Carried pneumococci in Massachusetts children: the contribution of clonal expansion and serotype switching.

ABSTRACT:

Background

Vaccination against 7 serotypes of Streptococcus pneumoniae has led to the near extinction of vaccine serotypes in both disease and asymptomatic carriage. In carriage, vaccine serotypes have been replaced by nonvaccine serotypes.

Methods

We used multilocus sequence typing to analyze a sample of 294 isolates of S. pneumoniae carried by Massachusetts children (aged, 3 months-7 years) and examine the results for serotype switching and association with antimicrobial resistance.

Results

Eighty-six distinct sequence types (STs) were found, 10 of which exhibited a serotype other than that which would be expected from previous carriage samples. We interpret this as evidence of past or recent serotype switching. Switched variants include ST 320, which is a common an

SUBMITTER: Hanage WP 

PROVIDER: S-EPMC3175614 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature