title: [The assay of beta-lactamase activity in Pseudomonas aeruginosa biofilm].
abstract: OBJECTIVE
  To analyze the resistance mechanism of Pseudomonas aeruginosa biofilm bacteria.
  
  
  METHODS
  An in vitro model of Pseudomonas aeruginosa bacterial biofilm was established in silicon disk with modified flat-board method and a rapid staining procedure of AgNO3 was used to verify it. Biofilm was observed under scanning electron microscopy. The test was carried out in three groups. Group A was planktonic bacteria of Pseudomonas aeruginosa, group B biofilm bacteria of Pseudomonas aeruginosa and group C biofilm bacteria induced by imipenem. The activity of beta-lactamase was quantitated with a spectrophotometric assay method and beta-lactamase quantitation was determined by using Bio-Rad protein assay.
  
  
  RESULTS
  The activity and protein content of beta-lactamase in group B was higher than that in group A by 4.67 and 2.09 times. The activity of group C was 21.86 times as much as that in group A and 4.68 times as much as that in group B. The quantitation in group C was 6.28 times as much as that in group A and 3.00 times as much as that in group B. The activity and quantitation of the three groups were different significantly from each other (P < 0.01).
  
  
  CONCLUSIONS
  The production of beta-lactamase in Pseudomonas aeruginosa biofilm bacteria is one of the main reasons of its resistance.
authors.affiliation: Department of Respiratory, Second Clinical College, China Medical University, Shenyang 110003, China.
authors.forename: X
authors.initials: X
authors.lastname: Gu
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects; D004352:Drug Resistance, Microbial / Q000502:physiology; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology*; D001618:beta-Lactamases / Q000032:analysis* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D015378:Imipenem; D001618:beta-Lactamases