Riconosciamo l&#39;appoggio del Regno Unito Istituto Nazionale per la Ricerca sulla Salute, il Dr. Hadwen Trust per la ricerca umanistici, della britannica leader di finanziamento carità di ricerca medica senza animali esclusivamente tecniche di ricerca per sostituire gli esperimenti su animali, e il Wellcome Trust (Grant 089.215). Riconosciamo inoltre Novartis Pharmaceuticals UK Ltd (educazionale di sovvenzione).

<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>

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In questo studio abbiamo utilizzato un nuovo modello in vitro sulla base di ASM per replicare P. biofilm condizioni aeruginosa all&#39;interno del polmone CF 4. Il modello è stato modificato con successo per la piccola, high-throughput test di agenti antimicrobici. I passaggi critici di questo test sono: <ol><li> Preparazione costante dei mezzi di comunicazione ASM e sterilità mantenimento. Abbiamo dedicato lunghe ore per ottimizzare il modo in cui viene aggiunto ogni componente di ottenere risultati riproducibili ogni volta. Filtrazione della ASM è lento, ma è preferibile alla sterilizzazione in autoclave, che può danneggiare il componente mucina. Noi non consigliamo l&#39;aggiunta di antibiotici, come suggerito da altri 11, perché questo può comportare notevoli pressioni selettive, mutazioni di unità, indurre la lisi profago 16 e altera in modo significativo l&#39;espressione di più geni batterici. </li><li> Il dosaggio deve essere ottimizzata in base al volume of ASM utilizzato. Shaking velocità sono aumentati per i minori volumi e di un biofilm più breve ciclo di vita si osserva. </li></ol> Un&#39;applicazione evidente del modello di piccola scala biofilm ASM è la determinazione più realistica di suscettibilità biofilm BSMIC antimicrobici (90). Nicchie anaerobici e microaerofili sono presenti nel polmone CF e vi sono prove che l&#39;ossigeno è limitata nel profondo del biofilm maturo 2, 17. Qui si dimostra che 10/14 clinica P. aeruginosa isolati da pazienti Sputa CF presentano una notevole (4 - ≥ 128 volte) diminuzione della sensibilità alla tobramicina in condizioni microaerofili in ASM. I risultati di questo studio suggeriscono che antibiotici, come tobramicina, potrebbero essere meno efficaci contro P. aeruginosa nei polmoni CF quelli indicati con i metodi convenzionali test di sensibilità. Questi risultati riflettono gli studi precedenti sulla sensibilità agli antibiotici di biofilm 10. Small-scala saggi ASM quindi fornire una piattaforma semplice, ad alto rendimento per la generazione di significativi dati di sensibilità agli antibiotici per informare meglio le decisioni terapeutiche. Il saggio è limitata nello stesso modo convenzionale test di sensibilità agli antibiotici in singole colonie che vengono prelevati per lo screening che non può essere rappresentativa della popolazione. Tuttavia, riteniamo che un approccio (i) con superficie di crescita non collegato biofilm e (ii) applicabile alle condizioni microaerofili, rappresenta un&#39;alternativa chiara e un potenziale miglioramento dei metodi esistenti. Concludiamo che questo test è un modello adeguato per lo studio P. aeruginosa biofilm popolazioni. Ulteriori test in ambito clinico sarebbe verificare se suscettibilità agli antibiotici basata su biofilm cresciuti P. aeruginosa potrebbe portare a scelte diverse con antibiotici potenzialmente migliori esiti clinici e microbiologici. Indagini simili che utilizzano modelli di biofilm classici hanno dimostrato che i valori BSMIC portarealle raccomandazioni diverse per il trattamento antibiotico 5,17. Oltre al test per l&#39;efficacia delle agenti anti-infettivi, il sistema ASM rappresenta un buon mercato, un&#39;alternativa semplice e riproducibile per modelli animali per studi come quelli che mirano a comprendere la diversificazione delle P. aeruginosa popolazioni. Abbiamo osservato vasta eterogeneità nelle popolazioni naturali di P. aeruginosa recuperato dal paziente Sputa CF 18, 19. Simile la diversificazione fenotipica e genotipica può essere osservato durante la crescita in ASM 4 (ed i nostri dati non pubblicati), che lo rende un interessante modello in vitro delle condizioni polmonari CF. La relativa semplicità del modello ASM rende facile progettare esperimenti a lungo termine adattamento destinato, ad esempio, a monitorare gli effetti degli antibiotici o altre sollecitazioni su P. aeruginosa popolazione divergenza. Inoltre, altri patogeni batterici possono essere coltivate inASM. Ad esempio, Fouhy et al. ASM 2007 hanno utilizzato per studiare la formazione di biofilm da S. maltophillia 20.

