Mutations in 23S rRNA Confer Resistance against Azithromycin in Pseudomonas aeruginosa

The emergence of antibiotic-resistant Pseudomonas aeruginosa is an important concern in the treatment of long-term airway infections in cystic fibrosis patients. In this study, we report the occurrence of azithromycin resistance among clinical P. aeruginosa DK2 isolates. We demonstrate that resistance is associated with specific mutations (A2058G, A2059G, and C261IT in Escherichia coli numbering) in domain V of 23S rRNA and that introduction of A2058G and C2611T into strain PAO1 results in azithromycin resistance.