Novel modes of action of aminoglycoside antibiotics against Pseudomonas aeruginosa.
Several mucoid strains and one non-mucoid strain of Pseudomonas aeruginosa were grown in subinhibitory concentrations of various aminoglycosides, beta-lactams, and ciprofloxacin. At antibiotic concentrations that did not affect bacterial growth, aminoglycosides inhibited the excretion of alginate capsule and the production of the iron-chelating siderophores. The same concentrations also disturbed other aspects of the bacterium's iron metabolism, manifested by reduced cellular levels of cytochromes and catalase. beta-lactams, except for cefotaxime, and ciprofloxacin did not reduce alginate excretion. These effects on virulence factors are likely to contribute to the efficacy of aminoglycosides.
D000464:Alginates / Q000096:biosynthesis; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D007501:Iron / Q000378:metabolism; D007769:Lactams; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000378:metabolism
D000464:Alginates; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D007769:Lactams; D002939:Ciprofloxacin; D007501:Iron