In vitro bacterial adherence on teeth submitted to whitening with musa paradisiaca / Adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con musa paradisiaca

Objetive: To compare in vitro bacterial adherence on teeth submitted to whitening with 50% ethanolic extract of Musa paradisiaca and 35% hydrogen peroxide. Material and Methods: The study was experimental and used 18 premolars that were grouped into: G1 (control), G2 (50% ethanol extract of Musa paradisiaca) and G3 (35% hydrogen peroxide). The teeth were then exposed to a Streptococcus mutans culture for 24 hours, followed by centrifugation in thioglycolate broth. A culture on trypticase soy agar was done with a 1 in 100 dilution, and after 48 hours colony forming units (CFU) were counted. Statistical analysis was performed using the ANOVA test, complemented by the Bonferroni post-hoc. Results: Bacterial adherence was 77x105 CFU/ml in Group 3 using 35% hydrogen peroxide, 40x105 CFU/ml in Group 2 using 50% ethanol extract of Musa paradisiaca, and 89x104 CFU/ml in Group 1 (control). The difference between the three groups was significant (p=0.000). Conclusion: Both whitening methods cause bacterial adherence to the tooth surface, although to a lower degree with Musa paradisiaca.eses.

Objetivo: Comparar la adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con extracto etanólico de Musa paradisiaca al 50% y con peróxido de hidrógeno al 35%. Material y Métodos: Comparar la adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con extracto etanólico de Musa paradisiaca al 50% y con peróxido de hidrógeno al 35%.Resultados: La adherencia bacteriana fue de 77x105 UFC/ml con el peróxido de hidrógeno al 35%, de 40x105 UFC/ml con el extracto etanólico de Musa paradisiaca al 50% y de 89x104 UFC/ml con el control. La diferencia fue significativa entre los tres grupos (p=0.000). Conclusión: Ambos métodos de blanqueamiento causan adherencia bacteriana en la superficie dental, siendo menor con Musa paradisiaca.

Streptococcus Mutans Biofilm Influences on the Antimicrobial Properties of Glass Ionomer Cements

Abstract The aim of this study was to evaluate the in vitro antibacterial and biofilm inhibition properties of glass ionomer restorative cements. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX were analyzed using the following tests: a) agar plate diffusion test to evaluate the inhibitory activity of cements against S. mutans (n=8); b) S. mutans adherence test by counting colony-forming units after 2 h of material/bacteria exposure (n=10); c) biofilm wet weight after seven days of bacterial accumulation on material disks, with growth medium renewed every 48 h (n=10); d) pH and fluoride measurements from the medium aspired at 48 h intervals during the 7-day biofilm development (n=10). Data from the a, b and c tests were submitted to Kruskal-Wallis and Mann-Whitney tests and the fluoride-release and pH data were submitted to two-way ANOVA and Tukey tests (a=5%). Vitremer followed by Ketac Nano showed the greatest inhibitory zone against S. mutans than the conventional ionomers. Vitremer also showed higher pH values than Ketac Nano and Fuji IX in the first 48 h and released higher fluoride amount than Ketac Nano e Ketac Molar Easymix throughout the experimental period. The chemical composition of restorative glass ionomer materials influenced the antibacterial properties. The resin modified glass ionomer (Vitremer) was more effective for inhibition of S. mutans and allowed greater neutralization of the pH in the first 48 h. However, the type of glass ionomer (resin modified or conventional) did not influence the weight and adherence of the biofilm and fluoride release.

