# Characteristics and antimicrobial susceptibility of bacteria causing acute otitis media in children at Vietnam National Children’s Hospital: a cross-sectional study

## TL;DR

This study identifies bacteria causing ear infections in Vietnamese children and finds high antibiotic resistance, which could help improve treatment and prevention strategies.

## Contribution

The study provides up-to-date data on AOM-causing bacteria and their antibiotic resistance in Vietnam, where pneumococcal vaccines are not yet widely used.

## Key findings

- Non-typeable Haemophilus influenzae was the most common cause of acute otitis media in children ≤5 years old in Vietnam.
- High resistance to common antibiotics like amoxicillin and azithromycin was observed in H. influenzae and S. pneumoniae isolates.
- Most children with AOM had a history of previous AOM, and over half were aged ≤2 years.

## Abstract

Acute otitis media (AOM) is a leading cause of healthcare visits, antibiotic prescription and complications in children aged under 5 years. Following the introduction of pneumococcal conjugate vaccines (PCVs), non-typeable Haemophilus influenzae (NTHi) has become the most common causative agent for AOM, followed by Streptococcus pneumoniae and Moraxella catarrhalis. PCVs are not yet included in the National Immunization Program in Vietnam.

To determine the frequency and characteristics of the pathogens related to AOM in Vietnam in children ≤5 years old.

This was a cross-sectional study performed at the Vietnam National Children’s Hospital from October 2021 to December 2023 in children ≤5 years old diagnosed with acute suppurative otitis media. Clinical features of the children were described. Pathogens of interest were identified by culture or real-time PCR (rtPCR). The antibiotic susceptibility profiles of H. influenzae and S. pneumoniae isolates were determined.

In total, 482 children ≤5 years old were included, of which 70.8% were ≤2 years old and 61% had an history of AOM. The most frequent bacteria isolated were H. influenzae (52.1%, 99.6% of which were NTHi) and S. pneumoniae (41.1%). Most S. pneumoniae isolates were resistant to azithromycin, clarithromycin and cefuroxime. Most H. influenzae isolates were resistant to amoxicillin, cefixime, cefuroxime, azithromycin and clarithromycin.

The pathogens most frequently associated with AOM in this study were in line with previous findings. Many isolates were resistant to commonly given oral antibiotics. These results can inform decision-making on AOM prevention and treatment strategies in Vietnam.