Decrease in Pneumococcal Otitis Media Cultures with Concomitant Increased Antibiotic Susceptibility in the Pneumococcal Conjugate Vaccines Era

Introduction: Streptococcus pneumoniae (Spn) is an important causative of otitis media (OM) in children. The pneumococcal conjugate vaccines (PCVs) were gradually introduced into the Israeli National Immunization Program: PCV7 (2009) and PCV13 (2010). We studied the effect of the different PCVs on the incidence and susceptibility patterns of Spn in cultures from children with OM.

Methods: Charts of hospitalized children

Results: We identified 134 children (76 boys, 57%) from 162 pneumococcal cultures were performed. Overall, there was a downward trend in the annual rate of positive Spn cultures in the 3 examined periods: 11.12, 8.48 and 4.11/1000 hospitalized children/year in the pre-PCV years, transition years, and post-PCV13 years, respectively (p=0.08, p=0.04). Based on the 2007-2009 trend, the observed over the predicted Spn cultures ratio rates were 0.47, 0.32, 0.26, 0.24 and 0.14, for 2010-4, respectively. In parallel, the susceptibility of Spn strains to common tested antibiotics significantly increased from the pre-PCV years to the transition years and the post-PCV13 years: Spn strains were sensitive for penicillin in 37%, 51% and 100%; for erythromycin, 46%, 71% and 82%; for trimethoprim/sulfamethoxazole, 32%, 71% and 97%; and for ceftriaxone, 95%, 96% and 100%, respectively.

Conclusion: The introduction of PCVs significantly decreased the incidence rate of pneumococcal OM, and increased Spn susceptibility to common antibiotics.