| Resistance of artificial biofilms of Pseudomonas aeruginosa to imipenem and tobramycin. | |
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MedLine Citation:
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PMID: 10052899 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Viable cells of Pseudomonas aeruginosa were entrapped in alginate gel layers and incubated in a minimal glucose (15 g/L)-yeast extract (2 g/L)-salt medium to form artificial biofilm-like structures. After cultivation for 2 days, the biomass distribution inside the polymer was highly heterogeneous. The cell number reached approximately 1011 cells/g gel in the outer regions of the gel structures whereas the inner areas were less colonized (c. 10(8) cells g/gel). Killing of immobilized organisms by imipenem and tobramycin were compared with free-cell experiments (inoculum c. 10(9) cells/mL). Sessile-like bacteria displayed a higher resistance to the two antibiotics used alone or in combination than did suspended cells. Exposure for 10 h to 20 x MIC imipenem and 15 x MIC tobramycin reduced the number of viable immobilized bacteria to 0.3% and 3%, respectively, of the initial cell population, whereas these antibiotic concentrations were much more efficient (bactericidal) against free-cell cultures (5 log kill in 6 h). A synergic effect of tobramycin and imipenem was detected on bacterial suspensions but not on biofilm-like structures. Effective diffusivity measurements showed that the diffusion of imipenem in the alginate layer was not hindered. A slight but significant enhancement of beta-lactamase induction in immobilized cells as compared with their suspended counterparts was insufficient to explain the high resistance of sessile-like bacteria. |
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Authors:
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L Coquet; G A Junter; T Jouenne |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Journal of antimicrobial chemotherapy Volume: 42 ISSN: 0305-7453 ISO Abbreviation: J. Antimicrob. Chemother. Publication Date: 1998 Dec |
Date Detail:
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Created Date: 1999-08-09 Completed Date: 1999-08-09 Revised Date: 2003-11-14 |
Medline Journal Info:
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Nlm Unique ID: 7513617 Medline TA: J Antimicrob Chemother Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 755-60 Citation Subset: IM; S |
Affiliation:
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Laboratoire des Polymères, Biopolymères, Membranes, UMR 6522 du CNRS, Bois Guillaume, France. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Anti-Bacterial Agents
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pharmacology* Biofilms / drug effects* Cells, Immobilized Drug Resistance, Microbial Imipenem / pharmacology* Microbial Sensitivity Tests Pseudomonas aeruginosa / drug effects*, growth & development Thienamycins / pharmacology* Tobramycin / pharmacology* beta-Lactamases / metabolism |
| Chemical | |
Reg. No./Substance:
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0/Anti-Bacterial Agents; 0/Thienamycins; 32986-56-4/Tobramycin; 74431-23-5/Imipenem; EC 3.5.2.6/beta-Lactamases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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