Two years of COVID-19 pandemic: Framework of health interventions in a Brazilian city.

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 2 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 2 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.

Virulence of Lactobacillus spp. misidentified as Enterococcus faecalis from children's carious dentine.

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.

COVID-19: An Alert to Ventilator-Associated Bacterial Pneumonia.

This manuscript aims to highlight the risk of Ventilator-Associated Bacterial Pneumonia (VAP) in COVID-19 inpatients. The co-infection has the potential to worsen clinical condition and increase mortality in these patients, as well as to prolong and increase the costs of hospitalization. Preventing, identifying and treating early VAP can increase the chances of successful treatment in patients with COVID-19.

The effect of a chemomechanical protocol to eliminate microorganisms from pulpectomized primary teeth: three case reports

Introduction: Description of the bacterial community before and after chemomechanical preparation (CP) with the removal of a smear layer (SL) in pulpectomized primary teeth has been little reported. Objective: These case reports describe the presence of total microorganisms and Enterococcus faecalis in root canals of primary incisors before and after CP with SL removal. Case Reports: Microbiological samples were collected from the root canals of three children (3.66±0.58 years old) with necrosis (n=2) and irreversible pulpal inflammation (n=1) in maxillary primary incisors. After teeth isolation with a rubber dam and antisepsis of the operative field, the sample collections were performed with sterile absorbent paper cones before and after the CP, which included irrigation with 2.5% sodium hypochlorite followed by 6% citric acid to remove the SL. The collected samples were analysed immediately at the end of the clinical procedures. The plates were incubated anaerobically for 48 hours at 37°C. The results were expressed as colony forming units (CFU)/mL. Results: Two of the three teeth showed total microorganisms before the CP. One incisor had no microorganisms in the initial collection. No CFU was counted in the samples collected after CP. Moreover, E. faecalis was not observed any time, either before or after the CP. Conclusions: E. faecalis was not detected in any sample, yet two of the three root canals had microorganisms before CP. In cases where microorganisms were initially found, 100% elimination was observed after the applied protocol.

Introdução: A descrição da comunidade bacteriana antes e após o preparo químico-mecânico (PQM) com remoção da smear layer (SL) em dentes decíduos pulpectomizados tem sido pouco relatada. Objetivo: Esses relatos de casos descrevem a presença de microrganismos totais e Enterococcus faecalis em canais radiculares de incisivos decíduos antes e após PQM com remoção de SL. Relatos dos Casos: Amostras microbiológicas foram coletadas do canal radicular de três crianças (3,66 ± 0,58 anos) com necrose (n = 2) e inflamação pulpar irreversível (n= 1) em incisivos decíduos superiores. Após o isolamento dos dentes com dique de borracha e antissepsia do campo operatório, as coletas das amostras foram realizadas com cones de papel absorvente estéril antes e após o PQM, que incluiu irrigação com hipoclorito de sódio 2,5% seguido de ácido cítrico 6% para retirada do SL. As amostras coletadas foram analisadas imediatamente ao final dos procedimentos clínicos. As placas foram incubadas em anaerobiose durante 48 horas a 37°C. Os resultados foram expressos em unidades formadoras de colônias (UFC)/mL. Resultados: Dois dos três dentes apresentaram microrganismos totais antes do PQM. Um incisivo não apresentava microrganismos na coleta inicial. Nenhuma UFC foi contada nas amostras coletadas após o PQM. Além disso, o E. faecalis não foi observado nenhum momento, nem antes, nem depois do PQM. Conclusão: Não foi detectado E. faecalis em nenhuma amostra, porém dois dos três canais radiculares apresentavam microrganismos antes do PQM. Nos casos em que foram encontrados microrganismos inicialmente, observou-se 100% de eliminação após o protocolo aplicado.

Is Antimicrobial Photodynamic Therapy Effective for Microbial Load Reduction in Peri-implantitis Treatment? A Systematic Review and Meta-Analysis.

