Antimicrobial, antiadhesive and antibiofilm activity of an ethanolic, anthocyanin‐rich blueberry extract purified by solid phase extraction

• Published in: Journal of applied microbiology Vol. 121; no. 3; pp. 693 - 703
• Main Authors: Silva, S., Costa, E.M., Mendes, M., Morais, R.M., Calhau, C., Pintado, M.M.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-09-2016; Wiley-Blackwell
• Subjects: Acinetobacter baumannii; Adhesion; adhesion inhibition; Adhesion tests; anthocyanins; Anthocyanins - analysis; Anti-Bacterial Agents - isolation & purification; antibiofilm activity; Antiinfectives and antibacterials; Antimicrobial activity; Antimicrobial agents; Bacteria; Bacteria - classification; Bacteria - drug effects; Bacterial Adhesion - drug effects; Bacterial Physiological Phenomena; Berries; Biofilms; Biofilms - drug effects; Blueberries; blueberry; Blueberry Plants - chemistry; E coli; Escherichia coli; Food contamination & poisoning; Kinetics; Microbial Sensitivity Tests; Microbiology; Microorganisms; Optical density; Pathogens; Plant Extracts - chemistry; Plant Extracts - pharmacology; Proteus mirabilis; Pseudomonas aeruginosa; Reagents; Solid Phase Extraction; Staphylococcus aureus; Vaccinium; Vaccinium corymbosum; Vaccinium corymbosum; adhesion inhibition; antimicrobial activity; anthocyanins; blueberry; antibiofilm activity
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.13215

Aims
The present work aimed to characterize the impact of an anthocyanin‐rich blueberry extract upon the growth, adhesion and biofilm formation of several pathogens including some multiresistant bacteria.
Methods and Results
A group comprised of reference strains and clinical multiresistant isolates of Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Acinetobacter baumannii and Staphylococcus aureus, were used to screen for antimicrobial activity. Microbial growth was determined through the measurement of the optical density while adhesion and biofilm formation was determined using the standard crystal violet staining procedure. The results showed that, while blueberry extract was only effective in hindering the growth of Staph. aureus and E. coli, it was capable of significantly inhibiting biofilm formation and bacterial adhesion for all micro‐organisms tested.
Conclusions
The extract demonstrated a considerable potential as a natural, alternative antimicrobial capable of either interfering with microbial growth or hamper the adhesion to surfaces, with Staph. aureus proving to be the most susceptible micro‐organism.
Significance and Impact of the Study
The overall study demonstrates the potential of anthocyanin extracts as natural effective alternative antimicrobial agents. Additionally, the extract's capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development while reducing the probability of infection.