Resumo O objetivo neste estudo foi avaliar in vitro as propriedades antibacterianas e a inibição do biofilme de cimentos de ionômero de vidro restauradores. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX foram avaliados através dos seguintes testes: a) teste de difusão em ágar para avaliar a inibição de S. mutans nos cimentos (n=8); b) adesão de S. mutans pela contagem de unidades formadoras de colônia após 2h de exposição material/bactéria (n=10); c) peso do biofilme úmido após sete dias de acúmulo bacteriano nos discos do material, com meio de cultura renovado após 48 h (n=10); d) mensuração do pH e liberação de flúor do meio aspirado nos intervalos de 48 h durante 7 dias de crescimento do biofilme (n=10). Os dados dos testes a, b e c foram submetidos aos testes Kruskal-Wallis e Mann-Whitney e os dados de liberação de flúor e pH a ANOVA dois fatores e Tukey (a = 5%). Vitremer seguido pelo Ketac Nano mostrou maior zona de inibição contra S. mutans quando comparados aos ionômeros convencionais. Vitremer também apresentou valores de pH mais elevados do que Ketac Nano e Fuji IX nas primeiras 48 h e liberou maior quantidade de flúor do que Ketac Nano e Ketac Molar Easymix durante todo o período experimental. A composição química dos ionômeros de vidro restauradores influenciou nas propriedades antibacterianas. O ionômero de vidro modificado por resina (Vitremer) foi mais eficaz na inibição de S. mutans e permitiu maior neutralização do pH nas primeiras 48 h. No entanto, o tipo de ionômero de vidro (modificado por resina ou convencional) não influenciou no peso e adesão do biofilme e na liberação de flúor.

Estudo de atributos de virulência e resistência a antimicrobianos em amostras de P. aeruginosa / Study of attributes of virulence and antimicrobial resistance in P. aeruginosa isolates

P. aeruginosa é um importante agente de infecções relacionadas à assistência em saúde. Habitualmente, o estabelecimento de infecções agudas é precedido pela colonização das mucosas dos pacientes. Não se sabe, porém, se os processos infecciosos são causados pelas próprias cepas bacterianas colonizadoras ou por outras com que os pacientes entrem em contato, dotadas ou não de maior potencial de virulência ou de resistência a antimicrobianos que as tornem mais eficientes como agentes infecciosos. Assim, este estudo teve como objetivos i) investigar a existência de potenciais diferenças entre amostras de P. aeruginosa que causaram apenas colonização e aquelas responsáveis por infecção, isoladas de um mesmo paciente, quanto a seus fenótipos de virulência e de não susceptibilidade a antimicrobiamos; ii) pesquisar a existência de associação entre características dos paciente, incluindo o tipo de evolução clínica, com as demais variáveis estudadas. No estudo foram incluídos 21 pacientes que desenvolveram infecção por P. aeruginosa durante sua internação no Centro de Terapia Intensiva do Hospital Universitário Clementino Fraga Filho, entre abril de 2007 e abril de 2008. De cada paciente foram selecionadas duas amostras bacterianas: a primeira isolada durante o episódio de infecção e a amostra colonizadora obtida imediatamente antes da ocorrência da infecção. As amostras selecionadas foram estudadas quanto a i) expressão de três mecanismos de virulência (citotoxicidade, aderência a células epiteliais respiratórias humanas e capacidade de formação de biofilme); ii) presença de genes codificadores das proteínas efetoras do sistema de secreção do tipo 3 (SST3 - exoS, exoT, exoU e exoY); iii) perfil de susceptibilidade a antimicrobianos, iv) perfil de fragmentação do DNA cromossômico por eletroforese em gel de campo pulsado (PFGE). As amostras bacterianas obtidas de infecções agudas foram significativamente mais citotóxicas que aquelas obtidas de colonização...

P. aeruginosa is an important agent of healthcare-associated infections. The establishment of acute infectious episodes is usually preceded by colonization of patient mucosa. However, it remains unknown whether the infectious processes are caused by bacterial strains previously colonizing the patient or by additional strains the patient may come into contact. These new isolates may carry greater virulence potential or antibiotic resistance that makes them more efficient as an infecting agent. Thus, the objetives of the present study were i) to investigate the existence of potential differences between P. aeruginosa isolates obtained from a colonized mucosa and isolates accounting for infectious processes, recovered from the same patient, with respect to virulence phenotypes and non-susceptibility to antimicrobial agents; ii) to investigate the existence of association between patient features, including the type of clinical outcome, with bacterial characteristics. The study included 21 patients who developed P. aeruginosa infection during their stay in the Intensive Care Unit of the University Hospital Clementino Fraga Filho, from April 2007 to April 2008. Two P. aeruginosa isolates were selected from each patient: the first isolate recovered from the infectious episode and the colonizing isolate obtained immediately before the onset of the infection. Features from the isolates investigated included: i) expression of three virulence mechanisms (cytotoxicity, adherence to human respiratory epithelial cells and biofilm formation); ii) presence of the genes encoding type III secretion system effector proteins (TTSS, exoS , exoT , exoU and exoY); iii) antimicrobial susceptibility profile; iv) profile of the bacterial chromossomic DNA fragmentation following analysis by pulsed-field gel electrophoresis (PFGE). The bacterial isolates obtained from acute infections were significantly more cytotoxic than colonizing strains...

