Barros Joana, Dias Ana, Rodrigues Miguel A, Pina-Vaz Cidália, Lopes Maria A, Pina-Vaz Irene
Professor, Department of Endodontics, Faculty of Dental Medicine University of Porto, Porto, Portugal, Phone: +351 220 901 100, e-mail:
Department of Microbiology, Faculty of Medicine, University of Porto, Porto; Cardiovascular Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal.
J Contemp Dent Pract. 2015 Jun 1;16(6):427-32. doi: 10.5005/jp-journals-10024-1701.
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.
根管治疗术后坏死牙的细菌水平大幅降低，但持续存在的微生物促使人们不断努力研发具有抗菌性能的材料。本研究的目的是确定聚乙烯亚胺（PEI）对常见细菌和酵母菌在浮游细胞和生物膜方面的抗菌活性，并通过流式细胞术阐明其抗菌作用机制。
采用参考方案测定PEI对粪肠球菌、金黄色葡萄球菌、大肠杆菌和白色念珠菌菌株的抗生物膜和抗菌效果。评估了PEI在粘附、生物膜形成和生物膜分解方面的作用。为了解PEI的细胞效应，使用不同的荧光标记进行流式细胞术分析。
证实PEI的最低抑菌浓度（MIC）值和最低致死浓度（MLC）相似，范围在50至400mg/l之间，证明了该化合物的杀菌和杀真菌活性。还证明了对所有微生物的抗生物膜活性。显示出膜的严重损伤和细胞去极化。
聚乙烯亚胺对常与根尖周炎相关的微生物具有抗菌和抗生物膜活性。
从理论上讲，延长牙髓病学中所用材料的抗菌作用可能有助于预防再感染，并可能影响在治疗过程中存活下来的残留细菌。
