Evolution of Sequence Type 4821 Clonal Complex Meningococcal Strains in China from Prequinolone to Quinolone Era,...

Area of Science:

• Microbiology
• Epidemiology
• Genetics

Background:

• The epidemiology of meningococcal disease in China has shifted from serogroup A (MenA) to serogroup C (MenC).
• This shift is linked to the expansion of the hypervirulent sequence type 4821 clonal complex (CC4821) lineage of Neisseria meningitidis.
• Understanding the evolution and genetic origins of these emergent MenC strains is crucial.

Observation:

• Phylogenetic analysis and traditional genotyping were performed on 76 CC4821 isolates collected in China between 1972-1977 and 2005-2013.
• CC4821 strains of both MenC and MenB serogroups have been detected across China and internationally.
• Evidence of capsular switching between serogroups B and C was observed in epidemic strains.

Findings:

• Recombination events in surface antigen genes and acquisition of quinolone resistance mutations likely contributed to the emergence of CC4821 as an epidemic clone in China.
• The spread of CC4821 strains highlights their adaptability and potential for global dissemination.
• Observed capsular switching raises concerns about the potential for increased MenB disease.

Implications:

• The findings provide insights into the genetic mechanisms driving the emergence and spread of hypervirulent meningococcal clones.
• The international detection of CC4821 strains necessitates enhanced global surveillance.
• The potential for increased MenB disease due to capsular switching is a significant public health concern, particularly given current vaccine limitations in China.