Gabriela Ceccon Chianca

Background: For over 70 years, guidelines have recommended antibiotics for infective endocarditis (IE) prophylaxis before dental procedures, focusing on oral streptococci. Objectives: Our in silico study aimed to evaluate the potential resistance of oral streptococci against prophylactic antibiotics used before invasive dental procedures to prevent IE. Methods: The genomic assemblies and metadata of Streptococcus IE isolates were searched using specific terms in BioSample and RefSeq databases. Their antimicrobial resistance phenotypes for 91 drugs belonging to 22 different classes were predicted with ResFinder and analysed regarding the recommended IE dental prophylactic antibiotics, focusing on the oral streptococci assemblies. Results: Among the 258 Streptococcus isolates dating from 1935 to 2021 from 12 countries, 79.46% were classified as oral streptococci, and 38.37% of the 258 assemblies carried resistance genes to at least one antimicrobial. Seven isolates carried the transposon Tn6331, which can confer resistance to aminoglycosides, macrolides, lincosamides, streptogramins and tetracyclines. Within the oral Streptococcus strains, none carried resistance genes to amoxicillin, but potential resistance to azithromycin (24.88%) and doxycycline (16.59%) was observed. Conclusions: Our in silico study showed that none of the oral Streptococcus assemblies from IE carried resistance genes to the primary regimen recommended for IE prophylaxis following invasive dental procedures. However, several assemblies were potentially resistant to alternative prophylactic regimens for patients allergic to penicillin or ampicillin.

To avoid failure of endodontic treatment, it is important to properly seal the root canals after chemomechanical preparation in order to avoid microleakage. Typically, sealing involves the use of gutta‐percha and sealing cement, the latter of which adheres to the dentin and fills the spaces between the gutta‐percha and the dentin walls. Laboratory studies have been performed to detect microleakage of endodontic sealers based on various criteria, including microbiological ones; however, none guaranteed that the leakage occurred through the root canal space and not through other pathways. This article proposes a new laboratory assay to evaluate bacterial microleakage in endodontic sealers, ensuring visualization of the correct inoculum infiltration pathway. Furthermore, we present the main critical parameters and provide suggestions on how to manage them. These protocols allow the detection of bacterial microleakage in bovine teeth filled with endodontic sealer and inoculated with Enterococcus faecalis . © 2026 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1 : Bovine teeth selection and cleaning Basic Protocol 2 : Bovine teeth inclusion Basic Protocol 3 : Tooth standardization Basic Protocol 4 : Set preparation Basic Protocol 5 : Inoculum preparation Basic Protocol 6 : Canal inoculation Basic Protocol 7 : Set incubation

SignificanceDental caries is a polymicrobial condition derived from microbial biofilm. There is a lack of studies addressing antimicrobial photodynamic therapy (aPDT) activity against a cariogenic multispecies biofilm.AimWe aim to evaluate the activity of aPDT against a cariogenic biofilm composed of a microbial consortium.ApproachEqual parts of Streptococcus mutans, Lactobacillus rhamnosus, and Candida albicans were used to form a microbial inoculum containing ∼107 colony-forming units/mL, which was placed on cellulose acetate membranes to form biofilm. After biofilm formation, the seven groups, each containing four membranes, were treated as follows: laser 1 J (G1); laser 4 J (G2); photosensitizer methylene blue (G3); photosensitizer + laser 1 J (G4); photosensitizer + laser 4 J (G5); chlorhexidine as positive control (G6); and distilled water (G7).ResultsThe number of viable microbial cells per biofilm varied between 1.40×108 (G5) and 7.28×108 (G1), whereas the negative control group (G7) reached 1.38×109. Compared with G7, all groups presented a reduction, with the percentage varying from 47.05% (G1) to 89.85% (G5). However, G5 (photosensitizer + laser 4 J) was the only group to present a statistical reduction (p<0.05).ConclusionaPDT represents an important antibiofilm adjunct therapy, resulting in a significant reduction in microbial cells within a cariogenic biofilm model.

The COVID-19 pandemic and its effects on public health have urgently demanded effective health policies to avoid the spread of COVID-19. Thus, public administrators have implemented non-pharmacological and pharmacological interventions to mitigate the pandemic’s impacts and strengthen health services. The aim of this ecological study is to describe the scenario of COVID-19 pandemic in a Brazilian city, during two years. This ecological study was carried out in Nova Friburgo, a Brazilian city, for 105 weeks (two years), from March 29, 2020 (week 1) to April 02, 2022 (week 105). Data on COVID-19 cases and COVID-19 deaths, occupation of COVID-19 exclusive beds in hospitals, community mobility, vaccination, government regulation on the opening of city establishments and city risk assessment were collected from public datasets. Four waves of COVID-19 cases and deaths were observed during this period. The first case occurred in week 1 and first death in week 3 of this study. The highest peaks of cases and deaths were observed during the third wave with 1,131 cases (week 54) and 47 deaths (week 55) and where the highest occupation of COVID-19 exclusive beds in local hospitals occurred. Interventions from more restrictive to more flexible, were implemented throughout this study, including lockdown and gradual return in economic and social strata levels. Vaccination began on week 43 and at the end of this study 89.91% of the total population was vaccinated with at least one dose, being 83.22% fully vaccinated. A deep description of several interventions used to avoid COVID-19 spread in a Brazilian city during two years of this pandemic can help promote better decision-making in the future while it exposes the challenges of conducting public health policies in a pandemic scenario.

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.