Serotipos prevalentes de Streptococcus mutans en América Latina / Prevalent serotypes of Streptococcus mutans in Latin America

La microbiota oral está conformada por diversas especies bacterianas que en condiciones normales desempeñan una función protectora del huésped; sin embargo, cuando existe un desequilibrio en el ecosistema, estos microorganismos son capaces de producir diversas manifestaciones como lo es el caso de la caries dental, enfermedad infecciosa producida principalmente por Streptococcus mutans, patógeno capaz de desmineralizar los tejidos duros del diente mediante la fermentación de hidratos de carbono obtenidos de la dieta. Se ha identificado en la pared celular de este microorganismo ocho serotipos que intervienen en la adhesión, agregación y coagregación bacteriana. En los seres humanos S. mutans presenta los serotipos c, e y f, siendo el serotipo c el más prevalente a nivel mundial, el cual se conoce que está asociado a pacientes sanos, a diferencia del e y f que son capaces de invadir las células endoteliales de las arterias coronarias. No obstante, en los últimos años se ha logrado identificar el serotipo k que de igual manera presenta alta capacidad de invadir el endotelio humano, actuando en la patogénesis de las enfermedades cardiovasculares. El objetivo de la presente revisión bibliográfica es lograr cuantificar los serotipos prevalentes de S. mutans en América Latina (AU)

The oral microbiota is made up of various bacterial species that under normal conditions perform a protective function of the host, however, when there is an imbalance in the ecosystem, these microorganisms are capable of producing various manifestations such as caries, an infectious disease. produced mainly by Streptococcus mutans, a pathogen capable of demineralizing the hard tissues of the tooth through the fermentation of carbohydrates obtained from the diet. Eight serotypes involved in bacterial adhesion, aggregation and coaggregation have been identified in the cell wall of this microorganism. In humans, S. mutans presents serotypes c, e, and f, serotype c being the most prevalent worldwide, which is known to be associated with healthy patients, unlike e and f, which are capable of invading the endothelial cells of the coronary arteries. However, in recent years it has been possible to identify serotype k, which also has a high capacity to invade the human endothelium, acting in the pathogenesis of cardiovascular diseases. The objective of this literature review is to quantify the prevalent serotypes of S. mutans in Latin America (AU)

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.

Antiadhesion and antibiofilm potential of Fagonia indica from Cholistan desert against clinical multidrug resistant bacteria / Potencial de antiadesão e antibiofilme de Fagonia indica do deserto do Cholistão contra bactérias multirresistentes clínicas

High resistance to antimicrobials is associated with biofilm formation responsible for infectious microbes to withstand severe conditions. Therefore, new alternatives are necessary as biofilm inhibitors to control infections. In this study, the antimicrobial and antibiofilm activities of Fagonia indica extracts were evaluated against MDR clinical isolates. The extract exhibited its antibiofilm effect by altering adherence and disintegration of bacterial cell wall. Fagonia indica has antibacterial effect as minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg mL-1 and minimum bactericidal concentration (MBC) value was 500-3000 µg mL-¹ against multidrug resistant (MDR) clinical isolates. The extract exhibited its antibiofilm effect by altering adherence and disintegration of bacterial cell wall. Fagonia indica had antibacterial effect as minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg mL-¹ and minimum bactericidal concentration (MBC) value was 500-3000 µg mL-¹ against MDR isolates. The maximum inhibitory effects of Fagonia indica chloroform extract on biofilm formation was observed on Staphylococcus aureus (71.84%) followed by Klebsiella pneumoniae (70.83%) after 48 hrs showing that inhibition is also time dependent. Our results about bacterial cell protein leakage indicated that MDR isolates treated with chloroform extract of Fagonia indica showed maximum protein leakage of K. pneumoniae (59.14 µg mL-¹) followed by S. aureus (56.7 µg mL-1). Cell attachment assays indicated that chloroform extract resulted in a 43.5-53.5% inhibition of cell adherence to a polystyrene surface. Our results revealed that extracts of Fagonia indica significantly inhibited biofilm formation among MDR clinical isolates, therefore, could be applied as antimicrobial agents and cost effective biofilm inhibitor against these MDR isolates.

A alta resistência aos antimicrobianos está associada à formação de biofilme responsável por micróbios infecciosos para suportar condições severas. Portanto, novas alternativas são necessárias como inibidores de biofilme para controlar infecções. Neste estudo, as atividades antimicrobiana e antibiofilme dos extratos de Fagonia indica foram avaliadas contra isolados clínicos MDR. O extrato exibiu seu efeito antibiofilme ao alterar a aderência e a desintegração da parede celular bacteriana. Fagonia indica tem efeito antibacteriano com valores de concentração inibitória mínima (CIM) variando de 125 a 500 µg mL-¹, e valor de concentração bactericida mínima (MBC) de 500-3000 µg mL-1 contra isolados clínicos multirresistentes (MDR). O extrato exibiu seu efeito antibiofilme ao alterar a aderência e a desintegração da parede celular bacteriana. Fagonia indica teve efeito antibacteriano com valores de concentração inibitória mínima (CIM) variando de 125 a 500 µg mL-¹, e concentração bactericida mínima (MBC) de 500-3000 µg mL-¹ contra isolados MDR. Os efeitos inibitórios máximos do extrato de clorofórmio Fagonia indica na formação de biofilme foi observada em Staphylococcus aureus (71,84%), seguido por Klebsiella pneumoniae (70,83%) após 48 horas, mostrando que a inibição também é dependente do tempo. Nossos resultados sobre extravasamento de proteínas de células bacterianas indicaram que isolados MDR tratados com extrato clorofórmico de Fagonia indica apresentaram vazamento máximo de proteínas de K. pneumoniae (59,14 µg mL-¹), seguido por S. aureus(56,7 µg mL-¹). Ensaios de fixação de células indicaram que o extrato de clorofórmio resultou em uma inibição de 43,5-53,5% da aderência das células a uma superfície de poliestireno. Nossos resultados revelaram que extratos de Fagonia indica inibiram [...].

Tumor de colon como hallazgo incidental en un paciente con endocarditis por Streptococcus gallolyticus: experiencia desde la práctica clínica / Colon tumor as an incidental finding in a patient with endocarditis due to Streptococcus gallolyticus: experience from clinical practice

El Streptococcus gallolyticus del colon. La fisiopatología que explica este fenómeno implica el aumento local de niveles de lactato puede presentarse como el germen causal de la endocarditis infecciosa en pacientes con lesiones premalignas y malignas, colágeno, fibrinógeno y fibronectina secundario a la hiperactividad metabólica tumoral que genera un ambiente adecuado para el crecimiento y adhesión bacteriana a la pared intestinal y posterior translocación al torrente sanguíneo. Simultáneamente, se establece la presencia de infecciones secundarias por la formación de biofilms, tanto a nivel colorrectal como en válvulas cardíacas. El objetivo del manuscrito es un mapeo en la literatura médica disponible sobre la correlación entre la endocarditis por Streptococcus gallolyticus y las lesiones premalignas y malignas de colon. Simultáneamente, exponer la experiencia clínica de un hombre de 82 años con diagnóstico de endocarditis por Streptococcus gallolyticus y el hallazgo incidental de pólipos adenomatosos del colon(AU)

Streptococcus gallolyticus can present as the causative germ of infective endocarditis in patients with premalignant and malignant lesions of the colon. The pathophysiology that explains this phenomenon involves the local increase in lactate that can be presented as the causal germ of infective endocarditis in patients with premalignant and malignant lesions, collagen, fibrinogen, and fibronectin levels secondary to tumor metabolic hyperactivity, which generates a suitable environment for bacterial growth and adhesion to the intestinal wall and subsequent translocation to the bloodstream. Simultaneously, the presence of secondary infections is established due to the formation of biofilms, both at the colorectal level and in the heart valves. The objective of the manuscript is a mapping in the available medical literature on the correlation between Streptococcus gallolyticus endocarditis and premalignant and malignant colonic lesions. Simultaneously, to present the clinical experience of an 82-year-old man diagnosed with Streptococcus gallolyticus endocarditis and the incidental finding of adenomatous polyps of the colon(AU)

An in vitro evaluation of surface roughness, color stability and bacterial accumulation of lithium disilicate ceramic after prophylactic periodontal treatment / Avaliação in vitro da rugosidade superficial, estabilidade de cor e acúmulo bacteriano em cerâmica de dissilicato de lítio após tratamento de profilaxia periodontal

Objective: To evaluate the effect of scaling procedures using different ultrasonic tips on the surface roughness, color stability and bacterial accumulation of lithium disilicate ceramic. Material and Methods: Scaling procedure was carried out using ultrasonic scaler (Satalec, Acteon, North America) with stainless-steel tip (US), titanium tip (UT) and plastic tip (UP), on disc shaped lithium disilicate samples cemented into a cavity prepared onto the labial surface of freshly extracted bovine teeth (10 samples per group). The samples were stored in coffee solution in an incubator at 37°C for 12 days, which is equivalent to 1 year of coffee consumption. The surface roughness was measured before and after the scaling procedure using a profilometer and atomic force microscopy. The color parameters were measured before and after scaling and staining procedures using VITA Easyshade Advance 4.0 according to the CIE L*a*b* color order system. The samples were then incubated with Streptococcus mutans (S. mutans) suspension. After incubation, the plates with 30 to 300 typical colonies of S. mutans were counted in a colony counter and mean values of colony forming units were obtained (CFU/mL). Results:The titanium scaling tip showed a statistically significant higher mean values of change in surface roughness ΔRa and bacterial count than the plastic scaling tip. Color changes (ΔE) were not a statistically significant among the groups. The results showed a statistically significant positive (direct) correlation between surface roughness and color change (p = 0.012) and also between surface roughness and bacterial count (p = 0.00). Conclusion: Within the limitations of this study, titanium scaling instruments cause irreversible surface alterations of lithium disilcate ceramics which was in direct correlation to the color changes and bacterial accumulation; therefore, dentists should proceed with caution when scaling lithium disilicate surfaces. The findings of the current study may indicate the need for instruments or equipment that can remove plaque and calculus without causing surface damage (AU)

Introdução: Avaliar o efeito de procedimentos de raspagem com diferentes pontas de ultrassom na rugosidade superficial, estabilidade de cor e acúmulo bacteriano em cerâmica de dissilicato de lítio. Material e Métodos: O procedimento de raspagem foi realizado usando um aparelho de ultrassom (Satalec, Acteon, América do Norte) com ponta de aço inoxidável (US), ponta de titânio (UT) e ponta de plástico (UP), em amostras de dissilicato de lítio em forma de disco cimentadas em uma cavidade preparada na superfície vestibular de dentes bovinos recém-extraídos (10 amostras por grupo). As amostras foram armazenadas em solução de café em incubadora a 37 ° C por 12 dias, o que equivale a 1 ano de consumo de café. A rugosidade da superfície foi medida antes e após o procedimento de raspagem usando um perfilômetro e um microscópio de força atômica. Os parâmetros de cor foram medidos antes e depois dos procedimentos de raspagem e armazenagem no café usando VITA Easyshade Advance 4.0 de acordo com o sistema de ordem de cores CIE L*a*b*. As amostras foram incubadas com suspensão de Streptococcus mutans (S. mutans). Após a incubação, as placas com 30 a 300 colônias típicas de S. mutans foram contadas em contador de colônias e obtidos os valores médios das unidades formadoras de colônias (UFC / mL). Resultados: A ponta de titânio mostrou valores estatisticamente maiores de mudança na rugosidade da superfície ΔRa e contagem de bactérias do que a ponta de raspagem de plástico. A mudança de cor (ΔE) não foi estatisticamente significativa entre os grupos. Os resultados mostraram uma correlação positiva (direta) estatisticamente significativa entre rugosidade superficial e alteração de cor (p = 0,012) e também entre rugosidade superficial e contagem bacteriana (p = 0,00). Conclusão: Dentro das limitações deste estudo, os instrumentos de raspagem de titânio causam alterações irreversíveis na superfície das cerâmicas de dissilicato de lítio que estão em correlação direta com as mudanças de cor e o acúmulo de bactérias. Portanto, os dentistas devem proceder com cautela ao realizar raspagem em superfícies de dissilicato de lítio. Os resultados deste estudo podem indicar a necessidade de instrumentos ou equipamentos que possam remover a placa e cálculo sem causar danos à superfície. (AU)

Influence of EDTA and its Association with Benzalkonium Chloride on Enterococcus faecalis Adhesion to Dentin / Influencia del EDTA y su Asociación con Cloruro de Benzalconio en la Adhesión de Enterococcus faecalis a la Dentina

