Study of the impact of cranberry extract on the virulence factors and biofilm formation by Enterococcus faecalis strains isolated from urinary tract infections

Int J Food Sci Nutr. 2016 Dec;67(8):1005-16. doi: 10.1080/09637486.2016.1211996. Epub 2016 Jul 26.

Abstract

Drinking of cranberry fruit juice and application of commercial preparations containing the cranberry extracts are recommended in the prevention and treatment of urinary tract infections (UTIs), especially in women with recurrent UTIs. Many studies focus on the activity of cranberries against uropathogenic Escherichia coli (E. coli) strains. However, the knowledge of the cranberry effect on Gram-positive Enterococcus faecalis (E. faecalis) is limited. Therefore, the aim of our study was to establish the activity of commercial concentrated cranberry extract on the growth, virulence factors and biofilm formation of E. faecalis strains isolated from urine. Minimal inhibitory concentrations (MICs) of cranberry extract were determined by the broth microdilution method. Disc diffusion method was used to determine antimicrobial susceptibility. The impact of cranberry extract on bacterial survival, hydrophobicity, synthesis of lipase, lecithinase, DNase, hemolysin, gelatinase and biofilm mass was determined. Results show that cranberry extract inhibits the growth, enzymatic activities of bacteria and limits biofilm formation. The antibacterial activities of the studied cranberry extract confirm that it could be successfully used in prevention of UTIs caused by E. faecalis.

Keywords: Antimicrobial; Enterococcus; UTIs; cranberry extract.

MeSH terms

  • Biofilms / drug effects
  • Biofilms / growth & development
  • Enterococcus faecalis / drug effects*
  • Enterococcus faecalis / pathogenicity*
  • Enterococcus faecalis / physiology
  • Fruit and Vegetable Juices / analysis
  • Genes, Bacterial / drug effects
  • Gram-Positive Bacterial Infections / microbiology
  • Gram-Positive Bacterial Infections / prevention & control*
  • Humans
  • In Vitro Techniques
  • Plant Extracts / pharmacology
  • Urinary Tract Infections / microbiology
  • Urinary Tract Infections / prevention & control*
  • Vaccinium macrocarpon / chemistry*
  • Virulence Factors / biosynthesis
  • Virulence Factors / genetics

Substances

  • Plant Extracts
  • Virulence Factors