Queremos agradecer el apoyo del Reino Unido, el Instituto Nacional de Investigación en Salud, el Dr. Hadwen Fideicomiso para la Investigación Humana, la principal de financiación médica del Reino Unido organización benéfica de investigación exclusivamente técnicas sin animales de investigación para sustituir los experimentos con animales, y el Wellcome Trust (089.215 de subvención). También agradecemos a Novartis Pharmaceuticals UK Ltd (beca educativa sin restricciones).

<ol>
	<li>Andrews, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BSAC+standardized+disc+susceptibility+testing+method+(version+8).">BSAC standardized disc susceptibility testing method (version 8).</a> J. Antimicrob. Chemother. 64, 454-489 (2009).</li><li>Worlitzsch, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+reduced+mucus+oxygen+concentration+in+airway+Pseudomonas+infections+of+cystic+fibrosis+patients.">Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patients.</a> J. Clin. Invest. 109, 317-325 (2002).</li><li>Smith, A. L., Fiel, S. B., Mayer-Hamblett, N., Ramsey, B., Burns, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Susceptibility+testing+of+Pseudomonas+aeruginosa+isolates+and+clinical+response+to+parenteral+antibiotic+administration:+lack+of+association+in+cystic+fibrosis.">Susceptibility testing of Pseudomonas aeruginosa isolates and clinical response to parenteral antibiotic administration: lack of association in cystic fibrosis.</a> Chest. 123, 1495-1502 (2003).</li><li>Sriramulu, D. D., Lunsdorf, H., Lam, J. S., Romling, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcolony+formation:+a+novel+biofilm+model+of+Pseudomonas+aeruginosa+for+the+cystic+fibrosis+lung.">Microcolony formation: a novel biofilm model of Pseudomonas aeruginosa for the cystic fibrosis lung.</a> J. Med. Microbiol. 54, 667-676 (2005).</li><li>Garbe, J. <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+JG024,+a+pseudomonas+aeruginosa+PB1-like+broad+host+range+phage+under+simulated+infection+conditions.">Characterization of JG024, a pseudomonas aeruginosa PB1-like broad host range phage under simulated infection conditions.</a> BMC Microbiol. 10, 301 (2010).</li><li>Naughton, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+AES-1+exhibits+increased+virulence+gene+expression+during+chronic+infection+of+cystic+fibrosis+lung.">Pseudomonas aeruginosa AES-1 exhibits increased virulence gene expression during chronic infection of cystic fibrosis lung.</a> PLoS One. 6, e24526 (2011).</li><li>Moskowitz, S. M., Foster, J. M., Emerson, J. C., Gibson, R. L., Burns, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+Pseudomonas+biofilm+susceptibilities+to+assign+simulated+antibiotic+regimens+for+cystic+fibrosis+airway+infection.">Use of Pseudomonas biofilm susceptibilities to assign simulated antibiotic regimens for cystic fibrosis airway infection.</a> J. Antimicrob. Chemother. 56, 879-886 (2005).</li><li>Field, T. R., White, A., Elborn, J. S., Tunney, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+oxygen+limitation+on+the+in+vitro+antimicrobial+susceptibility+of+clinical+isolates+of+Pseudomonas+aeruginosa+grown+planktonically+and+as+biofilms.">Effect of oxygen limitation on the in vitro antimicrobial susceptibility of clinical isolates of Pseudomonas aeruginosa grown planktonically and as biofilms.</a> Eur. J. Clin. Microbiol. Infect. Dis. 24, 677-687 (2005).</li><li>Bjarnsholt, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+biofilms+in+the+respiratory+tract+of+cystic+fibrosis+patients.">Pseudomonas aeruginosa biofilms in the respiratory tract of cystic fibrosis patients.</a> Pediatr. Pulmonol. 44, 547-558 (2009).</li><li>Hill, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotic+susceptibilities+of+Pseudomonas+aeruginosa+isolates+derived+from+patients+with+cystic+fibrosis+under+aerobic,+anaerobic,+and+biofilm+conditions.">Antibiotic susceptibilities of Pseudomonas aeruginosa isolates derived from patients with cystic fibrosis under aerobic, anaerobic, and biofilm conditions.</a> J. Clin. Microbiol. 43, 5085-5090 (2005).</li><li>Fung, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+expression+of+Pseudomonas+aeruginosa+in+a+mucin-containing+synthetic+growth+medium+mimicking+cystic+fibrosis+lung+sputum.">Gene expression of Pseudomonas aeruginosa in a mucin-containing synthetic growth medium mimicking cystic fibrosis lung sputum.</a> J. Med. Microbiol. 59, 1089-1100 (2010).</li><li>Andrews, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BSAC+standardized+disc+susceptibility+testing+method+(version+8).">BSAC standardized disc susceptibility testing method (version 8).</a> The Journal of antimicrobial chemotherapy. 64, 454-489 (2009).</li><li>Rybtke, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+implication+of+Pseudomonas+aeruginosa+biofilms+in+infections.">The implication of Pseudomonas aeruginosa biofilms in infections.</a> Inflamm Allergy Drug Targets. 10, 141-157 (2011).</li><li>Moreau-Marquis, S., Stanton, B. A., 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=Pseudomonas+aeruginosa+biofilm+formation+in+the+cystic+fibrosis+airway.">Pseudomonas aeruginosa biofilm formation in the cystic fibrosis airway.</a> Pulm. Pharmacol. Ther. 21, 595-599 (2008).</li><li>Ahmed, S. A., Gogal, R. M., Walsh, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+rapid+and+simple+non-radioactive+assay+to+monitor+and+determine+the+proliferation+of+lymphocytes:+an+alternative+to+[3H]thymidine+incorporation+assay.">A new rapid and simple non-radioactive assay to monitor and determine the proliferation of lymphocytes: an alternative to [3H]thymidine incorporation assay.</a> J. Immunol. Methods. 170, 211-224 (1994).</li><li>Fothergill, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+antibiotic+treatment+on+bacteriophage+production+by+a+cystic+fibrosis+epidemic+strain+of+Pseudomonas+aeruginosa.">Effect of antibiotic treatment on bacteriophage production by a cystic fibrosis epidemic strain of Pseudomonas aeruginosa.</a> Antimicrob. Agents Chemother. 55, 426-428 (2011).</li><li>Singh, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quorum-sensing+signals+indicate+that+cystic+fibrosis+lungs+are+infected+with+bacterial+biofilms.">Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms.</a> Nature. 407, 762-764 (2000).</li><li>Mowat, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+Aeruginosa+Population+Diversity+and+Turnover+in+Cystic+Fibrosis+Chronic+Infections.">Pseudomonas Aeruginosa Population Diversity and Turnover in Cystic Fibrosis Chronic Infections.</a> Am. J. Respir. Crit. Care. Med. , (2011).</li><li>Fothergill, J. L., Mowat, E., Ledson, M. J., Walshaw, M. J., Winstanley, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluctuations+in+phenotypes+and+genotypes+within+populations+of+Pseudomonas+aeruginosa+in+the+cystic+fibrosis+lung+during+pulmonary+exacerbations.">Fluctuations in phenotypes and genotypes within populations of Pseudomonas aeruginosa in the cystic fibrosis lung during pulmonary exacerbations.</a> J. Med. Microbiol. 59, 472-481 (2010).</li><li>Fouhy, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusible+signal+factor-dependent+cell-cell+signaling+and+virulence+in+the+nosocomial+pathogen+Stenotrophomonas+maltophilia.">Diffusible signal factor-dependent cell-cell signaling and virulence in the nosocomial pathogen Stenotrophomonas maltophilia.</a> J. Bacteriol. 189, 4964-4968 (2007).</li><li>Winstanley, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newly+introduced+genomic+prophage+islands+are+critical+determinants+of+in+vivo+competitiveness+in+the+Liverpool+Epidemic+Strain+of+Pseudomonas+aeruginosa.">Newly introduced genomic prophage islands are critical determinants of in vivo competitiveness in the Liverpool Epidemic Strain of Pseudomonas aeruginosa.</a> Genome Res. 19, 12-23 (2009).</li><li>Carter, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+subtype+of+a+Pseudomonas+aeruginosa+cystic+fibrosis+epidemic+strain+exhibits+enhanced+virulence+in+a+murine+model+of+acute+respiratory+infection.">A subtype of a Pseudomonas aeruginosa cystic fibrosis epidemic strain exhibits enhanced virulence in a murine model of acute respiratory infection.</a> J. Infect. Dis. 202, 935-942 (2010).</li></ol>

