Fernanda Katherine Sacoto-Figueroa1, Helia Magali Bello-Toledo2,3, Gerardo Enrique González-Rocha2,3, Luis Luengo Machuca4, Celia A Lima2,3,4, Manuel Meléndrez-Castro5, Gabriela Alejandra Sánchez-Sanhueza6,7. 1. Departamento de Endodoncia, Facultad de Odontología, Unidad Académica de Salud y Bienestar, Universidad Católica de Cuenca, Cuenca, Ecuador. 2. Laboratorio de Investigación en Agentes Antibacterianos (LIAA), Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile. 3. Núcleo Milenio para la Investigación Colaborativa en Resistencia Antimicrobiana - Microb-R, SCL, Pudahuel, Chile. 4. Departamento de Salud Pública, Facultad de Odontología, Universidad de Concepción, Concepción, Chile. 5. Grupo de Investigación Avanzada de Nanocomposites (GINA), Laboratorio de Materiales Híbridos, Departamento de Ingeniería de Materiales, Facultad de Ingeniería, Universidad de Concepción, Concepción, Chile. 6. Laboratorio de Investigación en Agentes Antibacterianos (LIAA), Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile. gasanchez@udec.cl. 7. Departamento de Odontología Restauradora, Facultad de Odontología, Universidad de Concepción, Concepción, Chile. gasanchez@udec.cl.
Abstract
OBJECTIVE: To carry out molecular characterization and determine the antibacterial activity of oral antibiotics and copper nanoparticles (Cu-NPs) against endodontic strains isolated from persistent infections. MATERIALS AND METHODS: Root canal samples from 24 teeth in different patients with persistent endodontic infections were obtained. The isolated strains were identified by biochemical tests and 16S rDNA sequencing. Genotyping was achieved by molecular methods. The antibacterial activity of antibiotics and copper nanostructures was determined by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Furthermore, a time-kill kinetics assay was evaluated. Nonparametric tests (Kruskal-Wallis ANOVA) were performed (p value <0.05). RESULTS: Twenty-one isolated strains were identified. Six isolates of Enterococcus faecalis were grouped into two clusters of three isolates each, two of which were clones. All were clarithromycin-resistant and erythromycin. Eight Pseudomonas putida presented two clusters, two Pseudomonas spp. were not clonal, and all were resistant to the tested antibiotics except tetracycline. Two of five strains of Cutibacterium acnes were clonal, and all were resistant only to metronidazole. The lowest MIC and MBC values were obtained with Cu-NPs. Time-kill kinetics using Cu-NPs showed a significant decrease in all tested species within 4 h and reached 100% in 2 h for C. acnes. CONCLUSION: In this study, in relation to health care-associated infections, endodontic strains of each species isolated at least in one patient were polyclonal. In Pseudomonas spp., at least one clone was shared between patients. E. faecalis and C. acnes strains were susceptible to low Cu-NP concentrations, while Pseudomonas spp. strains were resistant. CLINICAL RELEVANCE: Assessing and keeping track of the susceptibility of clinical strains to antimicrobial compounds is important for the clinical outcome. Based on our results, Cu-NPs could be an alternative for endodontic treatment, in order to avoid selection of resistant strains.
OBJECTIVE: To carry out molecular characterization and determine the antibacterial activity of oral antibiotics and copper nanoparticles (Cu-NPs) against endodontic strains isolated from persistent infections. MATERIALS AND METHODS: Root canal samples from 24 teeth in different patients with persistent endodontic infections were obtained. The isolated strains were identified by biochemical tests and 16S rDNA sequencing. Genotyping was achieved by molecular methods. The antibacterial activity of antibiotics and copper nanostructures was determined by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Furthermore, a time-kill kinetics assay was evaluated. Nonparametric tests (Kruskal-Wallis ANOVA) were performed (p value <0.05). RESULTS: Twenty-one isolated strains were identified. Six isolates of Enterococcus faecalis were grouped into two clusters of three isolates each, two of which were clones. All were clarithromycin-resistant and erythromycin. Eight Pseudomonas putida presented two clusters, two Pseudomonas spp. were not clonal, and all were resistant to the tested antibiotics except tetracycline. Two of five strains of Cutibacterium acnes were clonal, and all were resistant only to metronidazole. The lowest MIC and MBC values were obtained with Cu-NPs. Time-kill kinetics using Cu-NPs showed a significant decrease in all tested species within 4 h and reached 100% in 2 h for C. acnes. CONCLUSION: In this study, in relation to health care-associated infections, endodontic strains of each species isolated at least in one patient were polyclonal. In Pseudomonas spp., at least one clone was shared between patients. E. faecalis and C. acnes strains were susceptible to low Cu-NP concentrations, while Pseudomonas spp. strains were resistant. CLINICAL RELEVANCE: Assessing and keeping track of the susceptibility of clinical strains to antimicrobial compounds is important for the clinical outcome. Based on our results, Cu-NPs could be an alternative for endodontic treatment, in order to avoid selection of resistant strains.
Authors: G Sánchez-Sanhueza; H Bello-Toledo; G González-Rocha; A T Gonçalves; V Valenzuela; C Gallardo-Escárate Journal: Int Endod J Date: 2018-06-09 Impact factor: 5.264
Authors: P I Diaz; A K Dupuy; L Abusleme; B Reese; C Obergfell; L Choquette; A Dongari-Bagtzoglou; D E Peterson; E Terzi; L D Strausbaugh Journal: Mol Oral Microbiol Date: 2012-03-03 Impact factor: 3.563