Selective pressure: Rise of the nonencapsulated pneumococcus.

Moreover, nonvaccine serotypes and NESp prevalence have markedly increased since the introduction of pneumococcal vaccines [[5],[6]]. Altogether, the current risk of NESp-associated invasive disease is minimal, with only 1% to 15% of IPD cases associated with NESp depending on the region, but selective pressures and NESp persistence are slowly establishing a suitable environment for a devastating rise in invasive disease [[8]]. Reductions in vaccine serotypes cause propagation of nonvaccine serotypes (pink and purple) and nonencapsulated pneumococci (blue and green). Teal = vaccine serotypes; purple = antibiotic-susceptible nonvaccine serotypes; pink = antibiotic-resistant nonvaccine serotypes; green = antibiotic-susceptible NESp; blue = antibiotic-resistant NESp. [Extracted from the article]