LAUSR

A2059G mutation in the 23S rRNA gene is the only reported mechanism conferring high-level azithromycin resistance (HL-AZMR) in Neisseria gonorrhoeae. Through U.S. gonococcal antimicrobial resistance surveillance projects, we identified four HL-AZMR gonococcal isolates lacking this mutational genotype. Genetic analysis revealed an A2058G mutation of 23S rRNA alleles in all four isolates. In vitro selected gonococcal strains with homozygous A2058G recapitulated the HL-AZMR phenotype. ABSTRACT A2059G mutation in the 23S rRNA gene is the only reported mechanism conferring high-level azithromycin resistance (HL-AZMR) in Neisseria gonorrhoeae. Through U.S. gonococcal antimicrobial resistance surveillance projects, we identified four HL-AZMR gonococcal isolates lacking this mutational genotype. Genetic analysis revealed an A2058G mutation of 23S rRNA alleles in all four isolates. In vitro selected gonococcal strains with homozygous A2058G recapitulated the HL-AZMR phenotype. Taken together, we postulate that the A2058G mutation confers HL-AZMR in N. gonorrhoeae.