Irrigación Activada por Láser en Endodoncia

RESUMEN: El objetivo de la endodoncia es prevenir o curar la periodontitis apical. Por lo tanto, los microorganismos que han colonizado el sistema de canales radiculares deben ser eliminados para promover la regeneración y cicatrización. Desafortunadamente, la existencia de canales accesorios, anastomosis, istmos, así como ramificaciones apicales, genera una compleja red tridimensional en el interior de la raíz, lo que dificulta la eliminación total de bacterias y detritus. La te rapia endodóntica convencional utilizada actualmente presenta una serie de limitaciones.Se ha demostrado que los instrumentos endodónticos dejan un 35 % o más de superficie dentinaria sin tratar. Por otro lado, la imposibilidad de generar un flujo turbulento en el interior de los canales, impide que el irrigante llegue a zonas de difícil acceso. Esto facilita la persistenc ia de biopelículas bacterianas y la supervivencia de un número importante de bacterias viables. La irrigación activada por láser (LAI) ha sido propuesta como una tecnología co-adyuvante a la terapia quimio-mecánica para optimizarla limpieza y desinfección. Los láseresde Er,Cr:YSGG (2780nm) y Er:YAG (2940nm) son los más utilizados. Estas dos longitudes de onda son capaces de ser absorbidas ampliamente por diferentes soluciones irrigantes, teniendo en cuenta un uso seguro y respetando los parámetros clínicos aceptados. La absorción de la energía del láser por parte de los irrigantes, genera burbujas de vapor en el interior del fluido, que liberan fuerzas de cizalla al implosionar. Este fenómeno, denominado cavitación, genera mayor limpieza y desinfección del interior del sistema de canales radiculares, incluso en zonas de difícil acceso. Diversos estudios microbiológicos y microscópicos, han demostrado la efectividad antibacteriana de LAI. Recientemente, se ha publicado que LAI tendría la capacidad de incrementarla capacidad antibacteriana del hipoclorito de sodio a baja concentración (un buen desinfectante pero extraordinariamente tóxico), lo que permitiría trabajar con concentraciones menores y por lo tanto más seguras para el paciente.

ABSTRACT: The goal of endodontics is to prevent or cure apical periodontitis. Therefore, microorganisms that have colonized the root canal system must be eliminated to promote regeneration and healing. Unfortunately, the existence of accessory canals, anastomoses, isthmus, as well as apical ramifications, form a complex three-dimensional network inside the root, which makes difficult the total elimination of bacteria and detritus. Conventional endodontic therapy has several limitations. Endodontic instruments have been shown to leave 35 % or more of the dentin surface untreated. On the other hand, the inability of generating a turbulent flow, prevents the irrigant from reaching areas that are difficult to access. This facilitates the persistence of bacterial biofilms and the survival of a significant number of viable bacteria. Laser-activated Irrigation (LAI) has been proposed as a co-adjuvant to chemo-mechanical therapy to improve cleaning and disinfection. Er, Cr: YSGG (2780nm) and Er: YAG (2940nm) lasers are the most widely used. These two wavelengths are capable of being widely absorbed by different irrigating solutions, taking into account safe use and respecting accepted clinical parameters.The deep absorption of laser energy generates steam bubbles inside the fluid, which release shear forces when imploding. This phenomenon, called cavitation, is responsible for greater cleaning and disinfection within the root canal system, even in areas difficult to access. Several studies have demonstrated the antibacterial effectiveness of LAI through microbiological methods and microscopic techniques. Recently, it has been reported that LAI would have the ability to increase the antibacterial capacity of low concentration of sodium hypochlorite (a good disinfectant but extremely toxic), which would allow working with concentrations that are safer for the patient.

Using prodigiosin against some gram-positive and gram-negative bacteria and Trypanosoma cruzi

This work aimed to explore the action of natural prodigiosin on both bacterial organisms and Trypanosoma cruzi cells. Methods: Natural prodigiosin pigment was extracted and purified from cultures of Serratia marcescens. Two media, peanut broth and peptone glycerol broth, both recommended in the literature for prodigiosin production, were compared. The prodigiosin obtained was employed to explore its antimicrobial properties against both bacteria and Trypanosoma cruzi cells. Results: Peanut broth yielded four times more prodigiosin. The prodigiosin showed remarkable activity (minimal inhibitory concentrations in the range of 2-8 µM for bacteria and half maximal inhibitory concentration of 0.6 µM for Trypanosoma cruzi). In fact, the prodigiosin concentration required to inhibit parasite growth was as low as 0.25 mg/l versus 4.9 mg/l of benznidazole required. Furthermore, atomic force microscopy revealed marked morphological alterations in treated epimastigote forms, although no pore-formation activity was detected in protein-free environments. Conclusions: This work demonstrates the potential usefulness of prodigiosin against some gram-positive and gram-negative bacteria and Trypanosoma cruzi although further studies must be done in order to assess its value as a candidate molecule.(AU)

Virus en Endodoncia / Viruses in Endodontics

La infección endodóntica es la infección que afecta al sistema de conductos radiculares y, sin duda, es el principal agente etiológico de las periodontitis apicales. Además, de las bacterias patógenas endodónticas, se ha buscado en los últimos años asociar la presencia de virus en distintos tipos de patología endodóntica. Los virus que más se han buscado y asociado son los pertenecientes a la familia herpesvirus, los cuales se han encontrado presentes en patologías periapicales principalmente. Se ha buscado además, relacionar su presencia a patologías que cursan con mayor sintomatología, o que presentan a la imagen radiográfica destrucciones óseas periapicales mayores. El rol de los virus en las lesiones apicales de origen endodóntico está aún poco claro, se habla de efectos acumulativos a los de las bacterias, además de posibles inmunosupresiones locales que favorecerían el crecimiento y el efecto de estas últimas.

Endodontic infection is an infection of the root canal system and undoubtedly is the main etiological agent of apical periodontitis. In recent years, research has aimed to associate the presence of virus and endodontic bacterial pathogens in the different types of endodontic disease. The most common viruses that have been researched and associated are members of the herpesvirus family, which are mainly present in periapical pathologies. Furthermore, research has been carried out relating their presence to pathologies with important symptoms, or those where radiographic imaging shows extensive apical bone reabsorption. The role of viruses in apical lesions of endodontic origin are still unclear, it hypothesizes the cumulative effect with bacteria, in addition to possible local immunosuppression that favors the growth and the effect of bacteria.

Determinants of quinolone resistance in Escherichia coli causing community-acquired urinary tract infection in Bejaia, Algeria

OBJECTIVE@#To investigate the mechanisms of quinolone resistance and the association with other resistance markers among Esherichia coli (E. coli) strains isolated from outpatient with urinary tract infection in north of Algeria.@*METHODS@#A total of 30 nalidixic acid-resistant E. coli isolates from outpatient with urinary tract infections from January 2010 to April 2011 in north of Algeria (Bejaia) were studied. Antimicrobial susceptibility was determined by disc diffusion assay, minimal inhibitory concentrations (MIC) of quinolone were determined by microdilution. Mutations in the Quinolone Resistance-Determining Region (QRDR) of gyrA and parC genes and screening for qnr (A, B and S) and bla genes were done by PCR and DNA sequencing.@*RESULTS@#Most of the E. coli isolates (56.66%) were shown to carry mutations in gyrA and parC (gyrA: Ser83Leu + Asp87Asn and parC:Ser80Ile). While, 16.66% had only an alteration in gyrA: Ser83Leu. One isolate produced qnrB-like and two qnrS-like. Four isolates were CTX-M-15 producers associated with TEM-1 producing in one case. Co-expression of blaCTX-M-15 and qnrB was determined in one E. coli isolate.@*CONCLUSIONS@#Our findings suggested the community emergence of gyrA and parC alterations and Qnr determinants that contributed to the development and spread of fluoroquinolone resistance in Algerian E. coli isolates.