ABSTRACT: The aim of this in vitro study was to investigate the influence of ethylenediaminetetraacetic acid (EDTA) associated with the benzalkonium chloride (BAK) on the adhesion and formation of Enterococcus faecalis biofilms attached to coated dentin. Discs standard bovine dentin blocks were treated with the coating materials evaluated: Saline solution (control), 17 % EDTA, 17 % EDTA associated with 1 % BAK for 5 minutes and subsequently washed with saline solution. Afterwards, biofilms of E. faecalis (ATCC 29212) were grown on the surface of coated dentin blocks for time intervals of 1 hour and 7 days (n = 20) and were subsequently washed with phosphate-buffered saline (PBS). Bacterial viability and total biovolume were analyzed by confocal laser scanning microscopy (CLSM) using the Live/Dead technique. Nonparametric Kruskal-Wallis followed by Dunn tests were used to determine statistical differences (a = 5 %). The 17 % EDTA + 1 % BAK group showed significantly lower biovolume and bacterial viability values at the end of 1 hour (p < 0.05). After 7 days of contamination, the 17 % EDTA and 17 % EDTA + 1 % BAK groups showed similar results that differed statistically from those of the control group (p < 0.05). The saline solution group showed higher values. The use of BAK associated with EDTA on dentin blocks surfaces before exposure to contamination was able to interfere in the adhesion of E. faecalis to dentin. Also, dentin treatment by BAK associated with a chelating agent influences the secondary biofilm formation, which could have important effects on the long-term success of root canal treatment.

RESUMEN: El objetivo del estudio consistió en investigar in vitro, la influencia del ácido etilendiamino-tetraacético (EDTA) con cloruro de benzalconio (BAK) en la adhesión y formación de biopelículas de Enterococcus faecalis a la dentina. Discos de dentina bovina fueron tratadas con solución salina (control), 17 % de EDTA, 17% de EDTA asociado con 1 % de BAK durante 5 minutos y lavadas con solución salina. Las biopelículas de E. faecalis (ATCC 29212) se cultivaron sobre los discos de dentina durante intervalos de tiempo de 1 hora y 7 días (n = 20), lavados con solución salina tamponada con fosfato (PBS). La viabilidad bacteriana y el biovolumen total se analizaron mediante microscopía de barrido por láser (CLSM) utilizando la técnica Live / Dead. Se realizó prueba no paramétrica de Kruskal-Wallis, seguida por Dunn con una diferencia estadística (a = 5 %). El grupo de 17 % EDTA + 1 % BAK mostró valores significativamente menores de biovolumen y viabilidad bacteriana al final de 1 hora (p < 0,05). Después de 7 días de contaminación, los grupos de 17 % EDTA y 17 % EDTA + 1 % BAK mostraron resultados similares que diferían estadísticamente del grupo control (p < 0,05). La solución salina mostró valores más altos. La asociación de BAK con EDTA antes de la contaminación interfirió en la adhesión de E. faecalis. Además, el tratamiento de la dentina por BAK asociado con EDTA influye en la formación de biopelículas secundarias, lo que podría tener efectos importantes sobre el éxito a largo plazo del tratamiento del conducto radicular.

Influência da adesão bacteriana em resina composta Bulk fill submetida a diferentes protocolos de acabamento e polimento: estudo in vitro / Influence of bacterial adhesion on Bulk fill composite resin submitted to different finishing and polishing protocols: in vitro study

Objetivo: avaliar a adesão bacteriana do Streptococcus mutans na superfície de uma resina composta do tipo incremento único submetida a diferentes protocolos de polimento. Materiais e métodos: foram realizadas 60 amostras nas quais foram divididas aleatoriamente em 6 grupos (n=10) de diferentes tratamentos de superfície. Cinco amostras de cada grupo foram separadas e submetidas ao estudo de adesão bacteriana, das quais duas foram analisadas pela microscopia eletrônica de varredura. Foram contabilizadas as unidades formadoras de colônias UFC/ml de modo manual e realizada a média e desvio padrão de cada grupo. De acordo com os resultados analisados através do teste de One Way ANOVA e comparações múltiplas de Tukey observou-se uma diferença estatisticamente significativa entre os grupos. Resultados: os valores de UFC/ mL variaram de 0 para o grupo American Burrs a 8,64 para o grupo Dhpro. Os grupos Jota e Dhpro não diferiram estatisticamente entre si (p=0,71), porém diferiram dos demais grupos avaliados (p=0,45). Os grupos American Burrs e o controle negativo não diferiram estatisticamente entre si (p>0.999) e diferiram dos demais grupos testados (p=0,20). O grupo de controle positivo diferiu estatisticamente dos outros grupos (p=0,02) assim como o grupo KG (p=0,01). Conclusão: Diante dos resultados obtidos, pode-se concluir que, a superfície da resina Bulk Fill One submetida a diferentes protocolos de polimento e mesmo sem ter passado por nenhum tratamento de superfície é passível de adesão bacteriana seja por contagem manual ou microscopia eletrônica de varredura(AU)