Bacterial Adherence to Intraocular Lenses

Bacterial adherence to intraocular lenses (IOLs)could be the cause of the endophthalmitis following cataract surgery and IOL implantation. In this study we investigated bacterial adherences to the four different IOLs. Clinical strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa were used.Polymethylmethacrylate (PMMA), silicone, hydrophilic acrylate (Acrysof)and hydrogel IOLs were used in this study.Four types of lenses were suspended for 60 minutes in suspensions of each strain of bacteria and then these lenses were washed with sterile broth to remove the nonadherent bacteria.The adherent bacteria were removed from the lenses, diluted with sterile broth and inoculated onto the blood and chocolate agar plates.The plates were incubated for 24 hours, and the numbers of colony forming units were counted. The lenses with the adherence of S.aureus in order of decreasing magnitude were: Acrysof>silicone>hydrogel>PMMA; the adherence of S.epider-midis, silicone>Acrysof>PMMA>hydrogel;the adherence of P.aeruginosa, Acrysof>silicone>PMMA>hydrogel. The bacterial adherence was significantly lower in the hydrophilic IOL.This result suggests that the risk of postoperative endophthalmitis after cataract extraction and IOL implantation may be reduced with the use of hydrophilic IOL.

Influence of Type of Screw on the Bacterial Adherence and Infection / 대한정형외과학회잡지

The purpose of the study was to evaluate the effect of commonly used orthopaedic material, stainless steel (SS) screw (2.7xlOmm, Synthes) and titanium (Ti) screw (2.7x10mm, Synthes), on bacterial adherence and infection. The bacteria used for this study was Staphylococcus epidermidis for its ability of adherence. For in vitro assay, screws of each material were placed into test tube containing 107 colony forming unit (CFU) of S. epidermidis in trypticase soy broth for 18 hours. Following incubation, each screws were treated either with trypsin or with an ultrasonic cleaner. For in vivo assay, we inoculated 5x107 CFU of S. epidermidis into the proximal tibial metaphysis of the rabbits, and then inserted Ti screw on the right side and SS screw on the left side. The amount of in vitro adherence of S. epidermidis was greater for SS screw than for Ti screw. Especially following trypsin treatment, SS groups yielded significantly higher bacterial counts than Ti group, respectively (1.4x105 CFU vs 2.8x104 CFU, p<0.05). We found a significantly higher bacterial count after use of SS screw than after Ti screw in rabbits in vivo assay also. Trypsin treatment for identifying biofilm embedded bacteria from implanted metal may be useful in the diagnosis of infection. Ti screw appears to have biocompatibility to inhibit bacterial adherence compared with SS screw in the rabbit tibial model.

Bacterial Adherence to Human Buccal Epitheliald Cells and Its Possible Role in Bacterial Colonization in Human Oral Cavity

The ability of several species of streptococcus and staphylococcus to adhere to human buccal epithelial cells was studied in vitro by using bacteria and epithelial cells isolated from human buccal cavity. Viridans streptococci were found adhering in highest numbers(65 +/- 8 bacteria per epithelial cell) to epithelial cells. Streptococcus pyogenes adhered in great numbers (44 +/- 4), whereas Streptococcus pneumoniae (26 +/- 2), Staphylococcus aureus (21 +/- 2), Staphylococcus epidermidis (14 +/- 2) adhered poorly. These data showed that bacteria differed in their ability to adhere to human buccal epithelial cells. This difference in adhesive ability between bacterial species may correlate with the ability of the bacteria to colonize oral surface of human.