Genetic Analysis of Neisseria meningitidis Sequence Type 7 Serogroup X Originating from Serogroup A.
Neisseria meningitidiscauses meningococcal disease, often resulting in fulminant meningitis, sepsis, and death. Vaccination programs have been developed to prevent infection of this pathogen, but serogroup replacement is a problem. Capsular switching has been an important survival mechanism forN. meningitidis, allowing the organism to evolve in the present vaccine era. However, related mechanisms have not been completely elucidated. Genetic analysis of capsular switching between diverse serogroups would help further our understanding of this pathogen. In this study, we analyzed the genetic characteristics of the sequence type 7 (ST-7) serogroup X strain that was predicted to arise from ST-7 serogroup A at the genomic level. By comparing the genomic structures and sequences, ST-7 serogroup X was closest to ST-7 serogroup A, whereas eight probable recombination regions, including the capsular gene locus, were identified. This indicated that serogroup X originated from serogroup A by recombination leading to capsular switching. The recombination involved approximately 8,540 bp from the end of thectrCgene to the middle of thegalEgene. There were more recombination regions and strain-specific single-nucleotide polymorphisms in serogroup X than in serogroup A genomes. However, no specific gene was found for each serogroup except those in the capsule gene locus.
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
Bingqing
B
Zhu
Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, People's Republic of China.
Pingping
P
Yao
Wenzhou Center for Disease Control and Prevention, Wenzhou, People's Republic of China.
Leyi
L
Zhang
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
Yuan
Y
Gao
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
Li
L
Xu
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China.
Na
N
Xie
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China shaozhujun@icdc.cn.|Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, People's Republic of China.
Zhujun
Z
Shao
D016667:Bacterial Capsules / Q000235:genetics* / Q000276:immunology*; D023281:Genomics; D006801:Humans; D008589:Meningococcal Infections / Q000382:microbiology; D009345:Neisseria meningitidis / Q000235:genetics* / Q000276:immunology*; D010802:Phylogeny; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D065288:Serogroup
N. meningitidis; ST-7; capsule switching; recombination; serogroup A; serogroup X