Antimicrobial resistance in Streptococcus pneumoniae: Implications for patients with community-acquired pneumonia

Streptococcus pneumoniae is the leading cause of community-acquired pneumon ia, During the past decade, the prevalence of penicillin resistance in S pn eumoniae has increased dramatically, with resistance rates approaching 45% in some areas of the United States. Streptococcus pneumoniae has also acqui red resistance to other commonly used antimicrobials, including cephalospor ins, macrolides, and trimethoprim-sulfamethoxazole. While vancomycin and th e newer quinolones are currently highly active against most strains of S pn eumoniae, reduced susceptibilities to these agents have been identified in some strains. Prior use of antimicrobial agents is the major risk factor fo r colonization and infection with antibiotic-resistant strains. beta -Lacta m antibiotics remain the treatment of choice for infections caused by susce ptible S pneumoniae. The optimum therapy for penicillin-resistant strains r emains unclear. Appropriate empirical therapy for patients with community-a cquired pneumonia depends in part on the community-specific resistance patt erns of S pneumoniae to various antibiotics. In this article, we provide an overview of the development of S pneumoniae resistance to commonly used an tibiotics and discuss the implications of the development of resistance on treatment decisions.