<table border="1"><tbody><tr><td> Nome di reagente </td><td> Azienda </td><td> Numero di catalogo </td></tr><tr><td> DNA di sperma di pesce </td><td> Sigma-Aldrich </td><td> 74782 </td></tr><tr><td> Mucin da suini allo stomaco, di 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 monoidrato </td><td> Acros Organics </td><td> 175271000 </td></tr><tr><td> L (+)-acido aspartico </td><td> Acros Organics </td><td> 105041000 </td></tr><tr><td> L-cisteina </td><td> Sigma-Adrich </td><td> 168149 </td></tr&gt; <tr><td> L (+)-acido glutammico </td><td> Acros Organics </td><td> 156211000 </td></tr><tr><td> L-Glutammina </td><td> Sigma-Aldrich </td><td> G3126 </td></tr><tr><td> Glycine </td><td> Acros Organics </td><td> 220911000 </td></tr><tr><td> L-Istidina </td><td> Sigma-Adrich </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 monocloridrato </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 (-)-Triptofano </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> L&#39;acido Diethylenetriaminepentaacetic </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> Emulsione di tuorlo d&#39;uovo </td><td> Sigma-Aldrich </td><td> 17148 </td></tr><tr><td> ME 2 pompa a vuoto a membrana </td><td> Vacuubrand </td><td> 696126 </td></tr><tr><td> Steritop filtri (diametro dei pori: 0,22 micron, la dimensione del collo: 45 mm) </td><td> Millipore </td><td> SCGPT10RE </td></tr><tr><td> Luria-Bertani mezzo </td><td> Sigma </td><td> L2897 </td></tr><tr><td> 96 pozzetti microtitolazione piastre </td><td> Sarstedt </td><td> 82,1581 </td></tr><tr><td> 24 pozzetti di coltura di tessuti trattati con piastre </td><td> Iwaki </td><td> 3820-024 </td></tr><tr><td> CampyGen generazione di gas confezioni </td><td> Oxoid </td><td> CN0025 </td></tr><tr><td> Camera microaerofilo </td><td> Oxoid </td><td> HP0011 </td></tr><tr><td> Tobramicina solfato </td><td> Sigma-Aldrich </td><td> T1783 </td></tr><tr><td> Cellulasi, da 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 lettore di micropiastre </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

