Genomic Characterization of Neisseria gonorrhoeae Strains from 2016 U.S. Sentinel Surveillance Displaying Reduced Susceptibility to Azithromycin.

In 2016, the proportion of isolates with reduced susceptibility to azithromycin rose to 3.6%. A phylogenetic analysis of 334 isolates collected in 2016 revealed a single, geographically diverse lineage of isolates with MICs of 2 to 16 μg/ml that carried a mosaic-like locus, whereas the majority of isolates with MICs of ≥16 μg/ml appeared sporadically and carried 23S rRNA mutations.

Evidence of Recent Genomic Evolution in Gonococcal Strains With Decreased Susceptibility to Cephalosporins or Azithromycin in the United States, 2014-2016.

Background: Given the lack of new antimicrobials or a vaccine, understanding the evolutionary dynamics of Neisseria gonorrhoeae is a significant public and global health priority. We investigated the emergence and spread of gonococcal strains with decreased susceptibility to cephalosporins and azithromycin using detailed genomic analyses of gonococcal isolates collected in the United States, 2014-2016.

Methods: We sequenced genomes of 649 isolates collected through the Gonococcal Isolate Surveillance Project.