Introduction and Proliferation of Multidrug‐ResistantStreptococcus pneumoniaeSerotype 19A Clones That Cause Acute Otitis Media in an Unvaccinated Population

Abstract

BackgroundIntroduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in the United States in 2000 was temporally associated with an increase in the incidence of disease caused by Streptococcus pneumoniae serotype 19A (Sp19A) and with increasing drug resistance within this serotype. A causative role of PCV7 was speculated. We prospectively studied the dynamics of acute otitis media (AOM) caused by Sp19A in southern Israel before the introduction of PCV7 MethodsAOM in children ResultsSp19A caused 438 (9.8%) of 4449 pneumococcal AOM episodes, increasing by 63.1% from 1999–2001 (mean ± SD, 8.4% ± 0.8%) to 2004–2006 (mean ± SD, 13.7% ± 0.9%) among Bedouin children, who were characterized by overcrowding and high antibiotic use. Penicillin, erythromycin, and multidrug resistance increased from ConclusionsThe introduction and proliferation of multidrug-resistant Sp19A occurred before the introduction of PCV7. The increasing proportion of antibiotic-resistant Sp19A suggests that antibiotic use plays an important role in the community