The systematic review and meta-analysis were undertaken to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) in the microbiological alteration beneficial to peri-implantitis treatment. This study is registered with PROSPERO, number CRD42017064215. Bibliographic databases including Cochrane Library, Web of Science, Scopus and PubMed were searched from inception to 8 January 2017. The search strategy was assembled from the following MeSH Terms: "Photochemotherapy," "Dental Implants" and "Peri-Implantitis." Unspecific free-text words and related terms were also included. The Cochrane Collaboration's tool was used to evaluate the risk of bias of included studies. The random-effect model was chosen, and heterogeneity was evaluated using the I2 test. Three studies met the inclusion criteria. Meta-analysis demonstrated an association between aPDT and reduction in viable bacteria counts for: Aggregatibacter actinomycetemcomitans (OR = 1.31; confidence interval = 1.13, 1.49; P < 0.00001), Porphyromonas gingivalis (OR = 4.08; confidence interval = 3.22, 4.94; P < 0.00001) and Prevotella intermedia (OR = 1.66; confidence interval = 1.06, 2.26; P < 0.00001). A aPDT appears to be effective in bacterial load reduction in peri-implantitis and has a positive potential as an alternative therapy for peri-implantitis.

Influence of thickness, color, and polishing process of ethylene-vinyl-acetate sheets on surface roughness and microorganism adhesion.

BACKGROUND/AIM: The surface roughness of dental materials can make cleaning difficult, thus facilitating retention of food debris and accumulation of microorganisms. The aim of this study was to assess whether thickness, color, and the polishing process influence the surface roughness of ethylene-vinyl-acetate (EVA) sheets and the amount of microorganisms that adhere to them. MATERIALS AND METHODS: A total of 180 samples of EVA (5 × 5 mm) were divided into 9 groups according to thickness (G1 = 2 mm; G2 = 3 mm; and G3 = 4 mm), color (G4 = black and G5 = white), and type of polishing (G6 = Scheu™; G7 = Scheu™ associated with hot-air burner; G8 = Erkodent™ and G9 = Erkodent™ associated with hot-air burner). Mean value of 3 roughness parameters was assessed: Ra, Rq, and Rz (one-way ANOVA test and Tukey's test, P < .05). Seven samples of each group (n = 63) were inoculated with saliva for 2 hours to promote microbial adhesion and count the number of colony-forming units (CFUs) (one-way ANOVA test, P < .05). Scanning electron microscopy (SEM) of microbial adhesion and the effects of the polishing process on the surface was assessed. RESULTS: Only the polishing parameter presented less roughness (G2, G7 and G9; P < .05) as also observed on SEM. SEM characterized microbial adhesion but the CFU count was not statistically significant, independent of the assessed parameters. CONCLUSION: The polishing systems, Scheu™ and Erkodent™ in association with a hot-air burner, were effective in decreasing the surface roughness without influencing the amount of adhered microorganisms.

Use of antimicrobial photodynamic therapy for treatment of deep caries in the primary dentition: a step-by-step technique report.

Antimicrobial photodynamic therapy (aPDT) is increasingly used in dentistry to treat a number of diseases. The procedure involves the activation of a photosensitizer by a visible light source to induce chemical reactions that create cytotoxic reactive oxygen species, cause oxidative stress, and result in inactivation of pathogenic microorganisms. The use of aPDT has been proven to reduce microorganisms present in dentin and therefore may be effective for treatment of deep caries. This case report describes the use of aPDT as an adjuvant therapy in the treatment of deep caries in the primary molar of a 7-year-old boy. The case also highlights the preservation of pulpal vitality-in accordance with the concepts of minimal intervention-as well as the reduction of chair time achieved by resolving the case in a single session, a factor that is important for the treatment of children.

Methicillin resistance and virulence genes in invasive and nasal Staphylococcus epidermidis isolates from neonates.

BACKGROUND: Staphylococcus epidermidis is an opportunistic pathogen involved in hospital-acquired infections, particularly in those related to medical devices. This study characterized 50 genetically unrelated S. epidermidis isolates from bloodstream infections (BSIs, n = 31) and nares (n = 19) of neonates in relation to staphylococcal chromosomal cassette mec (SCCmec) type, biofilm production and associated genes, and the arginine catabolic mobile elements (ACME), in order to detect virulence factors that could discriminate a potential invasiveness isolate or predict an increasing pathogenicity. RESULTS: Isolates from both groups showed no difference for biofilm production and ACME genes detection. However, BSI isolates harbored more frequently the sdrF and sesI genes (p < 0.05), whereas biofilm producer isolates were associated with presence of the aap gene. The sdrF gene was also significantly more in the biofilm producer isolates from BSI. The SCCmec type IV and the ccr2 complex were related to BSI isolates (p < 0.05), while 83% of the nasal isolates were non-typeable for the SCCmec elements, with the mec complex and ccr undetectable as the most frequent profile. CONCLUSIONS: Despite the great clonal diversity displayed by S. epidermidis isolates from neonates, BSI isolates harbored more frequently the sdrF and sesI adhesin genes, while nasal isolates were very variable in SCCmec composition. These aspects could be advantageous to improve colonization in the host increasing its pathogenicity.