No hay conflictos de interés declarado.

En este estudio se utilizó un novedoso modelo in vitro sobre la base de ASM para replicar P. condiciones aeruginosa biofilm en el pulmón de la FQ 4. El modelo se ha modificado correctamente a pequeña escala, de alto rendimiento de las pruebas de los agentes antimicrobianos. Los pasos críticos de este ensayo son: <ol><li> La preparación consistente de los medios de comunicación ASM y el mantenimiento de la esterilidad. Se ha dedicado largas horas para optimizar la forma en que se añade cada componente para obtener resultados reproducibles en todo momento. La filtración de la ASM es lento, pero es preferible a tratamiento en autoclave, lo cual puede dañar el componente de mucina. No recomendamos la adición de antibióticos, según lo sugerido por otros 11, porque esto puede imponer considerables presiones selectivas, las mutaciones de unidad, inducir la lisis profago 16 y altera significativamente la expresión de múltiples genes bacterianos. </li><li> El ensayo debe ser optimizado en función del volumen de Of ASM utilizado. Velocidades de agitación se aumentó para los pequeños volúmenes y un biofilm más corto ciclo de vida se observa. </li></ol> Una aplicación obvia del modelo de biofilm a pequeña escala ASM es la determinación más realista de las susceptibilidades a los antimicrobianos (biofilm BSMIC 90). Nichos anaeróbicos y microaerófilos están presentes en el pulmón CF y existe evidencia de que el oxígeno se limita profundamente dentro maduro biopelículas 2, 17. Aquí demostramos que el 10/14 P. clínica aeruginosa aisladas de pacientes con FQ presentan una considerable esputos (4 - ≥ 128 veces) disminución de la sensibilidad a la tobramicina en condiciones de microaerofilia en ASM. Los resultados de este estudio sugieren que los antibióticos, como la tobramicina, podría ser menos eficaz frente a P. infecciones aeruginosa en el pulmón con FQ que los indicados por los métodos convencionales de las pruebas de sensibilidad. Estos resultados reflejan los estudios previos sobre la susceptibilidad antimicrobiana de las biopelículas 10. Pequeñaescala de ensayos ASM por lo tanto ofrecer una plataforma sencilla de alto rendimiento para generar datos significativos de sensibilidad a los antibióticos para informar mejor a las decisiones terapéuticas. El ensayo se limita en la misma forma que las pruebas convencionales de susceptibilidad a los antibióticos en que las colonias individuales se recogen para la detección de que puede no ser representativa de toda la población. Sin embargo, creemos que un enfoque (i) que no se usen de la superficie del crecimiento del biofilm adjunto y (ii) aplicable a las condiciones de microaerofilia, representa una alternativa clara y una mejora potencial de los métodos existentes. Llegamos a la conclusión de que este ensayo es un modelo adecuado para estudiar P. poblaciones aeruginosa biofilm. La prueba adicional en el ámbito clínico que se dilucide si la susceptibilidad a antibióticos sobre la base de biofilm crecido P. aeruginosa podría dar lugar a diferentes opciones de antibióticos con potencial mejora de los resultados microbiológicos y clínicos. Investigaciones similares que utilizan los modelos clásicos de biofilm han demostrado que los valores BSMIC conducirdiferentes a las recomendaciones para el tratamiento con antibióticos 5,17. Además de las pruebas para la efectividad de los agentes anti-infecciosos, el sistema ASM representa una alternativa barata, simple y reproducible a los modelos animales para estudios tales como los destinados a la comprensión de la diversificación de la P. poblaciones aeruginosa. Hemos observado amplia heterogeneidad en las poblaciones naturales de P. aeruginosa recuperado de pacientes con CF esputos 18, 19. La diversificación fenotípica y genotípica similar se puede observar durante el crecimiento en ASM 4 (y nuestros datos no publicados), por lo que es un atractivo modelo in vitro de las enfermedades de los pulmones CF. La relativa simplicidad del modelo ASM facilita el diseño de experimentos a largo plazo de adaptación destinados, por ejemplo, en el seguimiento de los efectos de los antibióticos u otros estreses de la P. aeruginosa divergencia de la población. Además, otros patógenos bacterianos se puede cultivar enASM. Por ejemplo, Fouhy et al. 2007 han utilizado ASM para estudiar la formación del biofilm de S. maltophillia 20.

