Safety Aspect of Enterococcus faecium FL31 Strain and Antibacterial Mechanism of Its Hydroxylated Bacteriocin BacFL31 against Listeria monocytogenes

Biomed Res Int. 2018 Nov 1:2018:5308464. doi: 10.1155/2018/5308464. eCollection 2018.

Abstract

In previous work we have isolated and identified a new strain called Enterococcus faecium FL31. The active compound secreted by this strain, "BacFL31", has been purified and characterized. In the present study, safety aspect, assessed by microbiological and molecular tests, demonstrated that Enterococcus faecium FL31 was susceptible to relevant antibiotics, free of hemolytic, gelatinase, DNase, and lipase activities. In addition, it did not harbor virulence and antibiotic resistance genes. Combined SYTOX Green dye and UV-absorbing experiments, along with released extracellular potassium and transmembrane electrical potential measurements, showed that pure BacFL31 at a concentration of 1×MIC (50 μg/mL) could damage cytoplasmic membrane of the pathogen Listeria monocytogenes ATCC19117. The same concentration causes the leakage of its intracellular constituents and leads to the destruction of this pathogenic microorganism. In summary, this work reflected characteristics of Enterococcus faecium FL31 strain and its bacteriocin in terms of functional and safety perspectives.

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology*
  • Bacteriocins / chemistry
  • Bacteriocins / isolation & purification
  • Bacteriocins / pharmacology*
  • Drug Resistance, Bacterial / drug effects
  • Enterococcus faecium / chemistry*
  • Humans
  • Hydroxylation
  • Listeria monocytogenes / drug effects*
  • Listeria monocytogenes / pathogenicity
  • Listeriosis / drug therapy
  • Listeriosis / microbiology
  • Membrane Potentials / drug effects
  • Organic Chemicals / chemistry
  • Potassium / chemistry

Substances

  • Anti-Bacterial Agents
  • Bacteriocins
  • Organic Chemicals
  • SYTOX Green
  • Potassium