Genomic Epidemiology of Azithromycin-Nonsusceptible Neisseria gonorrhoeae, Argentina, 2005-2019.

Azithromycin-nonsusceptible Neisseria gonorrhoeae strains are an emerging global public health threat. During 2015-2018, the prevalence of azithromycin-nonsusceptible gonococcal infection increased significantly in Argentina. To investigate the genomic epidemiology and resistance mechanisms of these strains, we sequenced 96 nonsusceptible isolates collected in Argentina during 2005-2019. Phylogenomic analysis revealed 2 main clades, which were characterized by a limited geographic distribution, circulating during January 2015-November 2019. These clades included the internationally spreading multilocus sequence types (STs) 1580 and 9363. The ST1580 isolates, which had MICs of 2-4 μg/mL, had mutations in the 23S rRNA. The ST9363 isolates, which had MICs of 2-4 or >256 μg/mL, had mutations in the 23S rRNA, a mosaic mtr locus, or both. Identifying the geographic dissemination and characteristics of these predominant clones will guide public health policies to control the spread of azithromycin-nonsusceptible N. gonorrhoeae in Argentina.