<table border="1"><tbody><tr><td> Nombre de reactivo </td><td> Empresa </td><td> Número de catálogo </td></tr><tr><td> ADN de esperma de pescado </td><td> Sigma-Aldrich </td><td> 74782 </td></tr><tr><td> La mucina del estómago porcino tipo II </td><td> Sigma-Aldrich </td><td> M2378 </td></tr><tr><td> L-Alanina </td><td> Acros Organics </td><td> 102830250 </td></tr><tr><td> L-Arginina </td><td> Sigma-Aldrich </td><td> A5006 </td></tr><tr><td> L (+)-asparagina monohidrato </td><td> Acros Organics </td><td> 175271000 </td></tr><tr><td> L (+)-aspártico ácido </td><td> Acros Organics </td><td> 105041000 </td></tr><tr><td> L-cisteína </td><td> Sigma-Aldrich </td><td> 168149 </td></tr&gt; <tr><td> L (+)-ácido glutámico </td><td> Acros Organics </td><td> 156211000 </td></tr><tr><td> L-glutamina </td><td> Sigma-Aldrich </td><td> G3126 </td></tr><tr><td> Glicina </td><td> Acros Organics </td><td> 220911000 </td></tr><tr><td> L-histidina </td><td> Sigma-Aldrich </td><td> H8000 </td></tr><tr><td> L-isoleucina </td><td> Sigma-Aldrich </td><td> I2752 </td></tr><tr><td> L-leucina </td><td> Sigma-Aldrich </td><td> L8000 </td></tr><tr><td> L (+)-lisina monohidrocloruro </td><td> Acros Organics </td><td> 125222500 </td></tr><tr><td> L-Metionina </td><td> Sigma-Aldrich </td><td> M9625 </td></tr><tr><td> L-fenilalanina </td><td> Acros Organics </td><td> 130310250 </td></tr><tr><td> L-prolina </td><td> Sigma-Aldrich </td><td> P0380 </td></tr><tr><td> L-serina </td><td> Acros Organics </td><td> 132660250 </td></tr><tr><td> L-treonina </td><td> Acros Organics </td><td> 138930250 </td></tr><tr><td> L (-)-triptófano </td><td> Acros Organics </td><td> 140590250 </td></tr><tr><td> L-Tirosina </td><td> Acros Organics </td><td> 140641000 </td></tr><tr><td> L-valina </td><td> Sigma-Aldrich </td><td> V0500 </td></tr><tr><td> Ácido dietilentriaminopentaacético </td><td> Sigma-Aldrich </td><td> 32318 </td></tr><tr><td> NaCl </td><td> Fisher Scientific </td><td> S/3160/60 </td></tr><tr><td> KCl </td><td> BDH </td><td> BDH0258 </td></tr><tr><td&gt; KOH </td><td> BDH </td><td> BDH0262 </td></tr><tr><td> La yema de huevo de emulsión </td><td> Sigma-Aldrich </td><td> 17148 </td></tr><tr><td> ME 2 bomba de vacío de diafragma </td><td> Vacuubrand </td><td> 696126 </td></tr><tr><td> Steritop filtros (tamaño de poro: 0,22 m, el tamaño del cuello: 45 mm) </td><td> Millipore </td><td> SCGPT10RE </td></tr><tr><td> Medio Luria-Bertani </td><td> Sigma </td><td> L2897 </td></tr><tr><td> Placas de 96 pocillos de microtitulación </td><td> Sarstedt </td><td> 82.1581 </td></tr><tr><td> De 24 pocillos de cultivo de tejidos tratados con placas </td><td> Iwaki </td><td> 3820-024 </td></tr><tr><td> CampyGen paquetes de generación de gas </td><td> Oxoid </td><td> CN0025 </td></tr><tr><td> Cámara de microaerofílico </td><td> Oxoid </td><td> HP0011 </td></tr><tr><td> Tobramicina sulfato </td><td> Sigma-Aldrich </td><td> T1783 </td></tr><tr><td> Celulasa, de Aspergillus niger </td><td> Sigma-Aldrich </td><td> 22178 </td></tr><tr><td> Resazurina </td><td> Sigma-Aldrich </td><td> 199303 </td></tr><tr><td> Citrate.H 2 0 </td><td> BDH </td><td> BDH0288 </td></tr><tr><td> Fluostar omega lector de microplacas </td><td> BMG-Labtech </td><td> SPECTROstar Omega </td></tr></tbody></table>

use of artificial sputum medium to test antibiotic efficacy against pseudomonas aeruginosa in conditions more relevant to the cystic fibrosis lung