Vi è una crescente preoccupazione per la rilevanza dei test di sensibilità in vitro agli antimicrobici quando applicata a isolati di P. aeruginosa da fibrosi cistica (CF) pazienti. Metodi esistenti contare su uno o alcuni isolati coltivati ​​aerobicamente e planktonically. Predeterminate cut-off sono utilizzati per definire se i batteri sono sensibili o resistenti a qualsiasi antibiotico somministrato 1. Tuttavia, durante le infezioni polmonari croniche in CF, P. popolazioni aeruginosa esistono in biofilm e vi sono prove che l&#39;ambiente è in gran parte microaerofilo 2. La netta differenza di condizioni tra i batteri nel polmone e quelli durante i test diagnostici ha messo in discussione l&#39;affidabilità e la rilevanza anche di questi test 3. Media espettorato artificiale (ASM) è un terreno di coltura contenente i componenti di espettorato dei pazienti CF, tra cui aminoacidi, mucina e il DNA libero. P. aeruginosa &lt;/ Em&gt; Crescita in ASM crescita mimica durante le infezioni CF, con la formazione di auto-aggregazione di strutture biofilm e divergenza della popolazione 4,5,6. Lo scopo di questo studio era di sviluppare un microtitolazione-piastra di analisi per studiare sensibilità agli antibiotici di P. aeruginosa basata sulla crescita in ASM, che è applicabile a queste due condizioni microaerofili e aerobica. Un saggio di ASM è stato sviluppato in un formato micropiastra. P. biofilm aeruginosa sono stati lasciati sviluppare per 3 giorni prima dell&#39;incubazione con agenti antimicrobici a diverse concentrazioni per 24 ore. Dopo l&#39;interruzione biofilm, la vitalità cellulare è stata misurata mediante colorazione con resazurina. Questo test è stato utilizzato per accertare la sessile concentrazione minima inibitoria delle cellule (SMIC) di tobramicina per 15 differenti P. aeruginosa isolati in condizioni aerobiche e microaerofili SMIC ei valori sono stati confrontati con quelli ottenuti con brodo di crescita standard. Mentre non vi eraalcune prove per i valori di MIC maggiori per isolati coltivati ​​in ASM rispetto ai loro omologhi planctonici, le maggiori differenze sono state trovate con i batteri testati in condizioni microaerofili, che hanno mostrato una resistenza molto aumentata fino ad un&gt; 128 volte, verso tobramicina nel sistema ASM, quando rispetto ai saggi effettuati in condizioni aerobiche. La mancanza di associazione tra i metodi attuali test di sensibilità e risultati clinici ha messo in dubbio la validità dei metodi attuali 3. Vari modelli in vitro sono stati utilizzati precedentemente per studiare P. biofilm aeruginosa 7, 8. Tuttavia, questi metodi si basa su biofilm di superficie collegati, mentre i biofilm ASM simili a quelli osservati nel polmone CF 9. Inoltre, la concentrazione di ossigeno ridotto nel muco è stato dimostrato che alterano il comportamento di P. aeruginosa 2 e pregiudica la suscettibilità agli antibiotici 10. Pertanto using ASM in condizioni microaerofili può fornire un ambiente più realistico in cui studiare sensibilità agli antibiotici.

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

Current test diagnostici di sensibilità agli antibiotici si basa sulla crescita planctoniche di isolati in ricchi di nutrienti, le condizioni aerobiche. Qui, ci avvaliamo di un mezzo alternativo sputum artificiale per studiare sensibilità agli antibiotici di Pseudomonas aeruginosa biofilm sia in condizioni aerobiche e microaerofili più rappresentativi del polmone fibrosi cistica.

Uso di un terreno dell&#39;espettorato artificiale per testare l&#39;efficacia degli antibiotici contro<em&gt; Pseudomonas aeruginosa</em&gt; In condizioni più rilevanti al polmone Fibrosi Cistica

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

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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

32.7K Views.  University of Liverpool. Current test diagnostici di sensibilità agli antibiotici si basa sulla crescita planctoniche di isolati in ricchi di nutrienti, le condizioni aerobiche. Qui, ci avvaliamo di un mezzo alternativo sputum artificiale per studiare sensibilità agli antibiotici di Pseudomonas aeruginosa biofilm sia in condizioni aerobiche e microaerofili più rappresentativi del polmone fibrosi cistica.

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 e biofilm Saccharomyces cerevisiae in celle di flusso

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

Ricerca

Immunologia e infezioni

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.

Isolamento del RNA Pseudomonas aeruginosa Colonizzare la Murine tratto gastrointestinale

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.

Long Term cronica<em&gt; Pseudomonas aeruginosa</em&gt; Infezione delle vie aeree nei topi

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 Induced Lung Injury Modello

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.

