| Autor: |
Chianca GC; Department of Basic Science, Universidade Federal Fluminense (UFF), Nova Friburgo, Rio de Janeiro, Brazil.; Faculdade de Farmácia, Universidade Estácio de Sá (UNESA), Nova Friburgo, Rio de Janeiro, Brazil., Antunes LAA; Department of Specific Formation, Universidade Federal Fluminense (UFF), Nova Friburgo, Rio de Janeiro, Brazil., Ornellas PO; Department of Specific Formation, Universidade Federal Fluminense (UFF), Nova Friburgo, Rio de Janeiro, Brazil., Neves FPG; Department of Microbiology and Parasitology, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro, Brazil., Póvoa HCC; Department of Basic Science, Universidade Federal Fluminense (UFF), Nova Friburgo, Rio de Janeiro, Brazil., Iorio NLPP; Department of Basic Science, Universidade Federal Fluminense (UFF), Nova Friburgo, Rio de Janeiro, Brazil. |
| Abstrakt: |
Objective: This study aimed to search for Enterococcus faecalis in children's deep carious dentine and characterize their virulence traits. Material and Methods: Eight isolates from 15 carious molars identified by 16S rDNA species-specific PCR as E. faecalis were included. These eight isolates were subject to identification by MALDI-TOF and characterized regarding: (i) bacterial aggregation and biofilm formation on polystyrene and glass, with/without saliva, as single or dual-species (associated to Streptococcus mutans ); (ii) environmental pH measurement before and after 24 h incubation; (iii) acidogenicity; (iv) gelatinase production; (v) macrophage adherence; and (vi) toxicity towards Caenorhabditis elegans . Statistical analyses were performed using two-way ANOVA/Tukey or Fisher's exact tests. Results: All isolates initially identified as E. faecalis by PCR were correctly identified as Lactobacillus by MALDI-TOF, being designated as Lactobacillus misidentified as Enterococcus (LME). These isolates produced biofilm in the presence of saliva and in the dual-species assays. Bacterial aggregation was only observed in the dual-species model. After 24 h, environmental pH dropped from 7.5 to 4.5 for seven of eight isolates, and to 4.0 in all dual-species models. LME isolates were acidogenic, none of them produced gelatinase or adhered to macrophages, but all presented toxicity towards C. elegans . Conclusions: No E. faecalis were identified in the children's caries lesions. All LME isolates presented important virulence traits, including biofilm formation and high acidogenicity, which cause enamel demineralization, that might increase the risk of dental caries in children carrying LME. Thus, the correct identification and in-depth virulence characterization of microorganisms isolated from dental caries are important to understand the dynamics of this disease. |