Objective: To evaluate the bacterial adhesion of Streptococcus mutans on the surface of a single increment composite resin submitted to different polishing protocols. Materials and methods: 60 samples were randomly divided into 6 groups (n = 10) of different surface treatments. Five samples from each group were separated and submitted to the bacterial adhesion study, two of which were analyzed by scanning electron microscopy. The UFC/ml colony forming units were accounted for manually and the mean and standard deviation of each group were performed. According to the results analyzed by the One Way ANOVA test and Tukey's multiple comparisons, a statistically significant difference was observed between the groups. Results: The values ranged from 0 for the American Burrs group to 8.64 for the Dhpro group. The Jota and Dhpro groups did not differ statistically (p = 0.71), but differed from the other groups evaluated (p = 0.45). The American Burrs and negative control groups did not differ statistically (p> 0.999) and differed from the other groups tested (p = 0.20). The positive control group differed statistically from the other groups (p = 0.02) as did the KG group (p = 0.01). Conclusion: It can be concluded that the surface of the Bulk Fill One resin submitted to different polishing protocols and even without any surface treatment is susceptible to bacterial adhesion either by manual counting or scanning electron microscopy(AU)

Antimicrobial Orthodontic Wires Coated with Silver Nanoparticles

Abstract Conventional orthodontic treatment with the use of stainless steel may be detrimental to oral health by promoting demineralizing lesions appearance and increasing adhesion and formation of bacterial biofilm, inducing the development of cavities. An alternative that has been researched to reduce the side effects of orthodontic treatment is the coating of materials with antimicrobial nanoparticles. Nanometric- sized particles increase their surface area and contact with the microbial membrane, consequently intensifying their bacteriostatic and bactericidal effect. In this work, hydrothermal synthesis, a "green" process was used to attach silver nanoparticles (AgNPs) to the surface of two different brands of orthodontic wires. The coated materials were analyzed for their physicochemical properties by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), which showed the distribution of AgNPs along the wires without modifying their properties. In the microbiological test, one of the brands showed a statistically significant difference in microbial adhesion and biofilm formation by Staphylococcus aureus and Streptococcus mutans. Results lead to the conclusion that antimicrobial orthodontic wires coated with silver nanoparticles through hydrothermal synthesis is a promising material for the improvement of orthodontic treatment.

"Amar" el índice de O'Leary / The O'Leary index, a.k.a. the "Love" index

La detección y cuantificación de placa dental bacteriana se considera básica en la práctica de la estomatología. El índice O'Leary constituye una herramienta sencilla que mide la cantidad de placa dental bacteriana en los dientes, y resulta uno de los más efectivos en la evaluación de la higiene bucal. La connotación que tiene la higiene bucal en varias esferas de la vida quizás llevó a que este índice fuera bautizado en Cuba como índice de Love (Amor); por lo que nos proponemos esclarecer la conveniencia del empleo de la denominación internacional de este(AU)

Detection and quantification of bacterial dental plaque is considered to be crucial in dental practice. The O'Leary index is a simple tool to measure the amount of bacterial dental plaque on teeth and one of the most effective means to evaluate oral hygiene. The connotation of oral hygiene in several spheres of life is probably the reason why this index is also known in Cuba as the Love Index. We intend to shed light on the advisability of using the international term(AU)

Bacterial colonization of composite resins used with direct technique: a brief review