Existe una preocupación creciente acerca de la pertinencia de las pruebas in vitro sensibilidad a los antimicrobianos cuando se aplica a los aislamientos de P. aeruginosa en la fibrosis quística (FQ). Los métodos existentes se basan en una sola o unas pocas cepas cultivadas aeróbicamente y planktonically. Predeterminados valores de corte se utilizan para definir si las bacterias son sensibles o resistentes a cualquier antibiótico que se administra 1. Sin embargo, durante las infecciones crónicas de los pulmones en pacientes con FQ, P. poblaciones aeruginosa existen en biopelículas y existe evidencia de que el medio ambiente es en gran parte microaerofílico 2. La gran diferencia en las condiciones entre las bacterias en el pulmón y los que durante las pruebas de diagnóstico ha puesto en duda la pertinencia fiabilidad e incluso una de estas 3 pruebas. Medio artificial de esputo (ASM) es un medio de cultivo que contiene los componentes de esputo de pacientes con FQ, incluyendo aminoácidos y el ADN, la mucina libre. P. aeruginosa &lt;/ Em&gt; crecimiento en el crecimiento de imitadores ASM durante las infecciones CF, con la formación de estructuras de auto-agregación de biofilm y la divergencia de la población 4,5,6. El objetivo de este estudio fue desarrollar un ensayo de microtitulación de placa para estudiar la susceptibilidad antimicrobiana de P. aeruginosa basado en el crecimiento en ASM, que es aplicable a ambas condiciones microaerófilas y aeróbica. Un ensayo ASM se desarrolló en un formato de placa de microtitulación. P biopelículas aeruginosa se ​​dejaron desarrollar durante 3 días antes de la incubación con los agentes antimicrobianos a diferentes concentraciones durante 24 horas. Después de la interrupción del biofilm, la viabilidad celular se midió mediante la tinción con resazurina. Este ensayo se utilizó para determinar la concentración de células mínima inhibitoria sésiles (SMIC) de tobramicina por 15 diferentes P. aeruginosa bajo condiciones aeróbicas y microaerófilos y valores SMIC se compararon con los obtenidos con el crecimiento caldo estándar. Si bien no fuealguna evidencia de aumento de los valores de CIM para aislamientos cultivados en ASM, en comparación con sus homólogos planctónicas, las mayores diferencias se encontraron con las bacterias ensayadas en condiciones de microaerofilia, que mostraron una resistencia mucho mayor, hasta un&gt; 128 veces, hacia la tobramicina en el sistema de ASM, cuando en comparación con los ensayos llevados a cabo en condiciones aerobias. La falta de asociación entre los actuales métodos de ensayo de la susceptibilidad y la evolución clínica ha puesto en duda la validez de los métodos actuales 3. Varios modelos in vitro se han utilizado previamente para estudiar P. biopelículas aeruginosa 7, 8. Sin embargo, estos métodos se basan en las biopelículas superficie adjuntos, mientras que las biopelículas ASM se asemejan a los observados en el pulmón CF 9. Además, la concentración de oxígeno reducida en el moco se ha demostrado que altera el comportamiento de P. aeruginosa 2 y afectar a la susceptibilidad antibiótica 10. Por lo tanto using ASM en condiciones de microaerofilia puede proporcionar un entorno más realista en el que el estudio de susceptibilidad antimicrobiana.

Watch this Scientific Journal Video about Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung at JoVE.com

Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

Las pruebas de diagnóstico actual sensibilidad a los antimicrobianos se basa en el crecimiento de plancton de las cepas en condiciones de nutrientes ricos y aeróbicas. En este caso, contamos con un medio alternativo de esputo artificiales para estudiar la susceptibilidad antimicrobiana de las biopelículas de Pseudomonas aeruginosa, tanto en condiciones aeróbicas y microaerófilos más representativos de la fibrosis quística pulmonar.

Uso de un medio artificial de esputo para probar la eficacia de antibióticos contra la<em&gt; Pseudomonas aeruginosa</em&gt; En condiciones más pertinentes a la fibrosis quística pulmonar

There  is growing concern about the relevance of in vitro antimicrobial  susceptibility tests when applied to isolates of P. aeruginosa from  cystic ...

use-artificial-sputum-medium-to-test-antibiotic-efficacy-against

Research

JoVE Journal

Immunology and Infection

Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

32.5K vistas.  University of Liverpool. Las pruebas de diagnóstico actual sensibilidad a los antimicrobianos se basa en el crecimiento de plancton de las cepas en condiciones de nutrientes ricos y aeróbicas. En este caso, contamos con un medio alternativo de esputo artificiales para estudiar la susceptibilidad antimicrobiana de las biopelículas de Pseudomonas aeruginosa, tanto en condiciones aeróbicas y microaerófilos más representativos de la fibrosis quística pulmonar.

Video: Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

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 ...

Investigación

Inmunología e Infección

RNA Isolation of Pseudomonas aeruginosa Colonizing the Murine Gastrointestinal Tract

Pseudomonas aeruginosa (PA) infections result in significant morbidity and mortality in hosts with compromised immune systems, such as patients with leukemia, severe burn wounds, or organ transplants1. In patients at high-risk for developing PA bloodstream infections, the gastrointestinal (GI) tract is the main reservoir for colonization2, but the mechanisms by which PA transitions from an asymptomatic colonizing microbe to an invasive, and often deadly, pathogen are unclear. Previously, we performed in vivo transcription profiling experiments by recovering PA mRNA from bacterial cells residing in the cecums of colonized mice 3 in order to identify changes in bacterial gene expression during alterations to the host&#x2019;s immune status.
As with any transcription profiling experiment, the rate-limiting step is in the isolation of sufficient amounts of high quality mRNA. Given the abundance of enzymes, debris, food residues, and particulate matter in the GI tract, the challenge of RNA isolation is daunting. Here, we present a method for reliable and reproducible isolation of bacterial RNA recovered from the murine GI tract. This method utilizes a well-established murine model of PA GI colonization and neutropenia-induced dissemination4. Once GI colonization with PA is confirmed, mice are euthanized and cecal contents are recovered and flash frozen. RNA is then extracted using a combination of mechanical disruption, boiling, phenol/chloroform extractions, DNase treatment, and affinity chromatography. Quantity and purity are confirmed by spectrophotometry (Nanodrop Technologies) and bioanalyzer (Agilent Technologies) (Fig 1). This method of GI microbial RNA isolation can easily be adapted to other bacteria and fungi as well.

