Morris G, Brown M R
Department of Pharmaceutical Sciences, Aston University, Birmingham.
Lancet. 1988 Jun 18;1(8599):1359-61. doi: 10.1016/s0140-6736(88)92179-4.
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.
