosa.…”

Anti-Pseudomonas aeruginosa activity of natural antimicrobial peptides when used alone or in combination with antibiotics

“…Compared with the control group, the peptide-treated mouse lung slices exhibited the decreased recruitment of macrophages and lung cells, as well as a reduction in epithelial hyperplasia and structural degeneration. Mechanism of action experiments revealed that ACD not only enhanced bacterial membrane perturbation, but also reduced the production of P. aeruginosa virulence factors, such as pyoverdine siderophore, pyocyanin toxin, secretory protease, and elastase enzyme ( Modiri et al, 2020 ). Moreover, it had a low hemolytic activity of less than 20% on human erythrocytes at a concentration of 400 μg/mL, indicating its potential as a promising therapeutic compound.…”

“…In addition to their ability to bind to bacterial membrane lipids and enhance membrane permeability, Lynronne-1 In addition to rumen microbiome, bacteriocins produced by lactic acid bacteria (LAB) had been extensively studied due to their safety and utility. Acidocin 4356 (ACD) is a novel bacteriocin with a size of 8.3 kDa, which was isolated from Lactobacillus acidophilus ATCC 4356 (Modiri et al, 2020). ACD had antimicrobial activity against both E. coli and P. aeruginosa, causing 35 and 80% inhibition of their growth at the same concentration.…”