RNA Isolation of Pseudomonas aeruginosa Colonizing the Murine Gastrointestinal Tract

A reliable method for the RNA isolation of Pseudomonas aeruginosa recovered from murine cecums is described. The RNA recovered is of sufficient quantity and quality for subsequent qPCR, transcription profiling, and RNA Seq experiments. This technique can be adapted for RNA isolation of other intestinal microbes.

El aislamiento de ARN Pseudomonas aeruginosa Que colonizan el tracto gastrointestinal murino

Pseudomonas aeruginosa (PA) infections result in significant morbidity and mortality in hosts with compromised immune systems, such as patients with ...

Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

A mouse model of chronic airway infection is a key asset in cystic fibrosis (CF) research, although there are a number of concerns regarding the model itself. Early phases of inflammation and infection have been widely studied by using the Pseudomonas aeruginosa agar-beads mouse model, while only few reports have focused on the long-term chronic infection in vivo. The main challenge for long term chronic infection remains the low bacterial burden by P. aeruginosa and the low percentage of infected mice weeks after challenge, indicating that bacterial cells are progressively cleared by the host.
This paper presents a method for obtaining efficient long-term chronic infection in mice. This method is based on the embedding of the P. aeruginosa clinical strains in the agar-beads in vitro, followed by intratracheal instillation in C57Bl/6NCrl mice. Bilateral lung infection is associated with several measurable read-outs including weight loss, mortality, chronic infection, and inflammatory response. The P. aeruginosa RP73 clinical strain was preferred over the PAO1 reference laboratory strain since it resulted in a comparatively lower mortality, more severe lesions, and higher chronic infection. P. aeruginosa colonization may persist in the lung for over three months. Murine lung pathology resembles that of CF patients with advanced chronic pulmonary disease.
This murine model most closely mimics the course of the human disease and can be used both for studies on the pathogenesis and for the evaluation of novel therapies.

Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

We describe the agar-beads method to establish persistent long-term chronic Pseudomonas aeruginosa airway infection in the mouse model.

Crónica a largo plazo<em&gt; Pseudomonas aeruginosa</em&gt; Infección de las vías respiratorias en los ratones

A mouse model of chronic airway infection is a key asset in cystic fibrosis (CF) research, although there are a number of concerns regarding the model ...

Pseudomonas aeruginosa Induced Lung Injury Model

In order to study human acute lung injury and pneumonia, it is important to develop animal models to mimic various pathological features of this disease. Here we have developed a mouse lung injury model by intra-tracheal injection of bacteria Pseudomonas aeruginosa (P. aeruginosa or PA). Using this model, we were able to show lung inflammation at the early phase of injury. In addition, alveolar epithelial barrier leakiness was observed by analyzing bronchoalveolar lavage (BAL); and alveolar cell death was observed by Tunel assay using tissue prepared from injured lungs. At a later phase following injury, we observed cell proliferation required for the repair process. The injury was resolved 7 days from the initiation of P. aeruginosa injection. This model mimics the sequential course of lung inflammation, injury and repair during pneumonia. This clinically relevant animal model is suitable for studying pathology, mechanism of repair, following acute lung injury, and also can be used to test potential therapeutic agents for this disease.

Pseudomonas aeruginosa Induced Lung Injury Model

We have developed a mouse lung injury model by intra-tracheal injection of bacteria Pseudomonas aeruginosa. This model mimics lung injury during pneumonia and is clinically relevant.

Pseudomonas aeruginosa inducida por la lesión pulmonar Modelo

In order to study human acute lung injury and pneumonia, it is important to develop animal models to mimic various pathological features of this disease. ...

A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or A. baumannii

Efficacy of candidate antibacterial treatments must be demonstrated in animal models of infection as part of the discovery and development process, preferably in models which mimic the intended clinical indication. A method for inducing robust lung infections in immunocompetent rats and mice is described which allows for the assessment of treatments in a model of serious pneumonia caused by S. pneumoniae, H. influenzae, P. aeruginosa, K. pneumoniae or A. baumannii. Animals are anesthetized, and an agar-based inoculum is deposited deep into the lung via nonsurgical intratracheal intubation. The resulting infection is consistent, reproducible, and stable for at least 48 h and up to 96 h for most isolates. Studies with marketed antibacterials have demonstrated good correlation between in vivo efficacy and in vitro susceptibility, and concordance between pharmacokinetic/pharmacodynamic targets determined in this model and clinically accepted targets has been observed. Although there is an initial time investment when learning the technique, it can be performed quickly and efficiently once proficiency is achieved. Benefits of the model include elimination of the neutropenic requirement, increased robustness and reproducibility, ability to study more pathogens and isolates, improved flexibility in study design and establishment of a challenging infection in an immunocompetent host.

