Activity of macrolides against uropathogenic Escherichia coli

Abstract

Azithromycin is a macrolide antibiotic extensively used to treat several infections attributa- ble to Gram-positive bacteria. Exceptionally, azithromycin has proven to be effective in clin- ical treatment of widespread chronic infections caused by Gram-negative bacterium, Salmo- nella. While the underlying mechanisms of azithromycin’s activity against this Gram-nega- tive bacterium remain enigmatic, its efficacy brings up the question of whether this macro- lide can be used in treatment of other Gram-negative bacterial infections as well. The goal

of this work was to investigate the possibility of utilizing azithromycin against uropatho- genic Escherichia coli. For this purpose, we determined the minimum inhibitory concentra- tion of azithromycin in conditions resembling intracellular infection sites. Additionally, we

validated the use of four macrolide bioreporters that were based on the regulatory leader peptide coding sequence of the macrolide resistance gene, ermCL.