Mi agradecimiento a Sherry Kuchma, Pete Newell y Robert Shanks para ofrecer las imágenes en la Figura 1. Este trabajo fue apoyado por el NIH subvención R01AI083256 de la GAO

1. El crecimiento de un biofilm <ol><li> Cultivar una cultura de la de tipo salvaje aeruginosa Pseudomonas o cepa mutante durante la noche en un medio rico (LB es decir) </li><li> Diluir el 1:100 noche sobre la cultura en un nuevo medio para los ensayos de biofilm. Un biofilm estándar medio de cultivo de P. aeruginosa es M63 medio mínimo suplementado con sulfato de magnesio, la glucosa y los ácidos casamino (véase el cuadro). Como un biofilm, la promoción de alternativas de medio que estimula el menor crecimiento del plancton y biofilms más robusta, la glucosa y los ácidos casamino puede ser sustituida por arginina como el carbón y la única fuente de energía. </li><li> Añadir 100 ml de la dilución por pocillo en una placa de 96 pocillos. Para los ensayos cuantitativos, por lo general utilizan pozos 4-8 replicar para cada tratamiento. </li><li> Incubar la placa de microtitulación de 4.24 horas a 37 ° C. </li></ol> 2. Tinción de la biopelícula <ol><li> Después de la incubación, volcado a las células girando el plato una y sacudir el líquido. </li><li> Suavemente sumergir la placa en una pequeña tina de agua (es decir, utilizar los fondos de cajas de puntas para pipeta P1000 pipetmen como la bañera). Sacuda el agua. Repita este proceso por segunda vez. Este paso ayuda a eliminar las células sueltas y componentes de los medios de comunicación que se puede teñir en el siguiente paso, y reduce significativamente la tinción de fondo. </li><li> Añadir 125 l de una solución al 0,1% de cristal violeta en el agua a cada pocillo de la placa de microtitulación. Use guantes y una bata de laboratorio al hacer la solución. Tenga cuidado al peso de la CV como el polvo es higroscópico y fácilmente las manchas de la ropa, piel, etc </li><li> Incubar la placa de microtitulación a temperatura ambiente durante 10-15 min. </li><li> Enjuague la placa de 3-4 veces con agua por inmersión en una tina de agua como se indicó anteriormente, sacudir y secar con fuerza en una pila de toallas de papel para eliminar la placa de todas las células y el exceso de tinte. </li><li> Gire la placa de microtitulación boca abajo y en seco por unas horas o toda la noche. </li><li> Para los ensayos cualitativos, los pozos pueden ser fotografiados cuando se seca. </li></ol> 3. La cuantificación de la biopelícula <ol><li> Añadir 125 l de 30% de ácido acético en agua a cada pocillo de la placa de microtitulación para solubilizar el CV. </li><li> Incubar la placa de microtitulación a temperatura ambiente durante 10-15 min. </li><li> Transferencia de 125 l de la CV solubiliza a un nuevo plato de microtitulación de fondo plano. </li><li> Cuantificar la absorbancia en un lector de placas a 550 nm utilizando 30% de ácido acético en agua como blanco. </li></ol> 4. Los resultados representativos: <img src="/files/ftp_upload/2437/2437fig1.jpg" alt="Figura 1" /> Figura 1. Muestra un resultado representativo para los ensayos de la formación del biofilm realizado por Pseudomonas aeruginosa, Pseudomonas fluorescens y Staphylococcus aureus. (A) A la vista lateral del pozo con un biofilm de P. aeruginosa (8 horas, 37 ° C). (B) A la vista lateral del pozo con un biofilm de P. fluorescens (6 horas, 30 ° C). (C) Una visión de arriba hacia abajo de la formación de biopelículas de S. aureus en una placa de microtitulación de fondo plano (dos pozos, 24 horas, 37 ° C). P. aeruginosa y P. fluorescens son organismos móviles y forman un biofilm en la interfase aire-líquido. S. aureus es no móviles y forma una biopelícula sobre el fondo del pozo.