Antibacterial Activity of Melaleuca alternifolia (tea tree essential oil) on Bacteria of the Dental Biofilm

Objective: To evaluate the antibacterial activity of tea tree EO on Streptococcus mutans (ATCC 25175), S. salivarius (ATCC 7073) and Lactobacillus rhaminosus (ATCC 9595). Material and Methods: The antibacterial activity of M. alternifolia EO was evaluated by the broth dilution method, by which minimum inhibitory and bactericidal concentrations (MIC and MBC) were determined. Serial dilutions range from 70243.90 µg/mL to 26.14 µg/mL. The MIC evaluation was performed in 96-well microplates, in which 100 µL of Brain Heart Infusion (BHI), 100 µL of the EO dilution and 5 µL of the inoculum (final concentration = 5x105 CFU/mL) were inserted. After 24 h of incubation, MIC was determined as the lowest concentration capable of inhibiting microbial growth, identified by the resazurin reaction (100 µg/mL). CBM was identified by the absence of subculture growths (50 µL) of dilutions equal to or greater than MIC. Tests were performed in triplicate and at three different times (n = 9). Pharmacological controls (0.05% and 0.12% Chlorhexidine), growth and sterility were used to validate the results. Results: The MIC of M. alternifolia compared to S. mutans, S. salivarius and L. rhaminosus was 1940.16 µg/mL, 3977.34 µg/mL and 3977.34 µg/mL, respectively. The MBC values were 70243.90 µg/mL, 3977.34 µg/mL and 34265.31 µg/mL, respectively. Conclusion: The essential oil of M. alternifolia presented antibacterial activity against the microorganisms evaluated when in high concentration.

Effect of the antimicrobial photodynamic therapy on microorganism reduction in deep caries lesions: a systematic review and meta-analysis.

This study aimed to perform a systematic review to assess the effectiveness of antimicrobial photodynamic therapy (aPDT) in the reduction of microorganisms in deep carious lesions. An electronic search was conducted in Pubmed, Web of Science, Scopus, Lilacs, and Cochrane Library, followed by a manual search. The MeSH terms, MeSH synonyms, related terms, and free terms were used in the search. As eligibility criteria, only clinical studies were included. Initially, 227 articles were identified in the electronic search, and 152 studies remained after analysis and exclusion of the duplicated studies; 6 remained after application of the eligibility criteria; and 3 additional studies were found in the manual search. After access to the full articles, three were excluded, leaving six for evaluation by the criteria of the Cochrane Collaboration's tool for assessing risk of bias. Of these, five had some risk of punctuated bias. All results from the selected studies showed a significant reduction of microorganisms in deep carious lesions for both primary and permanent teeth. The meta-analysis demonstrated a significant reduction in microorganism counts in all analyses (p<0.00001). Based on these findings, there is scientific evidence emphasizing the effectiveness of aPDT in reducing microorganisms in deep carious lesions.

Molecular Markers of Antimicrobial Resistance in Methicillin-Resistant Staphylococcus aureus SCCmec IV Presenting Different Genetic Backgrounds.

Methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec type IV has emerged in hospitals worldwide. The aim of this study was to evaluate phenotypic and molecular characteristics of antimicrobial resistance in MRSA SCCmec IV isolates, presenting different genetic backgrounds, isolated from hospitals in Rio de Janeiro. The antimicrobial resistance of 128 S. aureus type IV isolates from 11 hospitals was characterized by the disk diffusion test and minimum inhibitory concentration (MIC) test. Mutations in parC gene, which encodes ciprofloxacin resistance, and genes associated with macrolide-lincosamide-streptogramin B (MLSb) resistance were also investigated. MRSA isolates belonging to USA400/ST1 (60 isolates), USA800/ST5 (40), USA1100/ST30 (13), and other 11 (15) lineages were mainly resistant to erythromycin (68%), ciprofloxacin (56%), and clindamycin (50%). The highest antimicrobial resistance rates were found among USA400 isolates (p < 0.05). The majority of them (90%) carried only the erm(C) gene and mainly presented two mutation types in the parC gene. The msr(A) gene was most frequently found among USA800 isolates (p < 0.05). Among MRSA type IV isolates from Rio de Janeiro hospitals, multiresistance, including mutations in parC gene, was associated to the USA400/ST1, while the msr(A) gene was associated with USA800/ST5 isolates, highlighting that these lineages could have more potential to persist in a hospital environment.

