Serotype diversity and antimicrobial resistance of Streptococcus pneumoniae

Abstract

The pneumococcus (Streptococcus pneumoniae) is a common bacterial pathogen responsible for various infections, especially in children below 5 years of age. The severity of pneumococcal infections varies from self-limiting mucosal infections, including acute otitis media, sinusitis, and noninvasive pneumonia, to life-threatening invasive disease like bacteremia and meningitis. A high incidence of pneumococcal infections is combined with a constantly growing antibiotic resistance of this pathogen. The growing resistance is thought to be associated with misuse of antibiotics and emerging of resistant clones that may spread throughout the entire population. Pneumococcal polysaccharide conjugate vaccines (PCV) contain an assortment of pneumococcal capsular polysaccharides (from 7 to 13) that produce serotype-specific protective antibodies. Since early 2000's, the introduction of PCV into national immunization programs has been shown to substantially decrease the incidence of invasive pneumococcal disease and pneumococcal carriage associated with vaccine-type pneumococci in many countries. In 2014, PCV vaccination was included in the Russian national calendar of prophylactic vaccination. The present article reviews the current literature on serotype prevalence, antibiotic susceptibility, and PCV effect on the evolution of pneumococcus.