Related Experiment Video
Updated: Aug 6, 2026
Oral Biofilm Sampling for Microbiome Analysis in Healthy Children
Published on: December 31, 2017
Assessment of Bacterial Pathogens in Young Children with Acute Otitis Media: A Prospective Cohort Study in Western
Judith M Martin1, Alejandro Hoberman1, Matthew C Lee1
1School of Medicine, Department of Pediatrics, Division of General Academic Pediatrics, University of Pittsburgh, Pittsburgh, PA 15213, United States.
Insights
Pediatric acute otitis media (AOM) pathogens have shifted post-vaccine. Haemophilus influenzae (Hflu) is now common in middle ear fluid, with antibiotic-resistant strains prevalent in nasal passages, while Streptococcus pneumoniae (Spn) remains largely susceptible.
Area of Science:
- Pediatric infectious diseases
- Microbiology
- Vaccinology
Background:
- Pediatric pneumococcal conjugate vaccines (PCV) introduced in 2000 have reduced Streptococcus pneumoniae (Spn) related acute respiratory illnesses, including acute otitis media (AOM).
- The microbial landscape of AOM has evolved following widespread PCV implementation.
Purpose of the Study:
- To investigate the current bacterial pathogens causing AOM in children.
- To analyze the antimicrobial susceptibility and serotypes of key pathogens like Spn and Haemophilus influenzae (Hflu).
- To compare pathogens found in middle ear fluid (MEF) with those in nasal colonizations.
Main Methods:
- Children aged 6–35 months with AOM or upper respiratory infection (URI) were enrolled.
- Nasal and middle ear fluid (MEF) specimens were collected for bacterial testing.
- Pathogen identification, Spn serotyping, and antimicrobial susceptibility testing for Spn and Hflu were performed.
Main Results:
- Haemophilus influenzae (Hflu) was the most frequent pathogen in MEF (56%), followed by Moraxella catarrhalis (Mcat) (23%) and Spn (21%).
- Nasal colonization revealed Spn in 46%, Hflu in 43%, and Mcat in 70% of children with AOM.
- While most Spn isolates were penicillin-susceptible, nearly 40% of Hflu isolates were beta-lactamase producing, indicating antibiotic resistance.
Conclusions:
- Hflu appears to be an increasingly significant pathogen in pediatric AOM.
- Antibiotic-resistant Hflu strains are common in the nasopharynx of young children.
- Ongoing surveillance is crucial for informing vaccine strategies and clinical treatment decisions for AOM.
Background:
Since the introduction of pediatric pneumococcal conjugate vaccines were introduced in the US in 2000, acute respiratory illnesses, including acute otitis media (AOM) due to Streptococcus pneumoniae (Spn), have declined. Pathogens associated with AOM have changed over time.
Methods:
Children aged 6 through 35 months diagnosed with either AOM (Cohort 1-AOM with tympanocentesis & Cohort 2-AOM without tympanocentesis) or upper respiratory infection (URI) without AOM (Cohort 3) were concurrently enrolled in Pittsburgh, PA. Nasal specimens were collected for all children. Middle ear fluid (MEF) specimens were obtained by tympanocentesis for children in Cohort 1. MEF and nasal specimens were tested for Spn, Haemophilus influenzae (Hflu), and Moraxella catarrhalis (Mcat). Serotypes (Spn) and susceptibility (Spn and Hflu) were determined.
Results:
From October 2019 through August 2023, 451 children were enrolled (Cohort 1: n = 57; Cohort 2: n = 262; Cohort 3: n = 132). For bacterial testing of MEF, 45/57 (79%) had a single pathogen detected. Pathogens detected, alone or in combination in the MEF were Hflu 32/57 (56%), Mcat 13/57 (23%), and Spn 12/57 (21%). Of participants with bacterial pathogens detected in the MEF, there was only modest concordance with the pathogens detected in the nose. Spn serotypes observed in MEF were 3, 11A, 15B, and 19A. Among nasal specimens from children with AOM (n = 319), Spn, Hflu and Mcat were detected in 46%, 43%, and 70%, respectively. The majority (134/194; 69%) of Spn isolates from the nasal specimens were penicillin- susceptible; frequently observed serotypes were 3,15B, 15C, 23B/B1, 23A, and 35B. Almost 40% (63/162) of children colonized with Hflu had a β-lactamase producing isolate.
Conclusions:
Hflu was most frequently identified in MEF, although the sample size was small. In nasal specimens, antibiotic-resistant Hflu were common, while the majority of Spn were penicillin-susceptible. Continued surveillance could provide valuable data to guide vaccine development and therapeutic decision-making.
Related Concept Videos
01:14Atypical Pneumonia
01:30Pneumonia III: Complications and Assessment