Pneumococcus remains main cause of AOM treatment failure in France, even with widespread use of vaccine

Couloigner V. Pediatr Infect Dis J. 2011;doi:10.1097/INF.0b013e3182357c8d.

Among children with acute otitis media treatment failures in France, Streptococcus pneumoniae and nontypeable Haemophilus influenzae were equally distributed, according to results of a study published online.

The researchers also concluded that the main S. pneumoniae serotype was 19A and the main resistance mechanism for nontypeable H. influenzae was beta-lactamase–negative ampicillin resistance.

Before use of a 7-valent pneumococcal conjugate vaccine (PCV7; GlaxoSmithKline) in France, S. pneumoniae and nontypeable H. influenzae were the causative pathogens in AOM treatment failure. Therefore, the researchers set out to describe the epidemiology of pathogens involved in AOM treatment failures or recurrences after implementation of a vaccination strategy.

The multicenter, prospective study enrolled 143 children (mean age 16.9 months) with AOM treatment failure between 2007 and 2009. The researchers reported that 88% of children had received more than one dose of PCV7; 70.6% attended day care.

Failure was defined as the persistence of symptoms after at least 48 hours of antibiotic therapy or their recurrence within 4 days after the end of treatment. History and physical examination findings were recorded, and culture of middle-ear fluid was obtained.

Amoxicillin/clavulanate was the most frequently prescribed antibiotic at the time of treatment failure or recurrence (51.1%). No otopathogens were cultured at the time of treatment failure or recurrence in 35% of cases (n=50).

Similar proportions of S. pneumoniae and nontypeable H. influenzae were observed in the 86 patients (60.1%) from whom only a single species was recovered from middle-ear fluid (46.5% for S. pneumoniae, n=40; and 45.3% for nontypeable H. influenzae, n=39).

Among S. pneumonia strains, 4.4% were penicillin susceptible, 77.8% were penicillin intermediate and 17.8% were fully resistant to penicillin. Serotype 19A represented 84.5% of all serotypes detected.

Among nontypeable H. influenzae isolates, 15.5% (n=7) were beta-lactamase–producing strains; 35.5% of cases were beta-lactamase–negative ampicillin-resistant strains).

Polymerase chain reaction performed in 32 of the 50 sterile middle-ear fluid samples revealed that four were positive for H. influenzae, three for S. pneumonia and three for both.

Disclosure: The study was supported by GlaxoSmithKline. Two of the study researchers are employed by GlaxoSmithKline. The remaining researchers report no relevant financial disclosures.

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