<ol>
	<li>O'Toole, G. A., Kolter, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Initiation+of+biofilm+formation+in+Pseudomonas+fluorescens+WCS365+proceeds+via+multiple,+convergent+signalling+pathways:+a+genetic+analysis.">Initiation of biofilm formation in Pseudomonas fluorescens WCS365 proceeds via multiple, convergent signalling pathways: a genetic analysis.</a> Mol. Microbiol. 28, 449-461 (1998).</li><li>O'Toole, G. A., Doyle, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Methods in Enzymology. , 91-109 (1999).</li><li>Mah, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+genetic+basis+for+Pseudomonas+aeruginosa+biofilm+antibiotic+resistance.">A genetic basis for Pseudomonas aeruginosa biofilm antibiotic resistance.</a> Nature. 426, 306-310 (2003).</li><li>Kuchma, S. L., Connolly, J. P., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+three-component+regulatory+system+regulates+biofilm+maturation+and+type+III+secretion+in+Pseudomonas+aeruginosa.">A three-component regulatory system regulates biofilm maturation and type III secretion in Pseudomonas aeruginosa.</a> J Bacteriol. 187, 1441-1454 (2005).</li><li>Caiazza, N. C., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SadB+is+required+for+the+transition+from+reversible+to+irreversible+attachment+during+biofilm+formation+by+Pseudomonas+aeruginosa+PA14.">SadB is required for the transition from reversible to irreversible attachment during biofilm formation by Pseudomonas aeruginosa PA14.</a> J Bacteriol. 186, 4476-4485 (2004).</li><li>Shanks, R. M., Sargent, J. L., Martinez, R. M., Graber, M. L., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catheter+lock+solutions+influence+staphylococcal+biofilm+formation+on+abiotic+surfaces.">Catheter lock solutions influence staphylococcal biofilm formation on abiotic surfaces.</a> Nephrol Dial Transplant. 21, 2247-2255 (2006).</li><li>Caiazza, N. C., Merritt, J. H., Brothers, K. M., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inverse+regulation+of+biofilm+formation+and+swarming+motility+by+Pseudomonas+aeruginosa+PA14.">Inverse regulation of biofilm formation and swarming motility by Pseudomonas aeruginosa PA14.</a> J. Bacteriol. 189, 3603-3612 (2007).</li><li>Hinsa, S. M., Espinosa-Urgel, M., Ramos, J. L., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transition+from+reversible+to+irreversible+attachment+during+biofilm+formation+by+Pseudomonas+fluorescens+WCS365+requires+an+ABC+transporter+and+a+large+secreted+protein.">Transition from reversible to irreversible attachment during biofilm formation by Pseudomonas fluorescens WCS365 requires an ABC transporter and a large secreted protein.</a> Mol Microbiol. 49, 905-918 (2003).</li><li>Mack, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+transposon+mutants+of+biofilm-producing+Staphylococcus+epidermidis+impaired+in+the+accumulative+phase+of+biofilm+production:+genetic+identification+of+a+hexosamine-containing+polysaccharide+intracellular+adhesin.">Characterization of transposon mutants of biofilm-producing Staphylococcus epidermidis impaired in the accumulative phase of biofilm production: genetic identification of a hexosamine-containing polysaccharide intracellular adhesin.</a> Infect. Immun. 62, 3244-3253 (1994).</li><li>Vidal, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+an+Escherichia+coli+K-12+mutant+strain+able+to+form+biofilms+on+inert+surfaces:+involvement+of+a+new+ompR+allele+that+increases+curli+expression.">Isolation of an Escherichia coli K-12 mutant strain able to form biofilms on inert surfaces: involvement of a new ompR allele that increases curli expression.</a> J. Bacteriol. 180, 2442-2449 (1998).</li><li>Junker, L. M., Clardy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+screens+for+small-molecule+inhibitors+of+Pseudomonas+aeruginosa+biofilm+development.">High-throughput screens for small-molecule inhibitors of Pseudomonas aeruginosa biofilm development.</a> Antimicrob Agents Chemother. 51, 3582-3590 (2007).</li></ol>

Este método puede ser modificado para su uso con una amplia variedad de especies microbianas. Microbios móviles suelen adherirse a las paredes y / o en el fondo de los pozos, mientras que los no-móviles microbios normalmente se adhieren al fondo de los pozos. Las condiciones óptimas para la formación de biofilm (es decir, el medio de cultivo, temperatura, tiempo de incubación) debe ser determinada empíricamente para cada microbio. Recomiendo la realización de múltiples repeticiones para cada cepa o condición (...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>1 X M63</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>Prepare as a 5X M63 stock by dissolving 15g KH2PO4, 35g K2HPO4 and 10g (NH4)2SO4 in 1 L of water. This stock does not need to be autoclaved and can be stored at room temperature. Dilute 5X stock 1:5, autoclave, cool, then add the desired components.</td>
</tr>
<tr>
<td>KH2PO4</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>P285-500</td>
<td>&nbsp;</td>
<tr>
<td>K2HPO4</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>P288-500</td>
<td>&nbsp;</td>
<tr>
<td>(NH4)2SO4</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A5132</td>
<td>&nbsp;</td>
<tr>
<td>Magnesium sulfate</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>M63-500</td>
<td>Add to 1 mM final concentration. Prepare as a 1 M stock in water and autoclave.</td>
</tr>
<tr>
<td>Glucose</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>D16-3</td>
<td>Add to 0.2% final concentration. Prepare as a 20% stock in water and autoclave.</td>
</tr>
<tr>
<td>Casamino acids</td>
<td>&nbsp;</td>
<td>Beckton-Dickinson</td>
<td>223050</td>
<td>Add to 0.5% final concentration. Prepare as a 20% stock in water and autoclave.</td>
</tr>
<tr>
<td>Arginine</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A5131</td>
<td>Add to 0.4% final concentration. Prepare as a 20% stock in water and filter sterilize. This alternative carbon/energy source can replace glucose and casamino acids</td>
</tr>
<tr>
<td>Microtiter plates</td>
<td>&nbsp;</td>
<td>Beckton-Dickinson</td>
<td>353911</td>
<td>Falcon 3911, Microtest III, Flexible assay plates, 96 well, U-bottom, non-sterile, non-tissue-culture treated.</td>
</tr>
<tr>
<td>Microtiter plate lids</td>
<td>&nbsp;</td>
<td>Beckton-Dickinson</td>
<td>353913</td>
<td>The lids can be reused by cleaning with 95% ethanol in water.</td>
</tr>
<tr>
<td>Crystal violet</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>229641000</td>
<td>Prepare as a 0.1% solution in water.</td>
</tr>		</tbody>
		</table>
		</div>

microtiter dish biofilm formation assay

Los biofilms son comunidades de microorganismos adheridos a las superficies, que se puede encontrar en los centros médicos, industriales y naturales. De hecho, la vida en una biopelícula probablemente representa el modo predominante de crecimiento de los microbios en la mayoría de entornos. Biofilms maduros tienen algunas características distintas. Microbios biofilm son típicamente rodeados por una matriz extracelular que proporciona la estructura y la protección a la comunidad. Los microbios que crecen en un biofilm también tienen una arquitectura característica generalmente compuesto por macrocolonies (que contiene miles de células), rodeada de canales llenos de líquido. Biofilm crecido microbios también son conocidos por su resistencia a una amplia gama de agentes antimicrobianos, como los antibióticos clínicamente relevantes. El ensayo de placa de microtitulación es una herramienta importante para el estudio de las primeras etapas de formación del biofilm, y se ha aplicado principalmente para el estudio de las biopelículas bacterianas, aunque este ensayo también se ha utilizado para estudiar la formación de biopelículas fúngicas. Debido a que esta prueba se utiliza estática, el crecimiento de lotes condiciones, que no permite la formación de las biopelículas maduras típicamente asociados con los sistemas de celda de flujo. Sin embargo, el ensayo ha sido eficaz en la identificación de muchos factores necesarios para el inicio de la formación del biofilm (es decir, los flagelos, pili, adhesinas, enzimas que participan en cíclica-di-GMP vinculante y el metabolismo) y así como los genes implicados en la producción de polisacáridos extracelulares. Además, los trabajos publicados indican que los biofilms cultivadas en placas de microtitulación se desarrollan algunas de las propiedades de los biofilms maduros, con una tolerancia de antibióticos y la resistencia a los efectores del sistema inmune. Este ensayo de microtitulación plato sencillo permite la formación de un biofilm en la pared y / o fondo de un plato de microtitulación. La naturaleza de alto rendimiento de la prueba lo hace útil para las pantallas de genética, así como la formación de biofilm por pruebas de múltiples cepas en condiciones de crecimiento diferentes. Las variantes de este ensayo se han utilizado para evaluar la formación de biofilm principios para una amplia variedad de microbios, incluyendo pero no limitado a, Pseudomonas, Vibrio cholerae, Escherichia coli, staphylocci, enterococos, micobacterias y hongos. En el protocolo descrito aquí, nos centraremos en el uso de este ensayo para estudiar la formación de biofilm por el organismo Pseudomonas aeruginosa modelo. En este ensayo, la extensión de la formación de biopelículas se mide utilizando el colorante cristal violeta (CV). Sin embargo, una serie de manchas de colorimetría y metabólicas se han reportado para la cuantificación de la formación de biopelículas utilizando el ensayo de placa de microtitulación. La facilidad, bajo coste y la flexibilidad del ensayo de placa de microtitulación se ha convertido en una herramienta fundamental para el estudio de las biopelículas.