Influence of a Brazilian wild green propolis on the enamel mineral loss and Streptococcus mutans' count in dental biofilm.

OBJECTIVE: This study investigated the anti-demineralizing and antibacterial effects of a propolis ethanolic extract (EEP) against Streptococcus mutans dental biofilm. DESIGN: Blocks of sound bovine enamel (n=24) were fixed on polystyrene plates. S. mutans inoculum (ATCC 25175) and culture media were added (48 h-37 °C) to form biofilm. Blocks with biofilm received daily treatment (30 µL/1 min), for 5 days, as following: G1 (EEP 33.3%); G2 (chlorhexidine digluconate 0.12%); G3 (ethanol 80%); and G4 (Milli-Q water). G5 and G6 were blocks without biofilm that received only EEP and Milli-Q water, respectively. Final surface hardness was evaluated and the percentage of hardness loss (%HL) was calculated. The EEP extract pH and total solids were determined. S. mutans count was expressed by log10 scale of Colony-Forming Units (CFU/mL). One way ANOVA was used to compare results which differed at a 95% significance level. RESULTS: G2 presented the lowest average %HL value (68.44% ± 12.98) (p=0.010), while G4 presented the highest (90.49% ± 5.38%HL) (p=0.007). G1 showed %HL (84.41% ± 2.77) similar to G3 (87.80% ± 6.89) (p=0.477). Groups G5 and G6 presented %HL=16.11% ± 7.92 and 20.55% ± 10.65; respectively (p=0.952). G1 and G4 differed as regards to S. mutans count: 7.26 ± 0.08 and 8.29 ± 0.17 CFU/mL, respectively (p=0.001). The lowest bacterial count was observed in chlorhexidine group (G2=6.79 ± 0.10 CFU/mL) (p=0.043). There was no difference between S. mutans count of G3 and G4 (p=0.435). The EEP showed pH 4.8 and total soluble solids content=25.9 Brix. CONCLUSION: The EEP seems to be a potent antibacterial substance against S. mutans dental biofilm, but presented no inhibitory action on the de-remineralization of caries process.

Molecular characterization of Staphylococcus aureus isolates carrying the Panton-Valentine leukocidin genes from Rio de Janeiro hospitals.

In a collection of 50 pvl-positive Staphylococcus aureus isolates from 10 Rio de Janeiro hospitals, 18 (36%) were from bloodstream infections, and 31 (62%) carried the SCCmec IV. Among 25 (50%) isolates of the USA1100/ST30/CC30 lineage present in 8 hospitals, 1 isolate was characterized as vancomycin-intermediate S. aureus.

Does the presence of sucrose in pediatric antibiotics influence the enamel mineral loss and the Streptococcus mutans counts in dental biofilm?

The role of antibiotics containing sucrose on the formation of dental caries is still controversial. This study aimed to investigate the effect of two antibiotics (amoxicillin and potassium clavulanate suspension), with and without sucrose, on human dental hardness and Streptococcus mutans counts in dental biofilm. Primary tooth fragments (n=72) were coated with nail varnish leaving a window of 2.25 mm diameter. Specimens were fixed in 24-well polystyrene plates, containing BHI medium. S. mutans (clinical strains) represented the inoculum to form biofilm on the fragments for 24 h. Twelve fragments were separated for the initial count of microorganisms (baseline). The other fragments were divided into 4 groups (n=12) of treatment: G1 (Clavulin(r)), G2 (Betamox(r)), G3 (chlorhexidine 0.12%), G4 (sucrose 10%). All specimens had their self-control area (covered area). The cross-sectional microhardness (CSMH) was evaluated for each specimen. All the treated groups had a loss of hardness compared to their self-controls (p<0.05). Both drugs inhibited the S. mutans growth and promoted no CSMH difference among them. Both antibiotics eliminated all formed biofilm and did not cause mineral loss from the enamel, regardless the presence of sucrose in its formulation.

Does the Presence of Sucrose in Pediatric Antibiotics Influence the Enamel Mineral Loss and the Streptococcus mutans Counts in Dental Biofilm?

