Expansion of a urethritis-associated Neisseria meningitidis clade in the United States with concurrent acquisition of N. gonorrhoeae alleles

Background Increased reports of Neisseria meningitidis urethritis in multiple U.S. cities during 2015 have been attributed to the emergence of a novel clade of nongroupable N. meningitidis within the ST-11 clonal complex, the “U.S. NmNG urethritis clade”. Genetic recombination with N. gonorrhoeae has been proposed to enable efficient sexual transmission by this clade. To understand the evolutionary origin and diversification of the U.S. NmNG urethritis clade, whole-genome phylogenetic analysis was performed to identify its members among the N. meningitidis strain collection from the Centers for Disease Control and Prevention, including 209 urogenital and rectal N. meningitidis isolates submitted by U.S. public health departments in eleven states starting in 2015.