Forging new antibiotic combinations

A new paper by PhD student Derek Chan and undergraduate thesis student Irene Guo was published today in Antimicrobial Agents and Chemotherapy: (

Derek and Irene built on previous work from the lab showing that the old gram positive antibiotic thiostrepton had potent activity against Pseudomonas aeruginosa and Acinetobacter baumanii under conditions of low iron, because it is taken up via receptors for the iron-binding siderophore, pyoverdine. A combination of thiostrepton and deferisirox, an iron chelator, had great activity against most, but not all strains, prompting Derek and Irene to search for new molecules that could be combined with thiostrepton to kill those tough strains. They identified several iron-binding antibiotic (indicated by spectral shifts, see picture) and non-antibiotic compounds that when combined with thiostrepton, could wipe out even the toughest of strains. This work was supported by NSERC and Cystic Fibrosis Canada.