Pneumonia Due to Drug-Resistant Streptococcus pneumoniae.

Pneumonia is a major infectious disease associated with significant morbidity and mortality, with Streptococcus pneumoniae the predominant pathogen in community-acquired cases, accounting for 20% to 50% of bacterial cases. Although pneumococcal resistance to β-lactams is now common worldwide, high-dose parental penicillin G, many other parental β-lactams and some oral β-lactams continue to be efficacious. The new Clinical and Laboratory Standards Institute susceptibility breakpoints for parental penicillin G for nonmeningeal infections (≤2 μg/mL, susceptible; 4 μg/mL, intermediate; ≥8 μg/mL, resistant) introduced in 2008 facilitate appropriate reporting and use of penicillin G. Pneumococcal vaccine usage in children from 2000 has led to significant decreases in morbidity and mortality due to S. pneumoniae in all age groups, and the increase in resistant serotypes, such as 19A, appears to be decreasing following the introduction of an expanded valence vaccine in 2010. Judicious use of antimicrobial agents is the best long-term approach in order to reduce S. pneumoniae resistance.