Etiology and Epidemiology of Children With Acute Otitis Media and Spontaneous Otorrhea in Suzhou, China

Background: There are scare data about bacterial etiology and the antibiotic susceptibility, serotype distribution and molecular characteristics of pneumococci in children with acute otitis media (AOM) in China. Methods: A prospective study was conducted in Suzhou University Affiliated Children's Hospital. All children under 18 years of age diagnosed as AOM and with spontaneous otorrhea were offered enrollment, and collection of middle ear fluid was then cultured for bacterial pathogens. The antibiotic susceptibility, serotypes, macrolide resistance genes and sequence types of Streptococcus pneumoniae strains were identified. Results: From January 2011 to December 2013, a total of 229 cases of AOM with spontaneous otorrhea were identified; of these, 159 (69.4%) middle ear fluid specimens were tested positive for bacterial pathogens. The leading cause was S. pneumoniae (47.2%), followed by Staphylococcus aureus (18.8%) and Haemophilus influenzae (7.4%). The antibiotic resistance rates of S. pneumoniae isolates to erythromycin were 99.1%, and the nonsusceptible rate to penicillin was 54.6%. The most common serotypes identified were 19A (45.1%) and 19F (35.4%). The coverage against PCV7 serotypes for this outcome was 56.1% and of PCV13 was 97.6%. The macrolide resistance was mainly mediated by both ermB and mefA/E genes (88.6%). The CC271 was the major clonal complex identified. Conclusions: S. pneumoniae was a leading cause for AOM in children in Suzhou, China. Antibiotics resistance rates of S. pneumoniae were high and mainly due to the spread of CC271 clonal complex.