Differences in sensitivity to PA-1806 among iron transport mutants of Pseudomonas aeruginosa compared to Escherichia coli

Previously, a catechol-containing monobactam called BMS-180680 (now referred to as PA-1806), containing a catechol analog directly linked to the oxime side chain of the monobactam nucleus, was reported to have in vitro activity against gram-negative bacteria, including P. aeruginosa. Characterization of the uptake of the drug into bacterial cells was tested using iron transport mutants of Escherichia coli. It was shown that for the tonB mutants and the cir fiu double mutants the MICs of PA-1806 were the highest. We investigated whether similar P. aeruginosa strain PAO1 iron transport mutants would display the same PA-1806 sensitivity profiles.