A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or  A. baumannii

A method for establishing lung infections in immunocompetent rodents is described. With proficiency, this method can be performed quickly and easily to induce stable infection with many isolates of S. pneumoniae, H. influenzae, P. aeruginosa, K. pneumoniae and A. baumannii.

Un modelo de neumonía en inmunocompetentes robusta roedores para evaluar Eficacia antibacteriana contra<i&gt; S. pneumoniae</i&gt;,<i&gt; H. influenzae</i&gt;,<i&gt; K. pneumoniae</i&gt;,<em&gt; P. aeruginosa</em&gt; o<em&gt; A. baumannii</em

Efficacy of candidate antibacterial treatments must be demonstrated in animal models of infection as part of the discovery and development process, ...

An IL-8 Transiently Transgenized Mouse Model for the In Vivo Long-term Monitoring of Inflammatory Responses

Airway inflammation is often associated with bacterial infections and represents a major determinant of lung disease. The in vivo determination of the pro-inflammatory capabilities of various factors is challenging and requires terminal procedures, such as bronchoalveolar lavage and the removal of lungs for in situ analysis, precluding longitudinal visualization in the same mouse. Here, lung inflammation is induced through the intratracheal instillation of Pseudomonas aeruginosa culture supernatant (SN) in transiently transgenized mice expressing the luciferase reporter gene under the control of a heterologous IL-8 bovine promoter. Luciferase expression in the lung is monitored by in vivo bioluminescent image (BLI) analysis over a 2.5- to 48-h timeframe following the instillation. The procedure can be repeated multiple times within 2 - 3 months, thus permitting the evaluation of the inflammatory response in the same mice without the need to terminate the animals. This approach permits the monitoring of pro- and anti-inflammatory factors acting in the lung in real time and appears suitable for functional and pharmacological studies.

An IL-8 Transiently Transgenized Mouse Model for the In Vivo Long-term Monitoring of Inflammatory Responses

The method described here allows for the visualization of IL-8 promoter-dependent inflammation activation in the lungs of mice through non-invasive bioluminescence imaging (BLI). The same animal can be subjected to BLI multiple times for up to two months from the time of delivery of the luciferase reporter construct.

Un modelo de ratón IL-8 transgénicamente transgéni-<em&gt; In Vivo</em&gt; Monitoreo a Largo Plazo de las Respuestas Inflamatorias

Airway inflammation is often associated with bacterial infections and represents a major determinant of lung disease. The in vivo determination of the ...

A Method to Test the Efficacy of Handwashing for the Removal of Emerging Infectious Pathogens

Handwashing is widely recommended to prevent infectious disease transmission. However, little comparable evidence exists on the efficacy of handwashing methods in general. Additionally, little evidence exists comparing handwashing methods to determine which are most efficacious at removing infectious pathogens. Research is needed to provide evidence for the different approaches to handwashing that may be employed during infectious disease outbreaks. Here, a laboratory method to assess the efficacy of handwashing methods at removing microorganisms from hands and their persistence in rinse water is described. Volunteers' hands are first spiked with the test organism and then washed with each handwashing method of interest. Generally, surrogate microorganisms are used to protect human subjects from disease. The number of organisms remaining on volunteers' hands after washing is tested using a modified "glove juice" method: the hands are placed in gloves with an eluent and are scrubbed to suspend the microorganisms and make them available for analysis by membrane filtration (bacteria) or plaque assay (viruses/bacteriophages). Rinse water produced from the handwashing is directly collected for analysis. Handwashing efficacy is quantified by comparing the log reduction value between samples taken after handwashing to samples with no handwashing. Rinse water persistence is quantified by comparing rinse water samples from various handwashing methods to samples collected after handwashing with just water. While this method is limited by the need to use surrogate organisms to preserve the safety of human volunteers, it captures aspects of handwashing that are difficult to replicate in an in vitro study and fills research gaps on handwashing efficacy and the persistence of infectious organisms in rinse water.

Handwashing is widely recommended to prevent infectious disease transmission. However, there is little evidence on which handwashing methods are most efficacious at removing infectious disease pathogens. We developed a method to assess the efficacy of handwashing methods at removing microorganisms.