Watch this Scientific Journal Video about Microtiter Dish Biofilm Formation Assay at JoVE.com

Microtiter Dish Biofilm Formation Assay

El ensayo describe un método rápido para medir la formación de biopelículas a principios de bacterias y hongos. Este método utiliza una placa de microtitulación como sustrato para la formación de biopelículas microbianas, y el biofilm se visualiza utilizando la cepa de cristal violeta. El ensayo ofrece ya sea un ensayo cualitativo o cuantitativo de la formación de biofilm temprano.

Plato de microtitulación de formación de biopelículas de ensayo

Biofilms are communities of microbes attached to surfaces, which can be found in medical, industrial and natural settings.  In fact, life in a biofilm ...

Research

JoVE Journal

Immunology and Infection

107.8K vistas.  Dartmouth Medical School. El ensayo describe un método rápido para medir la formación de biopelículas a principios de bacterias y hongos. Este método utiliza una placa de microtitulación como sustrato para la formación de biopelículas microbianas, y el biofilm se visualiza utilizando la cepa de cristal violeta. El ensayo ofrece ya sea un ensayo cualitativo o cuantitativo de la formación de biofilm temprano.

Video: Microtiter Dish Biofilm Formation Assay

A 96 Well Microtiter Plate-based Method for Monitoring Formation and Antifungal Susceptibility Testing of Candida albicans Biofilms

Candida albicans remains the most frequent cause of fungal infections in an expanding population of compromised patients and candidiasis is now the third most common infection in US hospitals. Different manifestations of candidiasis are associated with biofilm formation, both on host tissues and/or medical devices (i.e. catheters). Biofilm formation carries negative clinical implications, as cells within the biofilms are protected from host immune responses and from the action of antifungals. We have developed a simple, fast and robust in vitro model for the formation of C. albicans biofilms using 96 well microtiter-plates, which can also be used for biofilm antifungal susceptibility testing. The readout of this assay is colorimetric, based on the reduction of XTT (a tetrazolium salt) by metabolically active fungal biofilm cells. A typical experiment takes approximately 24 h for biofilm formation, with an additional 24 h for antifungal susceptibility testing. Because of its simplicity and the use of commonly available laboratory materials and equipment, this technique democratizes biofilm research and represents an important step towards the standardization of antifungal susceptibility testing of fungal biofilms.

A 96 Well Microtiter Plate-based Method for Monitoring Formation and Antifungal Susceptibility Testing of Candida albicans Biofilms

We describe a simple, rapid and robust method for the formation of Candida albicans biofilms using 96 well microtiter plates and its utility in antifungal susceptibility testing of cells within biofilms.

A 96 de microtitulación y placa basada en el método para la formación de Control y pruebas de sensibilidad antifúngica Candida albicans Las biopelículas

Candida albicans remains the most frequent cause of fungal infections in an expanding population of compromised patients and candidiasis is now the third ...

