Author(s):
Oliveira, A. ; Ribeiro, Henrique ; Silva, A. ; Silva, Maria Daniela ; Sousa, Jéssica ; Rodrigues, Célia F. ; Melo, Luís D. R. ; Henriques, Ana Filipa ; Sillankorva, Sanna
Date: 2017
Persistent ID: http://hdl.handle.net/1822/48125
Origin: RepositóriUM - Universidade do Minho
Project/scholarship:
info:eu-repo/grantAgreement/FCT/5876/147337/PT;
info:eu-repo/grantAgreement/FCT/5876-PPCDTI/126270/PT
;
info:eu-repo/grantAgreement/FCT/COMPETE/126270/PT;
info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBPD%2F69356%2F2010/PT;
info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F93078%2F2013/PT;
Subject(s): E. coli; honey; bacteriophage; biofilms; synergy; Science & Technology
Description
Chronic wounds afford a hostile environment of damaged tissues that allow bacterial proliferation and further wound colonization. Escherichia coli is among the most common colonizers of infected wounds and it is a prolific biofilm former. Living in biofilm communities, cells are protected, become more difficult to control and eradicate, and less susceptible to antibiotic therapy. This work presents insights into the proceedings triggering E. coli biofilm control with phage, honey and their combination, achieved through standard antimicrobial activity assays, zeta potential and flow cytometry studies and further visual insights sought by SEM and TEM microscopy. Two Portuguese honeys (PF2 and U3) with different floral origin and an E. coli specific phage (EC3a), possessing depolymerase activity, were tested against 24 h and 48 h-old biofilms. Synergic and additive effects were perceived in some phage-honey experiments. Combined therapy prompted similar phenomena in biofilm cells, visualized by electron microscopy, as the individual treatments. Honey caused minor membrane perturbations to complete collapse and consequent discharge of cytoplasmic content, and phage completely destroyed cells leaving only vesicle-like structures and debris. Our experiments show that the addition of phage to low honey concentrations is advantageous, and that even 4-fold diluted honey combined with phage, presents no loss of antibacterial activity towards E. coli. Portuguese honeys possess excellent antibiofilm activity and may be potential alternative therapeutic agents in biofilm-related wound infection. Furthermore, to our knowledge this is the first study that assessed the impacts of phage-honey combinations in bacterial cells. The synergistic effect obtained was shown to be promising, since the antiviral effect of honey limits the emergence of phage resistant phenotypes.
This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project PTDC/CVT-EPI/4008/2014 (POCI-010145-FEDER-016598). AO and CR acknowledge financial support from the Portuguese Foundation for Science and Technology (FCT) through the grants SFRH/BPD/69356/2010 and SFRH/BD/93078/2013. SS is an Investigador FCT (IF/01413/2013).
info:eu-repo/semantics/publishedVersion
