title: Beta-lactam resistant Pseudomonas aeruginosa strains emerging during therapy: synergistic resistance mechanisms.
abstract: The emergence of beta-lactam resistant strains of Pseudomonas aeruginosa during treatment was studied. Three different strains present before treatment persisted with changes in their beta-lactam resistance during treatment. The isolates before and after therapy were studied for beta-lactamase production and permeability barrier. The increased beta-lactam resistance was correlated with an increased permeability barrier. In order to verify if the permeability barrier was correlated with changes in outer membrane proteins, outer membrane preparations were analyzed by SDS-PAGE. Several differences were observed between the OMP profiles of the post therapy and the pre therapy isolates. Furthermore, an analysis of PBPs pattern of strains studied was carried out and alterations in target proteins were observed.
authors.affiliation: Institute of Microbiology, University of Pavia, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Pagani
authors.forename: M
authors.initials: M
authors.lastname: Debiaggi
authors.forename: R
authors.initials: R
authors.lastname: Tenni
authors.forename: P M
authors.initials: PM
authors.lastname: Cereda
authors.forename: P
authors.initials: P
authors.lastname: Landini
authors.forename: E
authors.initials: E
authors.lastname: Romero
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000032:analysis*; D002463:Cell Membrane Permeability; D004352:Drug Resistance, Microbial; D006602:Hexosyltransferases; D006801:Humans; D002267:Muramoylpentapeptide Carboxypeptidase / Q000032:analysis*; D009154:Mutation; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D010957:Plasmids; D018272:Porins; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000032:analysis / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D018272:Porins; D047090:beta-Lactams; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D001618:beta-Lactamases