Investigación

Inmunología e Infección

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological properties compared to free living microorganisms. Biofilms in nature are often difficult to investigate and reside under poorly defined conditions1. Using a transparent substratum it is possible to device a system where simple biofilms can be examined in a non-destructive way in real-time: here we demonstrate the assembly and operation of a flow cell model system, for in vitro 3D studies of microbial biofilms generating high reproducibility under well-defined conditions2,3.
The system consists of a flow cell that serves as growth chamber for the biofilm. The flow cell is supplied with nutrients and oxygen from a medium flask via a peristaltic pump and spent medium is collected in a waste container. This construction of the flow system allows a continuous supply of nutrients and administration of e.g. antibiotics with minimal disturbance of the cells grown in the flow chamber. Moreover, the flow conditions within the flow cell allow studies of biofilm exposed to shear stress. A bubble trapping device confines air bubbles from the tubing which otherwise could disrupt the biofilm structure in the flow cell.
The flow cell system is compatible with Confocal Laser Scanning Microscopy (CLSM) and can thereby provide highly detailed 3D information about developing microbial biofilms. Cells in the biofilm can be labeled with fluorescent probes or proteins compatible with CLSM analysis. This enables online visualization and allows investigation of niches in the developing biofilm. Microbial interrelationship, investigation of antimicrobial agents or the expression of specific genes, are of the many experimental setups that can be investigated in the flow cell system.

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Protocol describing the application of a flow cell system for growing and analyzing microbial biofilms for Confocal Laser Scanning Microscopy (CLSM).

Pseudomonas aeruginosa y Biofilm Saccharomyces cerevisiae en las celdas de flujo

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological ...

In vitro Biofilm Formation in an 8-well Chamber Slide

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. Biofilms are community-associated bacteria attached to a surface and encased in a matrix. The role of the extracellular matrix is multifaceted, including facilitating nutrient acquisition, and offers significant protection against environmental stresses (e.g. host immune responses). In an effort to acquire a better understanding as to how the bacteria within a biofilm respond to environmental stresses we have used a protocol wherein we visualize bacterial biofilms which have formed in an 8-well chamber slide. The biofilms were stained with the BacLight Live/Dead stain and examined using a confocal microscope to characterize the relative biofilm size, and structure under varying incubation conditions. Z-stack images were collected via confocal microscopy and analyzed by COMSTAT. This protocol can be used to help elucidate the mechanism and kinetics by which biofilms form, as well as identify components that are important to biofilm structure and stability.

In vitro Biofilm Formation in an 8-well Chamber Slide

This article describes the procedure for the formation and visualization of a bacterial biofilm grown within an 8-well chamber slide

En la formación de biofilm in vitro en una diapositiva Cámara de 8 pocillos

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. ...

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen interactions.&#160;The ease of obtaining large numbers of embryos, their accessibility due to external development, their optical transparency as well as the availability of a wide panoply of genetic/immunological tools and transgenic reporter line collections, contribute to the versatility of this model.&#160;In this respect, the present manuscript describes the use of zebrafish as an&#160;in vivo&#160;model system to investigate the chronology of Mycobacterium abscessus infection. This human pathogen can exist either as smooth (S) or rough (R) variants, depending on cell wall composition, and their respective virulence can be imaged and compared in zebrafish embryos and larvae. Micro-injection of either S or R fluorescent variants directly in the blood circulation via the caudal vein, leads to chronic or acute/lethal infections, respectively. This biological system allows high resolution visualization and analysis of the role of mycobacterial cording in promoting abscess formation. In addition, the use of fluorescent bacteria along with transgenic zebrafish lines harbouring fluorescent macrophages produces a unique opportunity for multi-color imaging of the host-pathogen interactions. This article describes detailed protocols for the preparation of homogenous M. abscessus inoculum and for intravenous injection of zebrafish embryos for subsequent fluorescence imaging of the interaction with macrophages. These techniques open the avenue to future investigations involving mutants defective in cord formation and are dedicated to understand how this impacts on M. abscessus pathogenicity in a whole vertebrate.

