SIGNS of ear infection in baby may reflect changing bacterial patterns, with Haemophilus influenzae frequently detected.
A prospective cohort study of young children in Western Pennsylvania found that H. influenzae was the most frequently identified bacterial pathogen in middle ear fluid collected from children with acute otitis media. The findings also revealed a substantial prevalence of antibiotic resistant H. influenzae among nasal isolates.
Investigators enrolled 451 children between 6 and 35 months of age from October 2019 through August 2023. Participants were diagnosed with acute otitis media with tympanocentesis, acute otitis media without tympanocentesis, or an upper respiratory infection without acute otitis media.
Nasal specimens were collected from all children. Middle ear fluid was obtained through tympanocentesis from 57 children and tested for Streptococcus pneumoniae, H. influenzae, and Moraxella catarrhalis.
Haemophilus influenzae Dominates Middle Ear Samples
A single bacterial pathogen was detected in the middle ear fluid of 45 of the 57 children, representing 79% of this group. When pathogens detected alone or in combination were considered, H. influenzae was identified in 56% of samples, compared with 23% for M. catarrhalis and 21% for S. pneumoniae.
Only modest agreement was observed between bacteria detected in middle ear fluid and those found in nasal specimens. This suggests that nasal colonization may not reliably indicate which pathogen is present in the middle ear when signs of ear infection in baby or toddler populations emerge.
The S. pneumoniae serotypes detected in middle ear fluid were 3, 11A, 15B, and 19A.
Antibiotic Resistance Remains Clinically Relevant
Among 319 children with acute otitis media, nasal testing detected S. pneumoniae in 46%, H. influenzae in 43%, and M. catarrhalis in 70%.
Most nasal S. pneumoniae isolates were susceptible to penicillin, with susceptibility reported in 134 of 194 isolates. Frequently observed serotypes included 3, 15B, 15C, 23B/B1, 23A, and 35B.
In contrast, almost 40% of children colonized with H. influenzae carried a β-lactamase producing isolate. The researchers concluded that continued surveillance of acute otitis media pathogens and antibiotic resistance could support therapeutic decision making and future vaccine development.
Reference
Martin JM et al. Assessment of bacterial pathogens in young children with acute otitis media: A prospective cohort study in Western Pennsylvania, 2019–2023. J Pediatric Infect Dis Soc. 2026;doi:10.1093/jpids/piag059.
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