Antibiofilm and Antimicrobial Activity of Polyethylenimine: An Interesting Compound for Endodontic Treatment.
Bacteria levels of necrotic teeth are greatly reduced after endodontic treatment procedures but the presence of persisting microorganisms leads to continuous efforts to develop materials with antimicrobial properties. The purpose of the study was to determine the antimicrobial activity of polyethylenimine (PEI) against common bacteria and yeasts, regarding planktonic cells and biofilm, and to clarify its antimicrobial mechanism of action through flow cytometry.



The antibiofilm and antimicrobial effect of PEI was determined against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Candida albicans strains using reference protocols. The effect of PEI was evaluated regarding adhesion, biofilm formation and biofilm disaggregation. In order to understand PEI cellular effects flow cytometric analysis was performed with different fluorescent markers.



It was verified that minimal inhibitory concentrations (MIC) values and minimal lethal concentrations (MLC) obtained for PEI were similar and ranged between 50 and 400 mg/l, proving the microbicidal and fungicidal activity of this compound. Antibiofilm activity was also proved for all the microorganisms. Severe lesion of the membrane and cell depolarization was demonstrated.



Polyethylenimine showed antimicrobial and antibiofilm activity against microorganisms often associated with apical periodontitis.



Theoretically, prolonging the antibacterial effects of materials used in endodontics may be interesting to help prevent reinfection and possibly to affect residual bacteria that survived the treatment procedures.
Professor, Department of Endodontics, Faculty of Dental Medicine University of Porto, Porto, Portugal, Phone: +351 220 901 100, e-mail: joana.barros.c@gmail.com.
Joana
J
Barros
Department of Microbiology, Faculty of Medicine, University of Porto, Porto; Cardiovascular Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal.
Ana
A
Dias
Department of Metallurgical and Materials Engineering Faculty of Engineering, University of Porto, Porto; Centre for Mechanical Engineering of the University of Coimbra Portugal.
Miguel A
MA
Rodrigues
Department of Microbiology, Faculty of Medicine, University of Porto, Porto; Cardiovascular Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal.
Cidália
C
Pina-Vaz
Department of Metallurgical and Materials Engineering Faculty of Engineering, University of Porto, Porto; Centre for Mechanical Engineering of the University of Coimbra Portugal.
Maria A
MA
Lopes
Department of Endodontics, Faculty of Dental Medicine University of Porto, Porto, Portugal.
Irene
I
Pina-Vaz
D000890:Anti-Infective Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects; D004708:Endodontics / Q000379:methods; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D011094:Polyethyleneimine / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects
D000890:Anti-Infective Agents; D011094:Polyethyleneimine
Antimicrobial activity; Biofilms; Endodontic treatment; Polyethylenimine.