The role of antibiotics containing sucrose on the formation of dental caries is still controversial. This study aimed to investigate the effect of two antibiotics (amoxicillin and potassium clavulanate suspension), with and without sucrose, on human dental hardness and Streptococcus mutans counts in dental biofilm. Primary tooth fragments (n=72) were coated with nail varnish leaving a window of 2.25 mm diameter. Specimens were fixed in 24-well polystyrene plates, containing BHI medium. S. mutans (clinical strains) represented the inoculum to form biofilm on the fragments for 24 h. Twelve fragments were separated for the initial count of microorganisms (baseline). The other fragments were divided into 4 groups (n=12) of treatment: G1 (Clavulin(r)), G2 (Betamox(r)), G3 (chlorhexidine 0.12%), G4 (sucrose 10%). All specimens had their self-control area (covered area). The cross-sectional microhardness (CSMH) was evaluated for each specimen. All the treated groups had a loss of hardness compared to their self-controls (p<0.05). Both drugs inhibited the S. mutans growth and promoted no CSMH difference among them. Both antibiotics eliminated all formed biofilm and did not cause mineral loss from the enamel, regardless the presence of sucrose in its formulation.

O papel dos antibióticos contendo sacarose na formação de cárie dentária é ainda controverso. Este estudo teve como objetivo investigar o efeito de dois antibióticos (amoxicilina / clavulanato de potássio suspensão oral), com e sem sacarose, na dureza do esmalte dental humano e na contagem de Streptococcus mutans no biofilme dental. Fragmentos de dentes decíduos (n = 72) foram revestidos com verniz deixando uma janela de exposição de 2,25mm de diâmetro. Os espécimes foram fixados em placas de poliestireno de 24 poços, contendo meio de cultura BHI. S. mutans (estirpes clínicas) representaram o inoculo para formar biofilmes sobre os fragmentos por 24 h. Doze fragmentos foram separados para a contagem inicial de microrganismos (baseline). Os restantes dos fragmentos foram divididos em 4 grupos (n = 12) de tratamento: G1 (Clavulin(r)), G2 (Betamox(r)), G3 (clorexidina 0,12%), G4 (sacarose a 10%). Todas as amostras tiveram sua área de controle (área coberta). A microdureza transversal (CSMH) foi avaliada para cada espécime. Todos os grupos tratados tiveram uma perda de dureza quando comparados com os seus respectivos controles (p <0,05). Ambos os fármacos inibiram o crescimento de S. mutans e não promoveram diferença da CSMH entre eles. Ambos os antibióticos eliminaram todo o biofilme formado, não promovendo assim, perda mineral do esmalte, independente da presença de sacarose na sua formulação.

Oral bacteria adherence to suture threads: an in vitro study.

PURPOSE: This study investigated the adherence of oral microorganisms to different types of suture threads. METHODS: Pieces of thread were distributed on 24-well plates, according to the following groups: (G1) nylon, (G2) silk, (G3) polyglactin 910, (G4) polyglactin 910 with triclosan. Blank control (G5) consisted of one thread from each group. Adherence to thread tests was performed to observe adhesion of total microorganisms from saliva or two isolates of Prevotella intermedia (ATCC49046) and Fusobacterium nucleatum (ATCC51190). Brain-heart infusion (BHI) medium with or without bacterial inoculum (1.8 × 10(7) CFU/mL) was added to each well of microplates. The microplates were incubated in an anaerobic chamber at 37 °C, for 5 days for biofilm formation. RESULTS: There was no difference between the groups as regard to adhesion of F. nucleatum (p > 0.05). For P. intermedia, the threads in G1 and G4 showed a lower level of adhesion (p < 0.05), with no difference between them. Against total microorganisms, G1 presented a lower level of adherence (p < 0.05), followed by G4; and no difference was observed between G2 and G3. CONCLUSIONS: Total microorganisms and P. intermedia have different affinities to the tested suture threads, whereas F. nucleatum presented a similar adherence level. Among the threads, nylon (G1), followed by polyglactin 910 with triclosan (G4) presented the lowest microbial adherence level.

Linezolid-resistant Staphylococcus haemolyticus and Staphylococcus hominis: single and double mutations at the domain V of 23S rRNA among isolates from a Rio de Janeiro hospital.

