Ability of Antibiotic-Resistant Nonvaccine-Type Pneumococcal Clones to Cause Otitis Media in an Infant Mouse Model of Pneumococcal-Influenza Virus Coinfection.

The introduction of the 7-valent pneumococcal conjugate vaccine in Portugal resulted in reduced carriage in children by vaccine-type strains and an increased carriage of three major antibiotic-resistant clones, ST2191, ST276, and ST63 expressing capsules 6A, 19A, and 15A, respectively. Pneumococcal otitis media (OM), a frequent infection among preschool age children, is often associated with viral coinfection. To evaluate the ability of these three antibiotic-resistant clones to cause disease, we used an infant mouse model of influenza virus pneumococcal coinfection. The 6A and 19A clonal types induced OM, while 15A induced pneumococcal pneumonia and bloodstream infection, suggesting potential for invasive disease.