Genomic characterization of Japanese meningococcal strains isolated over a 17-year period between 2003 and 2020 in Japan

Detection of Novel US Neisseria meningitidis Urethritis Clade Subtypes in Japan

“…The 3 J_NmUC N. meningitidis strains (NIID835, NIID836, and NIID838) were isolated from 3 men with urethritis that developed 4–5 days after contact with commercial sex workers for oral sexual services ( Appendix 1 Table). Although N. meningitidis strains from patients with urethritis in Japan are typically classified as ST11026, which is also isolated from healthy carriers ( 29 ), or ST23, which is also isolated from IMD patients and healthy carriers ( 30 ), we identified all 3 J_NmUC N. meningitidis strains as ST11 ( Appendix 1 Table). To further characterize the 3 J_NmUC N. meningitidis isolates as urethritis clade meningococci, we performed WGS, phylogenetic, and serologic analyses.…”

“…To gain insights into the origin of J_NmUC meningococci, we performed phylogenetic analysis by using WGS to compare 9 ST11 IMD isolates from Japan ( 29 ), 1 STI isolate (NmJP12–1) ( 30 ), and 7 IMD MenC isolates from the United States that were genetically close to US_NmUC ( 32 ) ( Figure 3 ). ST23 J_NmUC-II, ST11 serogroup W meningococci SK001 (NmJP12–1), 8 IMD MenC, and 5 STI MenC ( 30 ) isolates were genetically separate from J_NmUC and US_NmUC meningococci; 7 US IMD MenC that were close to US_NmUC ( 32 ) were also genetically close to J_NmUC.…”

“…US_NmUC, J_NmUC, and J_NmUC-II N. meningitidis isolates have detailed profiles ( Appendix 1 Table). We included 1 sequence type 11 N. meningitidis strain isolated in Japan from a patient with an STI (SK028) and 4 serogroup C meningococci (MenC) that were phylogenetically close to SK028 (PE5, PE6, PE7, and LNP26948) ( 29 ). Moreover, we included 7 MenC phylogenetically close to US_NmUC (IMD strains in the United States) ( 31 ), 2 sequence type 11 MenC isolated from IMD patients during 2003–2020 in Japan (NIID647 and NIID716) ( 28 ), and 6 MenC phylogenetically close to the 2 MenC from Japan ( 28 ).…”

“…US_NmUC appears to have originated during 2006–2012 in the United States ( 32 ), and the ancestral strain might have been imported into Japan during the same period. However, MenC, serogroup W, and CC11 meningococci have rarely been detected in Japan for >40 years, even in IMD patients ( 29 , 47 , 48 ). Although CC11 meningococci have never been identified as a causative agent for meningococcal urethritis in Japan ( 29 ), J_NmUC meningococci, as well as the ST11 ancestral strain, might be dormant in the urethra or pharynx of persons in Japan.…”

“…However, MenC, serogroup W, and CC11 meningococci have rarely been detected in Japan for >40 years, even in IMD patients ( 29 , 47 , 48 ). Although CC11 meningococci have never been identified as a causative agent for meningococcal urethritis in Japan ( 29 ), J_NmUC meningococci, as well as the ST11 ancestral strain, might be dormant in the urethra or pharynx of persons in Japan. Therefore, further analyses of meningococcal isolates from healthy carriers and patients with urethritis will provide insights into dissemination of the N. meningitidis urethritis clade among the human population in Japan.…”