* Capsular Switching
and Other Large-Scale Recombination Events in Invasive Sequence Type 1 Group B Streptococcus
Pneumococcal capsular switching
: a historical perspective.
The case of a new sequence type 7 serogroup X Neisseria meningitidis infection in China: may capsular switching
change serogroup profile?
Mechanisms for changes in serotype prevalence include serotype replacement and capsular switching
(genetic serotype switch in individual organisms) (14).
in group B Streptococcus CC17 hypervirulent clone: a future challenge for polysaccharide vaccine development.
Recombination leading to capsular switching
has been reported numerous times in GBS (3, 6, 8).
So-called capsular switching
might have contributed to increasing non-PCV7 serotype disease (28).
meningitidis core genome amino acid sequences showed that all 22 sequenced CC4821 strains were closely related, irrespective of serogroup, ST, and PorA type, which indicated capsular switching
between serogroups C and B.
However, this association could be disrupted because of capsular switching
caused mainly by recombination of capsular genetic loci.
Recently, recombination of the cps gene encoding capsular polysaccharides among pneumococcal strains with different capsular types, called capsular switching
, was observed by Brueggemann et al.
meningitidis has multiple genetic mechanisms to alter its antigenic profile, including capsular switching
. Capsular switching
has been observed among pneumococcal serotypes after the 7-valent pneumococcal conjugate vaccine was introduced in the United States, although the substantial declines in incidence of pneumococcal disease were maintained overall (25).
Some of these clones, namely, cc11 and cc32, have undergone capsular switching
. For instance, the 2-2:P1.5-1,10-8:F3-6:ST-7816 (a single locus variant of ST-11) clone from 2009 was found to express a serogroup W capsule (10), and the 3-79:P1.7-1,1:F5-1:ST-639 clone was previously demonstrated to belong to serogroup B (3).