title: The effect of alginate lyase on the gentamicin resistance of Pseudomonas aeruginosa in mucoid biofilms.
abstract: OBJECTIVE
  Pseudomonas aeruginosa can secrete large amounts of alginate during chronic infections and this has been associated with high resistance to antibiotics. The major aim of this study was to investigate whether degradation of extracellular alginate by alginate lyase would increase the sensitivity of Ps. aeruginosa to gentamicin, an aminoglycoside antibiotic.
  
  
  RESULTS
  Degradation of alginate from Ps. aeruginosa was monitored using a spectrometric assay. Alginate lyase depolymerized alginate, but calcium and zinc cations at concentrations found in the cystic fibrosis lung reduced enzyme activity. Biofilms formed on agar were partially degraded by alginate lyase, but staining with crystal violet showed that the biomass of biofilms grown in liquid was not significantly affected by the enzyme. Viability testing showed that the sensitivity to gentamicin of biofilm bacteria and of bacteria released from biofilms was unaffected by alginate lyase.
  
  
  CONCLUSIONS
  Our results show that at least under the conditions used here alginate lyase does not affect gentamicin resistance of Ps. aeruginosa.
  
  
  CONCLUSIONS
  Our study indicates that alginate does not contribute to resistance to gentamicin and so does not provide support for the concept of treating patients with alginate lyase in order to increase the antibiotic sensitivity of Ps. aeruginosa.
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand.
authors.forename: L A P
authors.initials: LA
authors.lastname: Germoni
authors.affiliation: Department of Food Science, University of Otago, Dunedin, New Zealand.
authors.forename: P J
authors.initials: PJ
authors.lastname: Bremer
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand.
authors.forename: I L
authors.initials: IL
authors.lastname: Lamont
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects*; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D005839:Gentamicins; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase
keywords: Pseudomonas aeruginosa; alginate lyase; antibiotic sensitivity; bacterial alginate; biofilms; cystic fibrosis