Una polmonite Modello robusto in immunocompetenti roditori per valutare antibatterico efficacia contro<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 modello di topo transgenizzato IL-8 per il<em&gt; In Vivo</em&gt; Monitoraggio a lungo termine delle risposte infiammatorie

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 metodo per testare l&#39;efficacia della lavata a mano per la rimozione di nuovi patogeni infettivi

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

Overexpression and Purification of Human Cis-prenyltransferase in Escherichia coli

Prenyltransferases (PT) are a group of enzymes that catalyze chain elongation of allylic diphosphate using isopentenyl diphosphate (IPP) via multiple condensation reactions. DHDDS (dehydrodolichyl diphosphate synthase) is a eukaryotic long-chain cis-PT (forming cis double bonds from the condensation reaction) that catalyzes chain elongation of farnesyl diphosphate (FPP, an allylic diphosphate) via multiple condensations with isopentenyl diphosphate (IPP). DHDDS is of biomedical importance, as a non-conservative mutation (K42E) in the enzyme results in retinitis pigmentosa, ultimately leading to blindness. Therefore, the present protocol was developed in order to acquire large quantities of purified DHDDS, suitable for mechanistic studies. Here, the usage of protein fusion, optimized culture conditions and codon-optimization were used to allow the overexpression and purification of functionally active human DHDDS in E. coli. The described protocol is simple, cost-effective and time sparing. The homology of cis-PT among different species suggests that this protocol may be applied for other eukaryotic cis-PT as well, such as those involved in natural rubber synthesis.

Overexpression and Purification of Human Cis-prenyltransferase in Escherichia coli

A simple protocol for overexpression and purification of codon-optimized, human cis-prenyltransferase, under non-denaturing conditions, from Escherichia coli, is described, along with an enzymatic activity assay. This protocol can be generalized for production of other cis- prenyltransferase proteins in quantity and quality suitable for mechanistic studies.

Sovrapressione e purificazione dell&#39;uomo<em&gt; Cis</em&gt; -preniltransferasi in<emEscherichia coli</em

Prenyltransferases (PT) are a group of enzymes that catalyze chain elongation of allylic diphosphate using isopentenyl diphosphate (IPP) via multiple ...

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.

Metodi per rilevare amiloidi seguente infezione di polmonare endoteliali cellule citotossiche da Pseudomonas aeruginosa

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

A Delayed Inoculation Model of Chronic Pseudomonas aeruginosa Wound Infection

Pseudomonas aeruginosa (P. aeruginosa) is a major nosocomial pathogen of increasing relevance to human health and disease, particularly in the setting of chronic wound infections in diabetic and hospitalized patients. There is an urgent need for chronic infection models to aid in the investigation of wound pathogenesis and the development of new therapies against this pathogen. Here, we describe a protocol that uses delayed inoculation 24 hours after full-thickness excisional wounding. The infection of the provisional wound matrix present at this time forestalls either rapid clearance or dissemination of infection and instead establishes chronic infection lasting 7&#8211;10 days without the need for implantation of foreign materials or immune suppression. This protocol mimics a typical temporal course of post-operative infection in humans. The use of a luminescent P. aeruginosa strain (PAO1:lux) allows for quantitative daily assessment of bacterial burden for P. aeruginosa wound infections. This novel model may be a useful tool in the investigation of bacterial pathogenesis and the development of new therapies for chronic P. aeruginosa wound infections.

A Delayed Inoculation Model of Chronic Pseudomonas aeruginosa Wound Infection

We describe a delayed inoculation protocol for generating chronic wound infections in immunocompetent mice.

Un modello di inoculazione ritardata dell'infezione cronica di Pseudomonas aeruginosa Wound

Pseudomonas aeruginosa (P. aeruginosa) is a major nosocomial pathogen of increasing relevance to human health and disease, particularly in the setting of ...