[Antibiotic resistance of pneumococci and H. influenzae isolated from the nasopharyngeal flora of children with acute otitis media between 2006 and 2010]

The choice of antibiotics (ATB) to treat acute otitis media (AOM) has to take into account the level of resistance of bacteria species implicated. The aim of this study was to evaluate in France, ATB resistance of pneumococci and H. influenzae isolated from the nasopharyngeal flora, in children with AOM, vaccinated with 7 valent pneumococcal conjugate vaccine (PCV7).From 2006 to 2010, 66 pediatricians performed nasopharyngeal specimens of children 6 to 24 months with AOM. Demographic characteristics, history, vaccination status and symptoms were reported on a case report form transmitted to ACTIV.Of the 3,501 children included (mean age 13.5 ± 5 months), over 98% were PCV7 vaccinated and 41.1% were cared in day care center. A total of 47.3% of children had received ATB within 3 months before inclusion (cephalosporins, 22.6% and amoxicillin clavulanate, 19.2%). Pneumococcus and H. influenzae carriage was respectively 57.9% and 48.2%. Pneumococcal strains with reduced susceptibility to penicillin represented 46.3% of cases (3.9% highly resistant strains and 42.4% intermediate resistant strains). Factors that increased the risk of carrying these strains were: day care center (OR: 1.5, 95% CI: [1.2, 1.9]) and two courses or more of ATB before inclusion (OR: 2.6 (95% CI: [2.0, 3.4]). For H. influenzae strains the proportion of ßlactamases+ producing strains was 17.1% and those with reduced susceptibility due to penicillin binding protein changes (BLNAR+ strains+) accounted for 7.7% of cases. Three factors increased the risk of carriage BLNAR+ ßlactamase+ producing strains: age equal or greater than 12 months (OR: 3.5, 95% CI: [1.2, 10.3]), cephalosporin use (OR: 2.5, 95% CI: [1.0, 6.1]) and two courses or more of ATB before inclusion (OR: 3.1, 95% CI: [1.2, 8.0]).The data in this study (reduction of ßlactamase producing H. influenzae strains and increase of intermediate penicillin pneumococcal strains) should help to change the choice of antibiotics for AOM in children in France, by reducing the role of oral cephalosporins and secondly, by giving frontline amoxicillin ± clavulanic acid.