In restorative dentistry, the use of composite resins with direct technique for the replacement of missing tooth structure is very common. One drawback is that surface roughness allows the adherence of microorganisms and the formation of dental plaque, being the polishing technique a key stage in the restoration process. The aim of this paper is to review the process of bacterial colonization of composite resins used with direct technique. According to in vitro studies, bac-terial adhesion on microhybrid composite resins is 3.91 ± 0.52 UFC and on nanohybrid is 3.34 ± 0.74 UFC. Resins with particle size of 2.5 micrometers contained a greater volume of biofilms and enabled adhesion of S. mutans; in turn, resins with particle size of 0.1 to 0.4 micrometers showed lower bacterial adherence. As summary, the degree of bacterial colonization depends on hygiene, polishing technique and composition of restorative material: the bigger the particle size, the greater the adhesion of bacterial plaque.

Adhesión Bacteriana en Hilo de Sutura de Seda Negra y Nylon Post Extracción Dental Simple: Ensayo Clínico Controlado / Bacterial Adhesion in Black Silk Suture Thread and Nylon Post Simple Dental Extraction: Controlled Clinical Trial

RESUMEN: El objetivo de este estudio fue comparar los hilos de sutura de seda negra y la sutura nylon con respecto a la adhesión bacteriana post extracción dental simple de piezas posteriores. El presente trabajo se desarrolló en la Clínica Odontológica y el Laboratorio de Microbiología de la Unidad de Ciencias Biomédicas y Biotecnología de la Universidad Privada Antenor Orrego (Trujillo, Perú), entre agosto y setiembre de 2014. Se trabajó con 19 unidades de muestreo para hilo de seda negra y 19 para nylon. El procedimiento de exodoncia para todos los pacientes fue estandarizado. Luego de la extracción, se procedió a suturar la herida quirúrgica, colocando dos puntos circunferenciales, uno con cada tipo de hilo. A los 7 días, los hilos fueron retirados y sometidos a análisis microbiológico. La adhesión bacteriana de los hilos de sutura seda negra y nylon fue comparada empleando el test de Wilcoxon. Además la adhesión bacteriana de cada hilo fue comparada con la adhesión en hilos estériles (control) empleando el test de Mann-Whitney para una p<0,005. Al comparar la adhesión bacteriana de ambos hilos, se encontró diferencia entre ellos (p=0,027), correspondiendo mayor adhesión al hilo de nylon. La adhesión bacteriana fue mayor en el hilo de sutura de nylon comparado con el hilo de sutura de seda negra.

ABSTRACT: The objective of the study was to compare black silk suture threads and nylon suture with respect to bacterial adhesion after simple dental extraction of posterior pieces. The present study was developed in the Clínica Estomatológica and the Laboratorio de Microbiología of the Unidad de Ciencias Biomédicas y Biotecnología de la Universidad Privada Antenor Orrego (Trujillo, Peru), between August and September 2014. We worked with 19 units sampling for black silk thread and 19 for nylon. The procedure of exodontia for all patients was standardized. After the extraction, the surgical wound was sutured, placing two circumferential points, one with each type of thread. After 7 days, the threads were removed and subjected to microbiological analysis. The bacterial adhesion of the black silk and nylon suture strands was compared using the Wilcoxon test. In addition, the bacterial adhesion of each strand was compared with the adhesion in sterile strands (control) using the Mann-Whitney test for p <0.005. When comparing the bacterial adhesion of both threads, a difference was found between them (p = 0.027), corresponding greater adhesion to the nylon thread. Bacterial adhesion was higher in nylon suture compared to black silk suture.

Retraction: Bacterial adhesion and colonization differences between zirconia and titanium implant abutments: an in vivo human study

This article has been retracted at the request of the Editor-in-Chief, because the authors plagiarized a previously published paper that had appeared in: Int J Oral Maxillofac Implants, 26 (2011) 101–107. This article presented the same table and figures as the original study, and changed 2 of the tables to figures. This article reflects severe abuse of the scientific publishing system, and has therefore been retracted.

