title: Intracellular polyamine pools, oligopeptide-binding protein A expression, and resistance to aminoglycosides in Escherichia coli.
abstract: The role of intracellular free polyamine (putrescine and spermidine) pools in multiple resistance to aminoglycoside antibiotics was investigated among in vitro selected kanamycin-resistant Escherichia coli J53 mutants expressing diminished oligopeptide-binding protein (OppA) levels and/or defective ornithine decarboxylase (ODC) activity. The results suggest that diminished OppA content, but not defective ODC activity expression, increased the relative concentration of free spermidine as compared to the wild type strain. Moreover, by adding exogenous polyamines or polyamine synthesis inhibitors to cultures with different mutant strains, a direct relationship between the intracellular OppA levels and resistance to kanamycin was revealed. Collectively these results further suggest a complex relation among OppA expression, aminoglycoside resistance and polyamine metabolism.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, 05508-000 São Paulo, SP, Brazil.
authors.forename: Maria B R
authors.initials: MB
authors.lastname: Acosta
authors.forename: Rita C Café
authors.initials: RC
authors.lastname: Ferreira
authors.forename: Luís C S
authors.initials: LC
authors.lastname: Ferreira
authors.forename: Sérgio Olavo P
authors.initials: SO
authors.lastname: Costa
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D015151:Immunoblotting; D008074:Lipoproteins / Q000235:genetics*; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008074:Lipoproteins; D011073:Polyamines; C046506:oligopeptide-binding protein, bacteria; D009955:Ornithine Decarboxylase; D013095:Spermidine; D011700:Putrescine