In extraintestinal pathogenic Escherichia coli (ExPEC) strains, mutation in the PstSCAB inorganic phosphate transporter results in multiple sensitivity phenotypes and loss of virulence. Here, we show that a pst mutant is subject to an increased outer membrane permeability and that pst copy number influences fatty acids regulation. Such perturbations are likely to participate in the impaired response of pst mutants to their environment.