Serogroup Y Clonal Complex 23 Meningococcus in China Acquiring Penicillin Resistance from Commensal Neisseria lactamica Species.

Invasive meningococcal disease (IMD) due to serogroup Y Neisseria meningitidis (NmY) is rare in China; recently, an invasive NmY isolate, Nm512, was discovered in Shanghai with decreased susceptibility to penicillin (Pen). Here, we investigated the epidemiology of NmY isolates in Shanghai and explored the potential commensal Neisseria lactamica donor of the Pen NmY isolate. A total of 491 N. meningitidis and 724 commensal spp. isolates were collected. Eleven NmY isolates were discovered from IMD ( = 1) and carriers ( = 10), including two Pen isolates with five-key-mutation-harboring (F504L-A510V-I515V-H541N-I566V) genes. Five of the eight ST-175 complex (CC175) isolates had a genotype [Y:P1.5-1,2-2:F5-8:ST-175(CC175)] identical to that of the predominant invasive clone found in South Africa. Only one invasive NmY CC23 isolate (Nm512) was discovered; this isolate carried a novel Pen allele, which was identified in commensal N. lactamica isolates locally. Recombination analysis and transformation of the allele highlighted that N. meningitidis Nm512 may acquire resistance from its commensal donor; this was supported by the similar distribution of transformation-required DNA uptake sequence variants and the highly cognate receptor ComP between N. meningitidis and N. lactamica. In 2,309 NmY CC23 genomes from the PubMLST database, isolates with key-mutation-harboring genes comprised 12% and have been increasing since the 1990s, accompanied by recruitment of the and/or quinolone resistance allele. Moreover, was predominant among genomes without key mutations in . These results strongly suggest that Nm512 is a descendant of the -harboring CC23 isolate from Europe and acquired its penicillin resistance locally from commensal N. lactamica species by natural transformation.