Background: Before 7-valent pneumococcal conjugate vaccine (PCV7) implementation in France, several studies had described the microbiology of acute otitis media (AOM) treatment failures. The causative pathogens were Streptococcus pneumoniae (Sp) followed by nontypable Haemophilus influenzae (NTHi). The aim of this study was to describe the epidemiology of pathogens involved in AOM treatment failures or recurrences.
Methods: This French multicentric prospective study enrolled 143 children with AOM treatment failure between 2007 and 2009 observed by 8 ear, nose, and throat specialists. Failure was defined as the persistence of AOM symptoms after at least 48 hours of antibiotic therapy or their recurrence within 4 days after the end of treatment. Standardized history and physical examination findings were recorded, and culture of middle ear fluid (MEF) was obtained.
Results: Mean age was 16.9 ± 9.9 months (median, 13.7). Eighty-eight percent of children had received more than 1 dose of PCV7, and 70.6% attended day care. The most common antibiotic used at the time of treatment failure or recurrence was a combination of amoxicillin and clavulanate (51.1%). Bacteriologic sampling demonstrated that in 35% of cases (n=50), no otopathogen was cultured at the time of treatment failure or recurrence. Similar proportions of Sp and NTHi were observed in the 86 patients (60.1%) from whom only a single species was recovered from MEF (46.5% for Sp, n=40 and 45.3% for NTHi, n=39). Among Sp strains, 4.4% were penicillin susceptible, 77.8% were penicillin intermediate, and 17.8% were fully penicillin resistant, and serotype 19A represented 84.5% of all serotypes detected. Among NTHi isolates, 15.5% (n=7) were β-lactamase–producing strains (including 2 strains with only this mechanism of resistance), and strains with reduced susceptibility by changes in protein binding to penicillin (β-lactamase–negative ampicillin resistant strains) represented 35.5% of cases. Among the 50 sterile MEF samples, polymerase chain reaction was performed in 32, of which 4 were positive for HI, 3 for Sp, and 3 for both.
Conclusions: Among children with AOM treatment failures in France, Sp and NTHi were equally distributed; 19A was the main Sp serotype, and the main resistance mechanism for NTHi was β-lactamase–negative ampicillin resistance.
From the *Service d'ORL Pédiatrique, Necker Hospital, AP-HP, Université Paris 5, Paris, France; †ACTIV (Association Clinique et Thérapeutique Infantile du Val de Marne), Paris, France; ‡Service d'ORL, Robert-Debré Hospital (AP-HP), Université Denis-Diderot, Paris 7, France; §Service de Microbiologie, Robert-Debré Hospital (AP-HP), Université Denis-Diderot, Paris 7, France; ¶GlaxoSmithKline Biologicals, Wavre, Belgium; ‖Laboratoire de Microbiologie, Necker Hospital, AP-HP, Université Paris 5, Paris, France; **HEGP (Hôpital Européen Georges Pompidou), Centre National de Référence des Pneumocoques, AP-HP, Université Paris 5, Paris, France; and ††Centre Hospitalier Intercommunal de Créteil, Créteil, France.
Accepted for publication August 31, 2011.
The study was supported by GSK. T.P. and W.P.H. are employed by GlaxoSmithKline, which is a developer and manufacturer of pneumococcal conjugate vaccines. The authors have no other funding or conflicts of interest to disclose.
Address for correspondence: Robert Cohen, MD, ACTIV, 27 rue Inkermann, F94100 Saint Maur des Fossés, France. E-mail: email@example.com or firstname.lastname@example.org.
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