Virulence genes of Streptococcus mutans and dental caries

Streptococcus mutans is one of the important bacteria that forms dental biofilm and cause dental caries. Virulence genes in S. mutans can be classified into the genes involved in bacterial adhesion, extracellular polysaccharide formation, biofilm formation, sugar uptake and metabolism, acid tolerance, and regulation. The genes involved in bacterial adhesion are gbps (gbpA, gbpB, and gbpC) and spaP. The gbp genes encode glucan-binding protein (GBP) A, GBP B, and GBP C. The spaP gene encodes cell surface antigen, SpaP. The genes involved in extracellular polysaccharide formation are gtfs (gtfB, gtfC, and gtfD) and ftf, which encode glycosyltransferase (GTF) B, GTF C, and GTF D and fructosyltransferase, respectively. The genes involved in biofilm formation are smu630, relA, and comDE. The smu630 gene is important for biofilm formation. The relA and comDE genes contribute to quorum-sensing and biofilm formation. The genes involved in sugar uptake and metabolism are eno, ldh, and relA. The eno gene encodes bacterial enolase, which catalyzes the formation of phosphoenolpyruvate. The ldh gene encodes lactic acid dehydrogenase. The relA gene contributes to the regulation of the glucose phosphotransferase system. The genes related to acid tolerance are atpD, aguD, brpA, and relA. The atpD gene encodes F1F0-ATPase, a proton pump that discharges H⁺ from within the bacterium to the outside. The aguD gene encodes agmatine deiminase system and produces alkali to overcome acid stress. The genes involved in regulation are vicR, brpA, and relA.

Effects of different finishing/polishing protocols and systems for monolithic zirconia on surface topography, phase transformation, and biofilm formation

PURPOSE: The purpose of this study was to evaluate the effects of various protocols and systems for finishing and polishing monolithic zirconia on surface topography, phase transformation, and bacterial adhesion. MATERIALS AND METHODS: Three hundred monolithic zirconia specimens were fabricated and then treated with three finishing and polishing systems (Jota [JO], Meisinger [ME], and Edenta [ED]) using four surface treatment protocols: coarse finishing alone (C); coarse finishing and medium polishing (CM); coarse finishing and fine polishing (CF); and coarse finishing, medium polishing, and fine polishing (CMF). Surface roughness, crystal phase transformation, and bacterial adhesion were evaluated using atomic force microscopy, X-ray diffraction, and streptococcal biofilm formation assay, respectively. One-way and two-way analysis of variance with Tukey post hoc tests were used to analyze the results (α=.05). RESULTS: In this study, the surface treatment protocols and systems had significant effects on the resulting roughness. The CMF protocol produced the lowest roughness values, followed by CM and CF. Use of the JO system produced the lowest roughness values and the smallest biofilm mass, while the ME system produced the smallest partial transformation ratio. The ED group exhibited the highest roughness values, biofilm mass, and partial transformation ratio. CONCLUSION: Stepwise surface treatment of monolithic zirconia, combined with careful polishing system selection, is essential to obtaining optimal microstructural and biological surface results.

Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation

PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05). RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P < .001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

Surface characteristics of pure titanium loaded graphene oxide: effect on bacteria adhesion and osteoblast structure / 华西口腔医学杂志

OBJECTIVE@#To evaluate the process characterization of graphene oxide loaded on pure titanium surface and effect on the biological properties of Staphylococcus aureus and osteoblasts.@*METHODS@#Graphene oxide at four concentrations (20, 50, 80, and 100 µg·mL⁻¹) was loaded on the pure titanium surface via electroplating, and the morphology, properties, and hydrophilic properties were measured with a field emission scanning electron microscope, micro Raman spectrometer, and contact angle tester, respectively. In addition, Staphylococcus aureus and osteoblasts were used as models and cultured with pure titanium-graphene oxide. Then, field-emission scanning electron microscopy and laser confocal microscopy were utilized to observe the changes in the amount of bacteria and osteoblast morphology and structure, respectively.@*RESULTS@#Graphene oxide at the four concentrations was successfully loaded on pure titanium surface via electroplating. It improved the hydrophilic properties of pure titanium surface, which benefitted the adhesion and growth of Staphylococcus aureus and changed the morphology and structure of the osteoblasts.@*CONCLUSIONS@#The pure titanium-graphene oxide composite has no antibacterial properties and has good biocompatibility.