In this work, the molecular and phenotypic antimicrobial resistance and clonal diversity of 10 linezolid-resistant Staphylococcus spp. isolates were investigated. The 7 Staphylococcus haemolyticus isolates presented Staphylococcal cassete chromosome mec (SCCmec) V and belonged to the same pulsed-field gel electrophoresis pulsotype. Their MICs for oxacillin, vancomycin, and linezolid were ≥ 256 µg/mL, 1-4 µg/mL, and 8-16 µg/mL, respectively. The 3 S. hominis presented MIC values 32 to >256 µg/mL, 2-4 µg/mL, and 12-24 µg/mL, and all carried the nontypeable SCCmec (ccr1 + mecA class) and belonged to 2 different genotypes. The cfr gene was not found, but the mutation G2603T was detected in S. haemolyticus and C2190T and G2603T in Staphylococcus hominis in 23S rRNA. This study demonstrates the spread of a linezolid-resistant S. haemolyticus genotype and, for the first time, describes the mutation C2190T among S. hominis isolates with a double mutation in Brazil.

Staphylococcal cassette chromosome mec elements in methicillin-resistant coagulase-negative staphylococci from a Brazilian neonatal care unit.

To characterize 46 methicillin-resistant coagulase-negative staphylococci from Brazilian neonates, we investigated their SCCmec type, susceptibility and clonality. Staphylococcus epidermidis and Staphylococcus haemolyticus were the prevalent species. SCCmec types III or IV were detected in 53.3% S. epidermidis, whereas 63.6% S. haemolyticus were nontypeable. Despite the diversity, specific clones carried specific SCCmec elements, highlighting that effective typing can help in epidemiological analysis.

Effect of a sugar-free pediatric antibiotic on primary tooth enamel hardness when exposed to different sucrose exposure conditions in situ.

OBJECTIVES: This in situ study aimed to investigate the effect of a sugar-free antibiotic suspension containing amoxicillin and clavulanic acid on enamel hardness of human primary teeth simulating different conditions of cariogenic challenge. MATERIALS AND METHODS: A crossover, partially double-blind study was conducted in three phases of 14 days each, during which 11 volunteers wore palatal devices containing six dental enamel blocks covered with plastic meshes to allow biofilm formation. Dental blocks were extraorally submitted to treatment with a 20 % sucrose solution at three different daily frequencies of exposure (0, 3, and 8 times/day), and to the antibiotic suspension or its excipients at an 8-h time interval application regimen. On the 14th day of each phase, the blocks were removed for enamel analysis (surface and cross-sectional microhardness--SMH and CSMH). RESULTS: The antibiotic suspension showed significant higher SMH and CSMH values than the excipients (p < 0.05; Wilcoxon), regardless of the frequency of sucrose exposure. Sucrose exposure did not account for further enamel demineralization both for antibiotic and excipients (p > 0.05; Friedman). CONCLUSIONS: A protective effect of the antibiotic suspension on enamel demineralization was verified because its excipients alone promoted more pronounced surface and subsurface enamel demineralization, even in the absence of sucrose exposure. CLINICAL RELEVANCE: The use of a sugar-free amoxicillin/clavulanic acid suspension may promote a protective effect on primary enamel demineralization probably due to its topical effect on dental biofilm.

In vitro effect of paediatric liquid medicines on deciduous enamel exposed to biofilm.

OBJECTIVE: This study aimed to assess the in vitro effects of paediatric liquid medicines on deciduous enamel exposed to biofilms. METHODS: Fragments (n = 25) of first primary molars were covered by nail varnish, leaving a 22 mm(2) exposure area. Specimens were fixed in polystyrene plates containing BHI broth media. Pooled human saliva was added to form a mature biofilm on fragments over a 10-day period in microaerophilic conditions. Specimens were divided into groups (n = 5 per group) and treated (50 µL) daily for 1 min over 1 week as follows: G1 = 10% sucrose solution (positive control); G2 = Dimetapp Elixir® (antihistamine); G3 = Claritin® (antihistamine); and G4 = Klaricid® (antibiotic). Five other fragments, without treatment and inoculum represented the blank controls. The covered area for each specimen represented the negative control. Cross-sectional hardness of the enamel was used as a demineralization indicator. RESULTS: All treatment groups showed hardness loss compared to the corresponding negative controls (p < 0.05). Among the treatment groups, G2 exhibited the greatest demineralization pattern (p < 0.05) followed by G3, G1 and G4. CONCLUSION: All medicines caused deciduous enamel demineralization in the presence of biofilm. The greatest hardness loss was observed after treatment with Dimetapp Elixir®.