The potential impact of the 13-valent conjugate pneumococcal vaccine on antibiotic resistance in pneumococci

Abstract

The emergence of antibiotic-resistant Streptococcus pneumoniae strains is primarily due to a selection of resistant strains by antibiotic use. The majority of antibiotic-resistant pneumococcal strains exist as a limited number of serotypes, many of which are already included in a 7-valent pneumococcal conjugate vaccine (PCV7). Additional non-PCV7 serotypes associated with antibiotic resistance include serotypes that were associated with antibioticresistance prior to the use of PCV7. These include an increase in nasopharyngeal colonisation and disease due to serotype 19A, both following, and in the absence of, PCV immunisation. Although transmission and disease from serotype 19A are likely to decline following immunisation with PCV13, pneumococcal disease associated with antibiotic-resistance due to serotypes not included in 13-valent PCV (PCV13) is likely to persist, albeit at lower rates. The non-PCV13 serotypes already identified to be associated with antibiotic-resistant strains of pneumococci in the pre-PCV13 era will possibly undergo selective expansion, and emerge as the new dominant serotypes associated with antibiotic non-susceptibility in the PCV13 era. Comprehensive control of disease from antibiotic non-susceptible pneumococci is likely to require a pneumococcal vaccine that will be effective in preventing nasopharyngeal colonisation from the vast majority of disease-causing serotypes, coupled with the judicious use of antibiotics.