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Optically transparent zebrafish embryos are widely used to study and visualize in real time the interactions between pathogenic microorganisms and the innate immune cells. Micro-injection of Mycobacterium abscessus, combined with fluorescence imaging, is used to scrutinize essential pathogenic features such as cord formation in zebrafish embryos.

Descifrar e imagen Patogénesis y Cording de<em&gt; Abscessus Mycobacterium</em&gt; En embriones de pez cebra

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen ...

Targeting Biofilm Associated Staphylococcus aureus Using Resazurin Based Drug-susceptibility Assay

Most pathogenic bacteria are able to form biofilms during infection, but due to the difficulty of manipulating and assessing biofilms, the vast majority of laboratory work is conducted with planktonic cells. Here, we describe a peg plate biofilm assay as performed with Staphylococcus aureus. Bacterial biofilms are grown on pegs attached to a 96-well microtiter plate lid, washed through gentle submersion in buffer, and placed in a drug challenge plate. After subsequent incubation they are again washed and moved to a final recovery plate, in which the fluorescent dye resazurin serves as a viability indicator. This assay offers greatly increased ease-of-use, reliability, and reproducibility, as well as a wealth of data when conducted as a kinetic read. Moreover, this assay can be adapted to a medium-throughput drug screening approach by which an endpoint fluorescent readout is taken instead, offering a path for drug discovery efforts.

Targeting Biofilm Associated Staphylococcus aureus Using Resazurin Based Drug-susceptibility Assay

Most bacterial infections produce a biofilm. By virtue of their environment, biofilm associated bacteria are often phenotypically drug resistant. Novel antibacterial molecules that kill bacteria in biofilms are thus a high priority. We establish an assay to quickly screen for antimicrobial compounds that are effective at eradicating biofilms.

Orientación de Biofilm Asociadas<em&gt; Staphylococcus aureus</em&gt; Uso de Ensayo de susceptibilidad a fármacos Basado resazurina

Most pathogenic bacteria are able to form biofilms during infection, but due to the difficulty of manipulating and assessing biofilms, the vast majority ...

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM)

Phagocytosis is a mechanism used by specialized cells to internalize and eliminate microorganisms or cellular debris. It relies on profound rearrangements of the actin cytoskeleton that is the driving force for plasma membrane extension around the particle. In addition, efficient engulfment of large material relies on focal exocytosis of intracellular compartments. This process is highly dynamic and numerous molecular players have been described to have a role during phagocytic cup formation. The precise regulation in time and space of all of these molecules, however, remains elusive. In addition, the last step of phagosome closure has been very difficult to observe because inhibition by RNA interference or dominant negative mutants often results in stalled phagocytic cup formation. 
We have set up a dedicated experimental approach using total internal reflection fluorescence microscopy (TIRFM) combined with epifluorescence to monitor step by step the extension of pseudopods and their tips in a phagosome growing around a particle loosely bound to a coverslip. This method allows us to observe, with high resolution the very tips of the pseudopods and their fusion during closure of the phagosome in living cells for two different fluorescently tagged proteins at the same time.

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy TIRFM

We describe an experimental setup to visualize with unprecedented high resolution phagosome formation and closure in three dimensions in living macrophages, using total internal reflection fluorescence microscopy. It allows monitoring of the base of the phagocytic cup, the extending pseudopods, as well as the precise site of phagosome scission.

&quot;Fagosoma Cierre de ensayo&quot; para visualizar Fagosoma Formación en tres dimensiones utilizando la reflexión interna total fluorescente Microscopía (TIRFM)

Phagocytosis is a mechanism used by specialized cells to internalize and eliminate microorganisms or cellular debris. It relies on profound rearrangements ...

Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.

This protocol describes the visualization of biofilm development following exposure to host-factors using a slide chamber model. This model allows for direct visualization of biofilm development as well as analysis of biofilm parameters using computer software programs.

La visualización de los Efectos de esputo en el desarrollo del biofilm mediante un modelo de Septadas cubreobjetos

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the ...

Visualization of Biofilm Formation in Candida albicans Using an Automated Microfluidic Device

Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. albicans is its ability to form biofilms, structured communities of cells attached to biotic and abiotic surfaces. C. albicans biofilms can form on host tissues, such as mucosal layers, and on medical devices, such as catheters, pacemakers, dentures, and joint prostheses. Biofilms pose significant clinical challenges because they are highly resistant to physical and chemical perturbations, and can act as reservoirs to seed disseminated infections. Various in vitro assays have been utilized to study C. albicans biofilm formation, such as microtiter plate assays, dry weight measurements, cell viability assays, and confocal scanning laser microscopy. All of these assays are single end-point assays, where biofilm formation is assessed at a specific time point. Here, we describe a protocol to study biofilm formation in real-time using an automated microfluidic device under laminar flow conditions. This method allows for the observation of biofilm formation as the biofilm develops over time, using customizable conditions that mimic those of the host, such as those encountered in vascular catheters. This protocol can be used to assess the biofilm defects of genetic mutants as well as the inhibitory effects of antimicrobial agents on biofilm development in real-time.

Visualization of Biofilm Formation in Candida albicans Using an Automated Microfluidic Device

This protocol describes the use of a customizable automated microfluidic device to visualize biofilm formation in Candida albicans under host physiological conditions.

Visualización de la formación de Biofilm de Candida albicans utilizando un dispositivo microfluídico automatizado

Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. ...

Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification

Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, a significant stress response is induced during gastrointestinal transit and upon bile exposure, a normal component of human digestion. To overcome the bactericidal effects of bile, many enteric pathogens form a biofilm hypothesized to permit survival when transiting through the small intestine. Here we present methodologies to define biofilm formation through solid-phase adherence assays as well as extracellular polymeric substance (EPS) matrix detection and visualization. Furthermore, biofilm dispersion assessment is presented to mimic the analysis of events triggering release of bacteria during the infection process. Crystal violet staining is used to detect adherent bacteria in a high-throughput 96-well plate adherence assay. EPS production assessment is determined by two assays, namely microscopy staining of the EPS matrix and semi-quantitative analysis with a fluorescently-conjugated polysaccharide binding lectin. Finally, biofilm dispersion is measured through colony counts and plating. Positive data from multiple assays support the characterization of biofilms and can be utilized to identify bile salt-induced biofilm formation in other bacterial strains.

This protocol enables the reader to analyze bile salt-induced biofilm formation in enteric pathogens using a multifaceted approach to capture the dynamic nature of bacterial biofilms by assessing adherence, extracellular polymeric substance matrix formation, and dispersion.

Formación de biopelículas inducida por sales biliares en patógenos entéricos: técnicas para la identificación y cuantificación

Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, ...

A High-throughput Assay to Assess and Quantify Neutrophil Extracellular Trap Formation

Neutrophil extracellular traps (NETs) are immunogenic extracellular DNA structures that can be released by neutrophils upon a wide variety of triggers. NETs have been demonstrated to serve as an important host defense mechanism that traps and kills microorganisms. On the other hand, they have been implicated in diverse systemic autoimmune diseases. NETs are immunogenic and toxic structures that contain a pool of relevant autoantigens including anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) and systemic lupus erythematosus (SLE). Different forms of NETs can be induced depending on the stimulus. The amount of NETs can be quantified using different techniques including measuring DNA release in supernatants, measuring DNA-complexed with NET-molecules like myeloperoxidase (MPO) or neutrophil elastase (NE), measuring the presence of citrullinated histones by fluorescence microscopy, or flow cytometric detection of NET-components which all have different features regarding their specificity, sensitivity, objectivity, and quantity. Here is a protocol to quantify ex vivo NET formation in a highly-sensitive, high-throughput manner by using three-dimensional immunofluorescence confocal microscopy. This protocol can be applied to address various research questions about NET formation and degradation in health and disease.

This protocol describes a highly sensitive and high throughput neutrophil extracellular trap (NET) assay for the semi-automated quantification of ex vivo NET formation by immunofluorescence three-dimensional confocal microscopy. This protocol can be used to evaluate NET formation and degradation after different stimuli and can be used to study potential NET-targeted therapies.

Un análisis de alto rendimiento para evaluar y cuantificar la formación de neutrófilos trampa extracelular

Neutrophil extracellular traps (NETs) are immunogenic extracellular DNA structures that can be released by neutrophils upon a wide variety of triggers. ...