Polymorphism analysis of virulence-related genes among Candida tropicalis isolates / 中华医学杂志(英文版)

BACKGROUND@#Adhesion, biofilm formation, yeast-hyphal transition, secretion of enzymes, and hemolytic activity are all considered important factors in Candida tropicalis infection. However, DNA sequence data for this pathogen are limited. In this study, the polymorphism and heterogeneity of genes agglutinin-like sequences (ALS)2, Lipase (LIP)1, LIP4, and secretory aspartyl proteinase tropicalis (SAPT)1-4 as well as the relationship between phenotype and genotype were analyzed.@*METHODS@#This study started in August 2013, and ended in July 2017. The complete length of ALS2, LIP1, LIP4, and SAPT1-4 of 68 clinical C. tropicalis isolates was sequenced. Single nucleotide polymorphisms (SNPs) as well as insertions and deletions (indels) were identified within these genes. In addition, phenotypic characteristics of the virulent factors, including adhesion and the secretion of aspartyl proteinases and phospholipases, were determined.@*RESULTS@#There were 73, 24, 17, 16, 13, and 180 SNPs in the genes LIP1, LIP4, SAPT1, SAPT2, SAPT3, and SAPT4, respectively. Furthermore, 209 SNPs were identified in total for the gene ALS2. Interestingly, large fragment deletions and insertions were also found in ALS2. Isolate FXCT 01 obtained from blood had deletions on all 4 sites and showed the lowest adhesion ability on the polymethylpentene surface. In addition, isolates with deletions in the regions 1697 to 1925 and 2073 to 2272 bp displayed relatively low abilities for adhesion and biofilm formation, and this phenotype correlated with the deletions found in ALS2. LIP1, SAPT4, and ALS2 displayed great heterogeneity among the isolates. Large deletions found in gene ALS2 appeared to be associated with the low ability of adhesion and biofilm formation of C. tropicalis.@*CONCLUSION@#This study might be useful for deeper explorations of gene function and studying the virulent mechanisms of C. tropicalis.

Application of nanodrug carriers in the prevention and treatment of infection around orthopedic prosthesis / 生物医学工程学杂志

Despite the continuous improvement in perioperative use of antibiotics and aseptic techniques, the incidence of infection continues to rise as the need for surgery increasing and brings great challenges to orthopedic surgery. The rough or porous structure of the prosthesis provides an excellent place for bacterial adhesion, proliferation and biofilm formation, which is the main cause of infection. Traditional antibiotic therapy and surgical debridement are difficult to determine whether the infected focus have been removed completely and whether the infection will recur. In recent years, nanotechnology has shown obvious advantages in biomaterials and drug delivery. Nano drug carriers can effectively achieve local antimicrobial therapy, prevent surgical infection by local sustained drug release or intelligent controlled drug release under specific stimuli, and reduce the toxic side effects of drugs. The unique advantages of nanotechnology provide new ideas and options for the prevention and treatment of periprosthetic infection. At present, the application of nano-technology in the prevention and treatment of infection can be divided into the addition of nano-drug-loaded materials to prosthesis materials, the construction of drug-loaded nano-coatings on the surface of prosthesis, the perfusable nano-antimicrobial drug carriers, and the stimulation-responsive drug controlled release system. This article reviews the methods of infection prevention and treatment in orthopaedic surgery, especially the research status of nanotechnology in the prevention and treatment of periprosthetic infection.

Microbial etiology of community acquired pneumonia among infants and children admitted to zagazig university pediatric hospital

Background: While recognizing the etiology of community-acquired pneumonia is necessary for formulating local antimicrobial guidelines, limited data is published about this etiology in Egyptian pediatric patients. The aim of this study is to elucidate the common bacterial pathogens causing CAP among immunocomptent infants and preschool children admitted to Zagazig university Pediatric hospital. Methods: 48 infant and preschool children admitted to pediatric hospital of Zagazig university and presented with signs of pneumonia according to WHO. Etiological agents were identified using conventional bacteriological identification methods and Ig M antibodies detection against common a typical bacteria and respiratory viruses. Results: Staph. Aureus 35.4% is the most common pathogen detected in sputum regardless the age group .In blood culture results negative results in most cases of pneumonia 62.5%. Staph. Aureus is the most common pathogen detected in blood culture in positive cases regardless the age group 18.7% , E Coli 6.25%, Klebsiella 2.08.In Serology results significant difference according to age in viral pneumonia occurrence and non significant difference in bacterial pneumonia based on serological findings with higher diagnosis of Legionella pneumophila 33.33% as a causative organism. Conclusion: This study provides preliminary data regarding the spectrum and frequency of microorganisms causing CAP in infants and preschool children