Epidemiology and antimicrobial susceptibility of non-typeable Haemophilus influenzae in otitis media in Taiwanese children

Background: Concerns about non-typeable Haemophilus influenzae (NTHi) in otitis media (OM) have grown after the introduction of pneumococcal conjugate vaccine (PCV). We aim to better understand the clinical role of NTHi in pediatric OM. Methods: Middle ear fluid samples from children <18 years with OM were obtained from 2010 to 2015. For culture-positive episodes (Streptococcus pneumoniae, H. influenzae, Moraxella catarrhalis, and Streptococcus pyogenes), patients' demographic and clinical information were reviewed and analyzed. Results: A total of 783 episodes were included with 31.8% of isolates as positive. S. pneumoniae was recovered in 69.4%, NTHi in 24.6%, M. catarrhalis in 5.6%, and S. pyogenes in 4.0% of culture-positive episodes. The proportion of pneumococcal OM has declined since 2012 (P for trend <0.005), but NTHi OM rose simultaneously (P for trend = 0.009). Factors associated with increased risk of NTHi infection included less spontaneous otorrhea (OR 0.15, 95% CI 0.06 -0.39, P < 0.001), absence of fever (OR 0.30, 95% CI 0.14-0.66, P = 0.003), concurrent sinusitis (OR 2.91, 95% CI 1.36-6.20, P = 0.006), previous ventilation tube insertion (OR 12.02, 95% CI 3.15-45.92, P < 0.001) and recurrent OM (OR 3.43, 95% CI 1.01-11.71, P = 0.049). The susceptibility of NTHi to amoxicillin/clavulanate was 82.0%. Conclusions: NTHi OM has trended upward in the post-PCV era. Concurrent sinusitis, previous ventilation tube insertion, and recurrent OM were associated with NTHi OM implicated a correlation between NTHi and complex OM. In consideration of NTHi infection, we suggest amoxicillin/clavulanate as the first-line therapy for OM among Taiwanese children. Copyright (C) 2017, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC.