International Microbiology, Vol 13, No 4 (2010)

Aminoglycoside resistance of Pseudomonas aeruginosa biofilms modulated by extracellular polysaccharide

Wajiha Khan, Steve P. Bernier, Sherry L. Kuchma, John H. Hammond, Fariha Hasan, George A. O’Toole


Pseudomonas aeruginosa is an opportunistic pathogen that produces sessile communities known as biofilms that are highly resistant to antibiotic treatment. Limited information is available on the exact role of various components of the matrix in biofilm-associated antibiotic resistance. Here we show that the presence of extracellular polysaccharide reduced the extent of biofilm-associated antibiotic resistance for one class of antibiotics. Minimal bactericidal concentration (MBC) for planktonic and biofilm cells of P. aeruginosa PA14 was measured using a 96 well microtiter plate assay. The MBC of biofilm-grown ΔpelA mutant, which does not produce the Pel polysaccharide, was 4-fold higher for tobramycin and gentamicin, and unchanged for ΔbifA mutant, which overproduces Pel, when compared to the wild type. Biofilms of pelA mutants in two clinical isolates of P. aeruginosa showed 4- and 8-fold higher MBC for tobramycin as compared to wild type. There was no difference in the biofilm resistance of any of these strains when tested with fluoroquinolones. This work forms a basis for future studies revealing the mechanisms of biofilm-associated antibiotic resistance to aminoglycoside antibiotics by P. aeruginosa [Int Microbiol 2010; 13(4):207-212]

Full Text: PDF

Sello de Calidad FECYT



5-year Impact Factor of International Microbiology is 2,10.

The journal is covered in several leading abstracting and indexing databases, including the following ones: AFSA Marine Biotechnology Abstracts; Biological Abstracts; Biotechnology Research Abstracts; BIOSIS Previews; CAB Abstracts; Chemical Abstracts; Current Contents–Agriculture, Biology & Environmental Sciences; EBSCO; Embase; Food Science and Technology Abstracts; Google Scholar; IEDCYT; IBECS; Latíndex; MedBioWorld; PubMed; SciELO-Spain; Science Citation Index Expanded; Scopus


Creative Commons License

This work, including photographs and other illustrations, unless the contrary is indicated, is subject to an Attributions–Non-Commercial–ShareAlike 3.0 Creative Commons License, the full text of which can be consulted at You are free to share, copy, distribute and transmit the work provided that the author is credited and reuse of the material is restricted to non-commercial purposes only and that if you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one. 


Copyright ® 2013 by Spanish Society for Microbiology (SEM)