Penicillin-Resistant S Pneumoniae

Penicillin-Resistant S Pneumoniae

Although vaccination initially reduced resistance, ensuing strain replacement has curbed that effect

Background

Streptococcus pneumoniae, also known as pneumococcus, is the most common cause of community-acquired pneumonia (CAP) and a common cause of otitis media (middle-ear infections) and bacterial meningitis. The bacterium strikes primarily pediatric populations and, to a lesser extent, elderly patients. Whereas life-threatening conditions were once resolved with penicillin, treatment has become harder and costlier because of the rapid proliferation of drug-resistant strains since the 1970s. 

Pneumococcal diseases are preventable by vaccine: since 2000, the heptavalent protein-conjugate pneumococcal vaccine (PCV-7) has been universally administered to children under the age of 2, under the tradename Prevnar. Although PCV-7 decreased the incidence of disease, particularly in its first years, in the long run the vaccine appears to have caused a shift in strains and a compensatory resurgence in drug resistance. In 2010 the formulation was succeeded by the updated PCV-13 vaccine which covers more but not all resistant strains.