Un método para probar la eficacia del lavado de manos para la eliminación de patógenos infecciosos emergentes

Handwashing is widely recommended to prevent infectious disease transmission. However, little comparable evidence exists on the efficacy of handwashing ...

Methods for Detecting Cytotoxic Amyloids Following Infection of Pulmonary Endothelial Cells by Pseudomonas aeruginosa

Patients who survive pneumonia have elevated death rates in the months following hospital discharge. It has been hypothesized that infection of pulmonary tissue during pneumonia results in the production of long-lived cytotoxins that can lead to subsequent end organ failure. We have developed in vitro assays to test the hypothesis that cytotoxins are produced during pulmonary infection. Isolated rat pulmonary endothelial cells and the bacterium Pseudomonas aeruginosa are used as model systems, and the production of cytoxins following infection of the endothelial cells by the bacteria is demonstrated using cell culture followed by direct quantitation using lactate dehydrogenase assays and a novel microscopic method utilizing ImageJ technology. The amyloid nature of these cytotoxins was demonstrated by thioflavin T binding assays and by immunoblotting and immunodepletion using A11 anti-amyloid antibody. Further analyses using immunoblotting demonstrated that oligomeric tau and A&#946; were produced and released by endothelial cells following infection by P. aeruginosa. These methods should be readily adaptable to analyses of human clinical samples.

Methods for Detecting Cytotoxic Amyloids Following Infection of Pulmonary Endothelial Cells by Pseudomonas aeruginosa

Simple methods are described for demonstrating the production of cytotoxic amyloids following infection of pulmonary endothelium by Pseudomonas aeruginosa.

Métodos para la detección de amiloides siguiente infección de pulmonar endotelial células citotóxicas por Pseudomonas aeruginosa

Patients who survive pneumonia have elevated death rates in the months following hospital discharge. It has been hypothesized that infection of pulmonary ...

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos

Antimicrobial resistance, a major consequence of diagnostic uncertainty and antimicrobial overprescription, is an increasingly recognized cause of severe infections, complications, and mortality worldwide with a huge impact on our society and on the health system. In particular, patients with compromised immune systems or pre-existing and chronic pathologies, such as cystic fibrosis (CF), are subjected to frequent antibiotic treatments to control the infections with the appearance and diffusion of multidrug resistant isolates. Therefore, there is an urgent need to address alternative therapies to counteract bacterial infections. Use of bacteriophages, the natural enemies of bacteria, can be a possible solution. The protocol detailed in this work describes the application of phage therapy against Pseudomonas aeruginosa infection in CF zebrafish embryos. Zebrafish embryos were infected with P. aeruginosa to demonstrate that phage therapy is effective against P. aeruginosa infections as it reduces lethality, bacterial burden and pro-inflammatory immune response in CF embryos.

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos

Presented here is a protocol for Pseudomonas aeruginosa infection and phage therapy application in cystic fibrosis (CF) zebrafish embryos.

Aplicación de terapia de phage para contrarrestar la infección por Pseudomonas aeruginosa en embriones de peces cebra de fibrosis quística

Antimicrobial resistance, a major consequence of diagnostic uncertainty and antimicrobial overprescription, is an increasingly recognized cause of severe ...

Visualization of Pseudomonas aeruginosa within the Sputum of Cystic Fibrosis Patients

Early detection and eradication of Pseudomonas aeruginosa within the lungs of cystic fibrosis patients can reduce the chance of developing chronic infection. The development of chronic P. aeruginosa infections is associated with a decline in lung function and increased morbidity. Therefore, there is a great interest in elucidating the reasons for the failure to eradicate P. aeruginosa with antibiotic therapy which occurs in approximately 10-40% of pediatric patients. One of many factors that can affect host clearance of P. aeruginosa and antibiotic susceptibility is variations in spatial organization (such as aggregation or biofilm formation) and polysaccharide production. Therefore, we were interested in visualizing the in situ characteristics of P. aeruginosa within the sputum of CF patients. A tissue clearing technique was applied to sputum samples after embedding the samples into a hydrogel matrix to retain the 3D structures relative to host cells. After tissue clearing, fluorescent labels and dyes were added to allow visualization. Fluorescence in situ hybridization was performed for the visualization of bacterial cells, binding of fluorescently labeled anti-Psl-antibodies for the visualization of the exopolysaccharide and DAPI staining to stain host cells to obtain structural insight. These methods allowed for the high-resolution imaging of P. aeruginosa within the sputum of CF patients via confocal laser scanning microscopy.

Visualization of Pseudomonas aeruginosa within the Sputum of Cystic Fibrosis Patients

This protocol provides methods for visualization of bacterial cells and polysaccharide synthesis locus (Psl) polysaccharide within the sputum of cystic fibrosis patients.